airmancams 78mph 350X

[MR ATC]

first my apologies to the moderators for reopening this subject but it is purly from a technical aspect and a legitamate subject. i asked a question and he responded now i want to clarify

i quote airmancam...

"I changed my gearing to 12/36. The only reason I said that my 350x could beat T_Mans tecate is he said it would go 72 and I said mine would go 78."

so lets look at this...

stock gearing is 13/40 or 3.08 ratio and tops out at 72mph. with stock 22" tires
your gearing is 12/36 or 3.00 ratio so i would say about 74mph. but you are running 18" tires so your most likley toping out at about 68 with a tailwind. and here is why. lets look at this again

13/40 (stock) is 3.08 = 72 mph
13/39 is 3.00 with stock tires =74 mph
13/38 is 2.92 with stock tires =76 mph
12/36 is 3.00 with stock tires = 74 mph

now if a stock 350X with 13/38 will only do 76mph with stock 22" tires. and you have 18" turf tammers. there is no way your doing 78mph. so drop off about 4mph for each 2" of tire size decrease and you have arox. 66mph. then i gave you 2mph for your mods which in reality provide little if anything to your top speed.

[smokinwrench]

then i gave you 2mph for your mods which in reality provide little if anything to your top speed.

Holy Smokes me and Mr ATC agree on something :shock: . I was trying to explain that the other night and I was called the stupid one. You have to have higher rpm's or higher gearing (sprockets,tires) to have a faster top speed. Like I said the mods will get you to your top speed faster.

I think 3 guys on this forum should feel like real idiots. :D LOL

Josh

[smokinwrench]

Not to be rude AMC but I think the only accurate way to check your speed is with a radar gun. While driving beside the pickup one of you could always trying to catch up with the other one and get a false reading of your true speed.

Josh

Or a GPS unit.

[Wickedfinger]

...well I can see I'll be busy for a while editing this one........Guys please stick to the subject.

[MR ATC]

I'm just saying what the speedometer said in the jeep and the ram. I'm not lieing about the speed. I guess the only reason to prove this shizit to you guys is too take a picture of the speedometer saying 78 and me right next too the truck is that the only way to prove it? :(


i was not trying to imply you were liying. i was just curious as to how you determined 78 mph especially after looking at you trike with 18" tires. but before assuming anything just by looking at the tires i asked the question. then after finding out your gear ratio and combining that with your tires and mods i was able to determine your top speed + or - 1.5 mph.

the "jeep" method is inacurate as auto speedo's are typically + or - 5 mph off, and does it still have stock size tires?

with your gear ratio and smaller tires it is impossible for you to go over 70mph. your gearing is no differant then just switching from a 40 tooth rear to a 39 tooth rear sprocket. that alone will only give you 2mph but you went down 4" in tire size which has a bigger negative effect on speed then one tooth on a rear sprocket has positive effect.

[NOS_350X]

...well I can see I'll be busy for a while editing this one........Guys please stick to the subject.

sorry for putting you through that work. i'm a moderator and shouldnt of done that. but sometimes people get mad

[AirManCam]

I'm just saying what the speedometer said in the jeep and the ram. I'm not lieing about the speed. I guess the only reason to prove this shizit to you guys is too take a picture of the speedometer saying 78 and me right next too the truck is that the only way to prove it? :(


i was not trying to imply you were liying. i was just curious as to how you determined 78 mph especially after looking at you trike with 18" tires. but before assuming anything just by looking at the tires i asked the question. then after finding out your gear ratio and combining that with your tires and mods i was able to determine your top speed + or - 1.5 mph.

the "jeep" method is inacurate as auto speedo's are typically + or - 5 mph off, and does it still have stock size tires?

with your gear ratio and smaller tires it is impossible for you to go over 70mph. your gearing is no differant then just switching from a 40 tooth rear to a 39 tooth rear sprocket. that alone will only give you 2mph but you went down 4" in tire size which has a bigger negative effect on speed then one tooth on a rear sprocket has positive effect.

So what gearing should I go too? Im just telling you what the spedometer said. I know that car spedometers are usually off but thats pretty much the only thing I have to check my speed with. I'm amazed I never bought a gps because im a die-hard hunter. Will any gps tell you how fast you are going? And yes the jeep still has the stock tires. But the dodge doesnt thats why im thinking that it was faster with the dodge.

[MR ATC]

So what gearing should I go too?


well if it's top speed your after get rid of the 12 tooth sprocket going smaller on the front give you more power not speed. i personally carry a 12 tooth in my fanny pack this way if i ever find a killer hillclimb i wanna attempt i switch it right in the field and i know i can pull 3rd up most hills. ( i run a 38 in the rear) put a 13 back on then put on a least 20" tires and you'll be around 74mph if you really want 78mph then go with 22" tires. if your stuck on having 18" tires you'll need to go to a 13/30 gearing to get 76mph. small tires are not good for top speed

[ejc042]

I was wondering if you have the formula to determine max top speed on a 350X, based on gearing and tire size. I am building a 350X and want to get good top speed, without sacrificing too much power.
johnnyrebracin@hotmail.com

[MR ATC]

i had the formunla for a long time but with my doemestic problems i lost a ton of my information and resources. however since i've been seting up 350X's for well over 15yrs i can get pretty close just by experiance.
if you want to gain anything more then a few mph's without sacraficing low end you will need to do some motor mods to increase H.P. this way you can run taller gearing and still have low end.

you may be able to contact sidewindersprockets.com they are the ones i got the original formula from. they don't have it on their website but someone there may be able to get it for you.

