350x power gains....

[MassTrike]

What are the best mods to do for a 350x to make it rip? Im looking into getting an exhaust, I used to have a Cobra on my old 350x and it sounded cool. But im not sure how much it improved over stock because i got the bike with it installed already... As for gearing, I do alot of MX style riding and some trails. I took a look at the Powroll 393cc kit, it looks like a nice mod. If I were getting a cobra exhaust, would I bump up my main to a 145 and move the needle to 2 spaces above bottom? I really dont feel like tearing TOO deep into the motor right now, Id settle for a cam to start me off. Let me know what you guys think, I never was big into going inside a 4 stroke motor. Thanks.

[MO350X]

1. Exhaust: I used the 450R muffler. They're a dime a dozen on Ebay, they flow plenty stock-remember they're designed for a 33+ 450R and the 350X is LUCKY to make 27.. ;) Cobra's are just plain obnoxious loud and the paint is junk. The 450R is STAINLESS steel and Honda quality.
2. Remove the air box lid, install UNI filter.
3. Bump up the main to a 142.
4. See how it performs before moving the needle position.
5. Don't change the gearing until you ride it with the above changes....it'll be a WHEELIE machine. :)
These all worked EXCELLENT for me.
I'm at approx. 420 feet above sea level.

Think long and hard about the cam swap.
It'll radically alter your powerband (and possibly reliability) and more than likely you'll need new valve springs.
I look at dollars spent versus performance gained.
Powroll make