[ejc042]

I will be running 22" tires. What kind of mods would I need if I wanted to break 80 mph without losing low end. Or how about 85mph.

[NOS_350X]

I used to run a 15 tooth front sproket and a 38 rear (i might have had the stock 40 on tho) with 22's and i was hittin 85+ but i woudnt open it up on the road, it would start bouncing. rember gearing that high will kill clutch plates!!! first is still low enough to climb things.

[ATC crazy]

I will be running 22" tires. What kind of mods would I need if I wanted to break 80 mph without losing low end. Or how about 85mph.


A good bore job would be the best idea for that. My brother's 350X motor was bored to 372 stroker with new rod, piston, cam, and other engine mods. It was geared down for the woods with 22" tires, but would still reach 70MPH. If you do those mods and run a +1 or +2 C/S sprocket, or -2 or so rear sprocket from stock, you would reach 80+MPH easily. The 372 stroker kit will ensure that you have enough power.

[TimSr]

rember gearing that high will kill clutch plates!!!

Heck yeah, youve got slip your clutch until you hit 25mph! Gearing low serves a lot more function than just having enough power to climb. You can ride trails comfortable without constantly slipping and frying clutches. On two strokes, you can keep the RPMs up at low speeds, and ride all day without fouling a plug. (Its not riding "fast" that keeps them cleaned out)

I guess everybody needs to do their own thing, but Ill never understand why a guy will struggle with slipping a clutch all day, to hit speeds that I cant even conceive for an offroad vehicle. Even with competitive drag racing on standard track lengths, most drivers run out of track before they run out of top speed. I would die to see these off road riding areas in which 70mph doesnt offer a high enough top speed! The big (so called) MX track at Haspin is the first MX track Ive ever even hit 6th gear on with my R, using 11/43 gearing on 18" Turf Tamers. My Z with 11/43 driving 22" All Traks hits high gear on Haspin's drag strip, but never tops out before running out of strip. Do you guys race on a 3 mile drag strip or something? Indy 500? Im just really curious as to where or what type of riding you do in which gearing for speeds beyond 70mph offers any advantages at all, other than to be able to say "it will do 95mph". If it'll do 95, what good is it, if you cant use it?

Top speed has little to do with even normal drag racing, unless your running and endless track, and I think its given far more creedance than it deserves, but Im open, if someone can convince me otherwise.

[MR ATC]

A good bore job would be the best idea for that. My brother's 350X motor was bored to 372 stroker with new rod, piston, cam, and other engine mods. It was geared down for the woods with 22" tires, but would still reach 70MPH. If you do those mods and run a +1 or +2 C/S sprocket, or -2 or so rear sprocket from stock, you would reach 80+MPH easily. The 372 stroker kit will ensure that you have enough power.



a +1 front or 14/40 will give you a 2.85 ratio or = to a 13/37 which is good for 77mph

a + 2 front or 15/40 will give you 2.67 or = to 13/35 which is good for 79 mph

nos_350X with a 15/38 combo you have a 2.57 ratio = to a 13/33 which is good for about 81 so 85+ is streching it. and you will lose a lot of low end

if you want to hit 85 you will need a 2.31 ratio or close to it. to get that ratio you would need either a 12/28, 13/30, 14/32, or a 15/35 set up. to mange this and have low end you will need at least 10 more H.P.

to get 10 H.P. your talking pipe,carb,big piston,cam,porting,

[MR ATC]

TIM SR. "Im just really curious as to where or what type of riding you do in which gearing for speeds beyond 70mph offers any advantages at all"

Tim i can't speak for others but were i ride i have plenty of places to open up my trikes and hit top speed. one of those places are dirt roads were if you ride a 350X you'll quickly learn that it winds out too fast and your begging for more top speed. when your on an open "road" 72 is not that fast. also during the winter there are other options (which i won't get into :twisted: ) were you want a lot of top speed and need little low end.

finally Tim, if you have never had your trike held wide open in top gear and been able to pitch it sideways throwing an incredable wall of roost your missing out on some wild riding. me i love pitching it sidways at 70+

[ejc042]

I was not looking to hit 85 I was just curious what it would take. I think aroung 79 looked good. Thanks for the input.
MR ATC-After looking at your info, I was thinking of a 39 rear sprocket ans swapping between 13 and 15 in the front. What kind of top speed would this give me and what kind of power increase would I need with the 15/39 setup to not sacrifice bottom end.

[MR ATC]

15/39 would give you around 80mph. to pull that off and keep your low end you'll need at least a 360 motor with carb, cam, pipe, and porting would definatly let you get the most out of the other mods.

[NOS_350X]

nos_350X with a 15/380 combo you have a 2.57 ratio = to a 13/33 which is good for about 81 so 85+ is streching it. and you will lose a lot of low end


You sure know the math part. I was told I was going around 85 i was racing a 3000GT and he FLEW past me. he said he was going 110 and he thought i was around 85. then he was just cruzing in front of me for a while. you can gain several miles per hour from drafting :-D

[AirManCam]

So say if I used 14/39 sprokets. How would that be. Would it kill my lowend? And how fast would that be good for? :?

[MR ATC]

14/39 would top you out around 79 with 22" tires and would kill your low end. if you stick with your 18's your looking at around 72 mph and you would still have close to stock low end

[350x'inNY]

You need to find one of them mobile radar display's they put out on the side of the road that shows your speed!! They have one setup on campus right now, but I don't think they'd appreciate you racing your 'X' all out on Campus Drive!

Airman I thought one of your 350x's had a speedo on it?

Bruce

[AirManCam]

Ok say I go with 14/39 with 20" tires. What would that give me? Would I still have my low end?

[MR ATC]

Ok say I go with 14/39 with 20" tires. What would that give me? Would I still have my low end?

between 75/76 mph and you'd still have a decent usable low end.

one thing you need to consider this is figuring on the rest of the machine in 100% operating condition. worn clutch plates, chain & sprockets, bearings, all have a roll in this as well

['86X]

Hey Mr ATC. What engine RPM are you using to make these calculations?? If there is any mods done that will allow the engine to rev higher that will affect the top speed. Plus tire pressure, rider weight etc. can also. I know this will not make a 10 MPH difference from your calculations but all of the above can potentially add up to a few MPH.

[NOS_350X]

modds wont make the rpm's any higher

[200x Basket]

modds wont make the rpm's any higher

sure they will. port the head, bigger cam, bigger carb, bigger exhaust. all of that is to move more air. you move more air by turning the engine to a higher rpm. all of these mods also shift the horse power higher into the rpm range and take torque away from the lower rpm range.

[MR ATC]

well to answer '86X...i am using 7000 rpm's because that is were a stock 350X makes it's peak H.P. you are right there are small factors like you mentioned that will effect the outcome but i am basing it on average conditions. my calculations are aproximate and not exact, but damn close.

200xbasket...mods will not make it rev any higher (a 350X does not have a rev limiter and will rev over 10,500 ) but what they will do is move were it makes it's peak power. and usually big bore kits and strokers reduce your peak rpm's

[200x Basket]

200xbasket...mods will not make it rev any higher (a 350X does not have a rev limiter and will rev over 10,500 ) but what they will do is move were it makes it's peak power. and usually big bore kits and strokers reduce your peak rpm's

i agree that strokers will reduce the rpms due to the rotating mass and the increased vibration. i also agree that mods move the power band. SOME mods do increase the RPM. yes a 350x may run 10500 rpm under no load but not will pulling in 5th gear. the mods will allow you to pull the 10500 rpm's in 5th. also some mods like lighter valve springs, lighter crank, lighter piston, lighter flywheel will increase the top rpm as long as it will hold together. i may not be a 350x expert but i do build high $$$ drag cars and a piston that is a few ounces lighter will make alot of difference.

[MR ATC]

i agree that strokers will reduce the rpms due to the rotating mass and the increased vibration. i also agree that mods move the power band. SOME mods do increase the RPM. yes a 350x may run 10500 rpm under no load but not will pulling in 5th gear. the mods will allow you to pull the 10500 rpm's in 5th. also some mods like lighter valve springs, lighter crank, lighter piston, lighter flywheel will increase the top rpm as long as it will hold together. i may not be a 350x expert but i do build high $$$ drag cars and a piston that is a few ounces lighter will make alot of difference.

well since you admit your not a 350X expert i have no problem telling you you do not know what your talking about

1. YES a 350X will run 10,500 in 5th or 6th while under a load
2. if you modify a 350X and use "lighter" valve springs your motor will not last more then a few hours. but this can't happen because nobody is stupid enough to offer lighter springs for the 350X.
3. ALL aftermarket pistons for the 350X are heavier then stock.

remember were not talking about american V8's but japanese singles

[200x Basket]

i guess we can just throw all the physics out the window because you say that the parts are not made. venolia will make a custom piston (have to buy 10 at $100) to fit ANYTHING and you can specify the weight. manely will make you ANY valve you want. you said mods cant make higher rpms and i say they can. i did not say you could go to dennis kirk and pick up a 1000 rpms. race bikes are made to spin spin spin and that is where the power is. i would also bet probe would build you a nice custom h beam rod that could handle the power. i did mean to say lighter VALVES not springs. that was a mistake on my part. ligher springs would float the valves and make contact with a piston.

on a side note. i dont see why anyone would spend $1000's to modify a 350x when a stock 250r will still smoke it??? you MAY be able to make a 350x keep up but put half that $$$$ into a R and you will be screaming.

[MR ATC]

ok since you insist on pushing the issue i will elaborate with my usuall attitude.

you obviously have NEVER built a 350X motor therefore your showing your ignorance when arguing with some who has more 350X experiance in one month then you have in your lifetime.

yes you can always find someone to build you what you want, but why? there is a reason these parts are not avalible from the aftermarket because they DON't last. do you really think i never tried any of the things your talking about? we are not talking about drag motors that only last seconds.( i need more then a few seconds to give me a thrill) we are talking about real world off road so leave the pavement comparisons were they belong. if you had ever built a 350X you would know that using lighter then stock parts is asking for a motor failure especially if you increase H.P.

a stock 350X makes it's peak H.P. at 8000 rpm's but maxes out at 11,000 rpm's why add more rpm's unless you move its peak power to that limit.

finally i put over 7000 into this 350X and no stock R will touch it in its intended purpose. don't think i know what i'm talking about well i do as i have a 250R and i know its place and it is far from stock

[200x Basket]

WOW :shock: we agree on a point. I DID say some mods would increase your RPM's.. I am glad you could figure that out.

I never said i built 350x's or that i would build them. I do build lots of engines for other items.

so it takes $7000 to keep up with the R. put $3500 in the R and eat some dirt.

he wants to go fast, that is his goal. i dont remember him mentioning building an engine or riding on some long gone MX track.

[200x Basket]

but this is all coming from someone that builds 10 second motors and rides a tecate hmmm i see the simularity neither one of them last for any amount of time


actually my car runs ALOT faster then 10 seconds in the 1/4 mile :D

and i have never actually rode my tecate's, that is why i mentioned the the 250r. i have owned a few of them and i have modded a few of them. they are great trikes for racing.

i started the tecate projects because i was bored with the 250r. i use my trikes as a hobby to pass time, not as my life time passion.

[200x Basket]

i said some mods WOULD increase your RPM's. if you cant dosprove that then you shut your pie hole.

i can change my gearing, it is called the ring and pinion gear, ever heard of it?


i was not responding to airman in my original post, i was just correcting an incorrect post.

get back to the original subject and quit stepping around it.

MODS CAN INCREASE YOUR TOP RPM'S

[MR ATC]

i said some mods WOULD increase your RPM's. if you cant dosprove that then you shut your pie hole.

i can change my gearing, it is called the ring and pinion gear, ever heard of it?


i was not responding to airman in my original post, i was just correcting an incorrect post.

get back to the original subject and quit stepping around it.

MODS CAN INCREASE YOUR TOP RPM'S

SIDESTEPPING is what your entire post have been about. i just replied to your misinformed mind on the 350X subject.

yes mods can increase your top rpm's...BUT NOT ON A 350X. it's been tried and failed. it already revs more then it needs. all you can do is move to power to the rpm range you want.

[200x Basket]

[quote="MR ATC"]

yes mods can increase your top rpm's...quote]

so you agree with me????? i said mods could increase your rpm's i did not say that the 350x could handle it.

all i said to the guy was mods can increase your rpm's and you just agreed to that.

thats all folks. 8)

[MR ATC]

you sure like to try and twist things around don't you if your gonna quote me use the whole quote not just a portion of it to suit your needs. I SAID..."yes mods can increase your top rpm's...BUT NOT ON A 350X" and that is what this WHOLE THREAD IS ABOUT 350X

[short4stuff]

Mr. ATC

This is off topic but those tires you have on the rear of your X I have the same ones. I was wondering where you use those. :?:

[MR ATC]

they are just one of my all around type tires i have. i actually use them very little. mostly just for playing around when i don't want to waste my good tires for horseplay. i normally run turf tammers

[AirManCam]

they are just one of my all around type tires i have. i actually use them very little. mostly just for playing around when i don't want to waste my good tires for horseplay. i normally run turf tammers
I thought your 350X got stolen? Did it? Or did you find it? :?

[MR ATC]

they are just one of my all around type tires i have. i actually use them very little. mostly just for playing around when i don't want to waste my good tires for horseplay. i normally run turf tammers
I thought your 350X got stolen? Did it? Or did you find it? :?

it did and no i did not. i should have said i used them

[ATC crazy]

OK...now I am not an engine builder or anything like that either. BUT, I do know that if you throw in a lighter piston, rod, valves, etc...THE 350X WILL TURN MORE RPM'S. If there is no rev limiter, and it will turn 10,500 stock....then if you throw lighter accessories in there it will rev higher. No, I'm not talking about 5K RPM's more, but around 500 or so.

Pick up a cinder block and throw it....now pick up a brick and throw it. Now, which one went farther? :? (the lighter one right)

[MR ATC]

i don't disagree with this, but those parts are not avalible for a 350X because they won't work without destruction. yes you can have them made by someone but if you want i'll make you a wood piston with 15:1 compression. does that mean it will work?

REMEMBER WE ARE TALKING ABOUT A 350X MOTOR. NO ONE MAKES LIGHTER PARTS TO SELL OR USE FOR A REASON

[ATC crazy]

....but It CAN easily be done...

[MR ATC]

....but It CAN easily be done...

no it can't EASILY be done. thats the point. it would take expensive custom machine work just to explode. there comes a point when to much is enough. 11,000 is that point on a 350X. even if you can get the parts to last for short drag racing it still won't rev higher only quicker.

i've tried lightened flywheels and short skirt pistons and all it does is rev QUICKER NOT HIGHER.

[ATC crazy]

How do you know that it didn't rev higher....did you hook up a digital tach or something? And it would be easy for me (just send it to the shop and tell them what you want done to it ;) )

[MR ATC]

How do you know that it didn't rev higher....did you hook up a digital tach or something? And it would be easy for me (just send it to the shop and tell them what you want done to it ;) )

no it was on a dyno

find one that will do it see what they say

[Billy Golightly]

After reading the thread, just a reminder...Keep it civil or keep it elsewhere.

[ATC crazy]

Like 200X Basket said MR ATC


venolia will make a custom piston (have to buy 10 at $100) to fit ANYTHING and you can specify the weight. manely will make you ANY valve you want.

Just give 'em the specs probably. Easy. And I bet anything that it would pull more RPM's

[MR ATC]

you just don't get it do you...it has been tried before and not just by me call powroll, four stroke tech, curtis spraks, xr's only. you will not get past the 11,000 plus rpm a stock 350X will run, just quicker and the peak h.p. rpm range will change. thats it.

[Billy Golightly]

Errmm...well against my better judgement...

The Motor COULD be made to spin faster, it not economical, cheap, or even something you would benefit from. The only Sure-fire way I see of increasing RPM is to decrease the stroke considerbly...like 10-15mm. And then you've killed your compression, and you've got a huge oversquare engine and you run into problems similar like the early XR500's had. You can make the motor spin faster, but your not going to make the motor any better by making it faster. Infact, your going to hurt it. RPM's=Death to an engine. There is a reason engines that turn over 15,000 any kind of considerable amount (More then a day) do not last long.

[AirManCam]

I think this subject is getting out of hand. I mean you knever know every thing is made differently. I have ran alot of stock 350x's and when mine was stock my 350X still beat them so idk. But all i'm tryin to say is Mr ATC. things are made differently

[MR ATC]

Errmm...well against my better judgement...

The Motor COULD be made to spin faster, it not economical, cheap, or even something you would benefit from. The only Sure-fire way I see of increasing RPM is to decrease the stroke considerbly...like 10-15mm. And then you've killed your compression, and you've got a huge oversquare engine and you run into problems similar like the early XR500's had. You can make the motor spin faster, but your not going to make the motor any better by making it faster. Infact, your going to hurt it. RPM's=Death to an engine. There is a reason engines that turn over 15,000 any kind of considerable amount (More then a day) do not last long.

you make a valid point except one thing... it would no longer be a 350 but aprox. a 270? and i agree that smaller displacement motors will rev higher, but we are talking about a 350 and the larger you go the less rpm's you achieve. just like when you increase the stroke on a 350x it lowers the rpm's.

airman things are made differantly but were are talking about a 350X and there is no major differance to dispute. you will not increase the revs on a 350X

[Lots_Of_Nothing]

hahaahah, sorry to cut in guys.....but damn..we got some determined guys on the board.....im jsut wondering how many more pages this is gonna go on for.....haha, i dont mind, i read it every day and lmao, .

........some ppl just gotta admit it when there wrong......
*cough*mratc*cough*

[Billy Golightly]

you make a valid point except one thing... it would no longer be a 350 but aprox. a 270? and i agree that smaller displacement motors will rev higher, but we are talking about a 350 and the larger you go the less rpm's you achieve. just like when you increase the stroke on a 350x it lowers the rpm's.

Right. I'm not denying the fact that you've changed the displacement at all. I'm just talking about the motor. A 250R motor with a sleeve down 200 kit is a still a 250R motor right, with a sleeve down kit, right? And I can even figure it if you bored it back out enough to equalize the same displacement it orginally had, and you raised the compression back to where it was originally. I'm not saying at all you'll gain more power, but I think you will gain some more RPM's-not 3-4K, but you'll gain some. Thats why I said its not economical, cheap, or even worthwhile doing. Because when you decrease the stroke, your talking custom crank/rod/piston. And then if your going to increase the displacement (By bore only) 80cc's Your talking a major big bore kit, and then you've got to remove God only knows how much from the top of the cylinder and the bottom of the head to even the compression back out (I'm figuring you don't dome the piston). And if you were REALLY gonna try and do it you would probably want different bearings, valves, rockers, timing chain, cam, springs, ect as well.

[MR ATC]

..."? And I can even figure it if you bored it back out enough to equalize the same displacement it orginally had, "...

however you would now have a much larger piston being pushed by a smaller rod, not exactly a way to GAIN rpm's

then you have the new 450 4 strokes like the YZF and CRF that use "huge oversquare" arangements and they don't rev past 11,000 if memory serves me correctly. and those motors are built to almost there limit from the factory.

[MR ATC]

hahaahah, sorry to cut in guys.....but damn..we got some determined guys on the board.....im jsut wondering how many more pages this is gonna go on for.....haha, i dont mind, i read it every day and lmao, .

........some ppl just gotta admit it when there wrong......
*cough*mratc*cough*

why should i when i'm not! not one of these guys has built a High Performance 350X motor. :rolleyes: :rolleyes: :rolleyes:

i asked before i'll ask again show me one builder that has achieved more rpms then a stock 350X goes to. not quicker but higher.

[Billy Golightly]

however you would now have a much larger piston being pushed by a smaller rod, not exactly a way to GAIN rpm's

then you have the new 450 4 strokes like the YZF and CRF that use "huge oversquare" arangements and they don't rev past 11,000 if memory serves me correctly. and those motors are built to almost there limit from the factory.


This is where the lighter piston, rod, and crank come in at. Again, I said there wouldn't be a substantial upgrade in RPM's, but there would one, however it will be minute and very slight.

No one builds 350X motors to turn faster because of the reasons I said in a previous post. If time and money were no object you could do it. But after you did one you wouldn't want to do another.

[trikerider2oo7]

my friends has a 350X engine in a 250X frame and itll run about 90

[MR ATC]

This is where the lighter piston, rod, and crank come in at. Again, I said there wouldn't be a substantial upgrade in RPM's, but there would one, however it will be minute and very slight.

Billy it's been tried all it does is rev quicker but not higher.

no 350X motor as a 350 will go over the stock rpm's

i use the 10,500 as a guide only because thats were my tach topped out at and i know how some people can be, they need to see it to belive, so i use that as a referance most of the time. but in reality it will rev to almost 11,500 and this is why i say over 11,000. no matter what you do to a 350X motor and keep it a 350 it will not go over that limit.
you can go bigger but you'll lose RPM's you can go smaller to gain RPM's but its not a 350. making a smaller motor rev higher is no problem.

[smokinwrench]

Well, than lets decrease the stroke and increase the bore and make it a 350 that way.

Then you could have the best of both worlds tighter rapping(12,000 plus from the shorter stroke) and then you could still have the size that will give it the hp.

Josh

[MR ATC]

Billy already mentiond that. but now you will have a smaller rod moving a bigger piston. not gonna rev higher

[Billy Golightly]

I concede Bill. I can't prove I can make a same as stock displacement 350X motor turn faster then 11.5k. BUT, "In Theory" I do believe its possible, hehe.

[MR ATC]

"in theroy" quads are better then trikes :rolleyes: :twisted: :D

[MR ATC]

ok guys in chat tonight Kilborg finally came up with the answer...TURBO...that is the only way you will get a 350X to rev over 11,000+ rpms. i was waiting to see if anyone would come up with it. some good theroy's though.

[NOS_350X]

hahaahah, sorry to cut in guys.....but damn..we got some determined guys on the board.....im jsut wondering how many more pages this is gonna go on for.....haha, i dont mind, i read it every day and lmao, .

........some ppl just gotta admit it when there wrong......
*cough*mratc*cough*

i think this argument is probably the best one ive seen on here. they stayed on topic completly (not the amc's 350 but the rpm's) and its completly clean. and both sides have solid points backing there theorys

[MR ATC]

except one thing mines not theroy but actuall experiance, test, and results.

[NOS_350X]

except one thing mines not theroy but actuall experiance, test, and results.

i knew i should have kept quiet. this is going to start it up again

[KASEY]

Billy already mentiond that. but now you will have a smaller rod moving a bigger piston. not gonna rev higher


this is not true,,,,, you will have a SHORTER rod ,,,, not a smaller rod and there is no reason that it won't be as strong or stronger,,,,,, the 350 engine is a trailprotrailprotrailprotrailprotrailprotrailprotrailpro anyway,,, there are no classes for it to race in,, thats why not very hop up parts,,, or much intrest in building them,,,,, you can believe there will be plenty new yammy and honda 450 quads that will breach the 12,000 rpm barrier without any problems,,,,, and if you don't believe that wake up its 2003!!!!!

[SpeedBump]

Can't you just get some RPMs outta simple "breathing" mods? Last time I checked it worked well poppin on a free flowing air fliter, losing the airbox lid and larger headpipe with a less restrictive silencer. Get small amount of rpms and isn;t that what he is after? Seems in all the dyno tests I have seen, the simple mods I have described gives an engine a small increase in MAXIMUM HP, but a much broader powerband with a higher maximum RPM. OKAY, now Bill can tell me why I am wrong....he will....trust me. :rolleyes:

[TimSr]

At the risk of appearing to live in the real world on planet earth, lets see if if Ive got this right. A guy runs his 350X all the way wound out, and screaming down a stretch of highway in high gear, and wishes to raise his top speed, and some of you guys think engine modifications to turn more RPMs is a practical way to do that?

Most stock motors of any type (without rev limiter) are perfectly capable of turning enough RPMs to quickly turn a motor into shrapnel if you try to maintain high RPMs. It doenst matter what mods you do. If you raise the RPMs of a motor in order to achieve a higher cruising speed, yes, in theory it will achieve a higher speed for a few seconds, but all you will really accomplish is reduce the number of seconds it takes for the screaming motor to grenade. Since you cant maintain extremely high RPMs for more than a couple seconds, engine modifications to increase RPMs are totally irrelevant in any discussion of raising top speed other than how long it takes you to reach it. If I understand the gist of this post, and MrATCs answer to my "why would you want to" question, guys are trying to figure out what top speed to gear for, so they can road cruise at a lower speed in midrange high gear specifically so they dont launch it.

As much is it pains to to publically agree with MrATC, Ive really gotten tired of seeing the extent of silliness this post has reached! Please let it die!!!!!!

[MR ATC]

Kasey, your correct i misspoke i should have said "shorter" however on a 350X motor that will not effectivly increase rpm's. the 450 comparison is irelevent becuase we are not talking about them. i admit other motors can increase there rpm's. aditionally you are misinformed about the amount of hop ups avalible for the 350X motor. it is one of the most versital motors in an ATV and countless combinations are avalible to modify them. the aftermarket is still to this day heavilly involved in them as there are more parts avalible then any other 3wheeler except the 250R.

speed if i answer will you promise not to "punch" me out :rolleyes: :rolleyes: :rolleyes: the breathing mods will increase H.P. but not revs. they will let you rev quicker but not higher.

Tim Sr. unlike you, i have no problem agreeing (sp) with you. and this is the point i've been trying to make. a 350X already revs to high stock, and will grenade itself (i have the broken rods, cases, pistons, cylinders, to prove it.) if the 11,000+ rpm's are maintaned.

[AirManCam]

Mr.ATC what do you mean no one in here has ever built a custom 350x motor. I have! I had built it then it wasnt fast enough. So I took a Xr 500 motor and put it in the 350x chassis. And let me tell you what that would fly!
But I am going to have to agree with TimSr. I think this post is getting a little long and stupid dont you guys think?

[MR ATC]

sorry airman i was not refuring to you just the "350Xperts" arguing with me about RPM's.

for the record what mods did you do? did it increase your RPM's

[Billy Golightly]

[quote="airmancam"]So I took a Xr 500 motor and put it in the 350x chassis. And let me tell you what that would fly!
[quote]

When did you do this? Why am I just now hearing about it? How did you do it and what mods did it involve? How long did it take you to do it? What year XR500 did you use?

[ATC crazy]

MR ATC (or anyone else)...the only way I will believe that a 350X will somehow, "magically" NEVER rev any higher than 11,500RPM's is if:

You get a DIGITAL Tach...not mechanical,,,and rev a stock 350X as high as it will go.

Do all the mods mentioned (lighter piston, rod, etc...) And lighter dosent mean weaker...

Then rev the "new" X up as high as it will go...

I would bet anything that it will rev higher (not 1,000's higher....but higher than 11,500). I know that an engine running like that will "gernade" at some point in time and will be no where near as reliable as stock. But Im saying that it could be done to prove a point.

[MR ATC]

so your saying a dyno is not as acurate as a digital tach???

[ATC crazy]

Did you get readings while it was stock and more readings after lighter piston, rod, etc... :rolleyes:

[MR ATC]

yes at the time we did. i told you before i'm not pulling this out of my arse but by actuall experiance. you should know by now i don't guess these things. do i still have the results from a years ago? no i do not. i tired, i learned, i accepted.

[MR ATC]

no your replies are B.S.

a dyno will tell you severall things such as

peak H.P.
the H.P. throughout the rpm range
peak rpm's
and torque.

to determine your h.p. throughout the rpm range you have to push the motor to its rpm limit.

again i ask you...how many 350X motors have you built?

as for evidence obviously you turn a blind eye when i show it or someone else does for me.

[AirManCam]

I told you guys about it before. I just recently sold it :( It was my modded out 350x that I told you guys about lol. We took an 85 XR500 motor I bought it and then I took the rolling chassis down to my friend Ray that has a little atv shop. I told him to make the motor fit and he did. He rebuilt the motor and changed the frame and motor mounts around and it bolted right up. It took him about three weeks to finish every thing. I still wish I never sold it :evil:

[Wickedfinger]

200X Basket - You are being warned - stop the personal attacks and insults aimed at Mr ATC. Lord knows he dosent need me to defend him, and he can give it as much if not more than he gets it, but he NEVER tries to be hurtful with his comments to anyone like you have to him by bringing up his personal problems. I have removed the offending posts.

[dividebyzero]

I know you guys are more into the (what a motor can do) than me,but going by the manual i know the 350x doesn't have a rev limiter(found that out),but the manual says 7000 rpm's.You mean to tell me that you can build a 350x motor to rev(let's just say more than 10,000 rpm?).Just wondering,not starting an argument here.I found out it's in the gearing that will or not blow a 350x motor since it doesn't have a rev limiter.Example:stock 350x,lower tires by 2 inches(rear),it's going to make the motor spin faster than stock,meaning the motor will over rev,causing damage to the motor,or drop 1 tooth in the front?correct?If this is false let me know.Thanks.

[MR ATC]

452X, the manual says at 7000 rpm's it makes it's peak H.P. it will rev to over 11,000

changing the gearing or tires will not increase peak RPM's only how fast it gets to them or how well it will pull them.

i run anything from 18" - 25" tires and 12/13 front and 40 - 36 rear sprockets. does it effect the rpm's yes but it won't increase them as per reving past 11,000 plus

[TimSr]

Tim Sr. unlike you, i have no problem agreeing (sp) with you. and this is the point i've been trying to make. a 350X already revs to high stock, and will grenade itself (i have the broken rods, cases, pistons, cylinders, to prove it.) if the 11,000+ rpm's are maintaned.

Hey MrATC, just ribbing you a little bit! Trying to lighten up a thread thats turned into total nonsense. I agree with you completely on this one.

To anyone who thinks cruising a 350X at 11,000 RPMs is a good thing, I issue this challenge: Let someone else cruise by you with YOUR 350X screaming at 11,000 RPMs, and Ill wager that you cant stand there silently without yelling out "SHIFT, YOU IDIOT!".

Raising RPMs above peak to "go faster" is the same as holding the throttle wide open without shifting. Gearing up does the same thing as shifting. I really get annoyed with arguments over "techinicalities" when the original post concerns simple practical, and logical information on gearing and top speed, and I think that advising a guy to rebuild his engine to high performance specifications to increase his dirt road cruising speed is really poor advice.

[Ace Mon]

You sure are the goemetry ninjas . I'll tell ya this , I have a 250r 300cc kit with a 42 mm carb and a paul turner full race pipe . (Cant remember the sprockets I have now) . The shop that built it said I would be able to do 90 mph . I doubt it . But even if I could , who really wants to do 90 in the dirt . And by the way pacing yourself with a car that does not have the stock gears or size tires is a waste of time . Lets face it , these things haul ass or we wouldnt have them . For the die hards . Take them to the dragstrip . The time in the 1/4 mile isnt important but they have the best MPH radar at the finish line .

[200x Basket]

mathmatical proof

horsepower = rpm x torque / 5252

torque = 5252 x horsepower / rpm

formulas are from Engine Math by HP books



now disprove that. give me some "real" formulas that says HP will not increase rpms

[200x Basket]

200X Basket - You are being warned - stop the personal attacks and insults aimed at Mr ATC. Lord knows he dosent need me to defend him, and he can give it as much if not more than he gets it, but he NEVER tries to be hurtful with his comments to anyone like you have to him by bringing up his personal problems. I have removed the offending posts.


well you should consider removing all of the B.S. and lying that cant be backed up by one shred of proof. i just give his usual excuse before he got to it. the fact is he is wrong and too stuborn to admit it. i am tired of see this misconception taken as the truth on this board.

[AirManCam]

Wow. This is one post that got way out of hand and way away from the original topic eh? Just quit the arguing! This post takes up way too much space. And its all B.S. Well I dont really have a say but I'm pretty sure I just said what all of you are thinking :?

[Wickedfinger]

... I have no problem with anything else ... just the personal attacks ... this isnt 8th grade homeroom here ... pretty soon this'll degrade into "Your Mom ...." if you guys don't keep it civil. Comments like that along with cursing come out when people get despirate and feel like they are loosing an argument. You called Bull Sh it on him, he came back at you ......

Tim Sr. "SHIFT YOU IDIOT" ... lof'nl!!!

[MR ATC]

-edited-

basket i'm not arguing formula's

listen too me VERY CLOSLY

a 350X makes it's PEAK H.P. at around 7000 rpm's

a 350X will rev over 11,000 rpm's

that leaves you with 4000+ rpm's of OVERREV or wasted RPM's

when you modify the motor you change the powerband and were it makes it's peak H.P.

using lighter parts will alow it to rev quicker but not higher

now here is a misconception you seem not to relize...a 350X motor is not a drag car stop thinking it is. you rev a 350X over 11,000 and it will explode. i don't need to prove it too you i have the blown up motors to prove it to me. DO YOU???

finally since you can't admit you have no experiance building 350X motors and you don't believe me call around.

i challange you to find a 350X builder that can increses the revs over 11,000 +

[200x Basket]

-edited-

and i am not angry at all, i am just tired of a "know it all" crapping out bad information.

my challenge was not wether or not a 350x could rev above 11,000, rpm's.

i challenge you to re-read my post and discover that my statement was that mods could increase your rpm's.

after you figure that out, i challenge you to prove me wrong. you are just to old and stubborn to get to the real point.

[short4stuff]

I told you guys about it before. I just recently sold it :( It was my modded out 350x that I told you guys about lol. We took an 85 XR500 motor I bought it and then I took the rolling chassis down to my friend Ray that has a little atv shop. I told him to make the motor fit and he did. He rebuilt the motor and changed the frame and motor mounts around and it bolted right up. It took him about three weeks to finish every thing. I still wish I never sold it :evil:

Nobody see this one?????????? This says it all..... his 78mph 350x was really a 500x .................................................. ..................

[AirManCam]

No not that 350x. I had 3 350xs. Im talking about a mod one i had built. Not the one that this topic is about. lol. ;)

[MR ATC]

-edited-

and i am not angry at all, i am just tired of a "know it all" crapping out bad information.

my challenge was not wether or not a 350x could rev above 11,000, rpm's.

i challenge you to re-read my post and discover that my statement was that mods could increase your rpm's.

after you figure that out, i challenge you to prove me wrong. you are just to old and stubborn to get to the real point.


I am a know it all when it comes to 350X's, and that is what THIS THREAD is about.

I NEVER said anything about other motors. THIS THREAD is about 350X's, not other motors.

I challenge YOU to RE-READ my post, and you will find out that THIS THREAD is about 350X's.

after you figure out that THIS THREAD is about 350X's, I challenge YOU to PROVE i am WRONG

[Howdy]

Enough is enough. This thread is now locked. Take it private or keep it to yourself.
Howdy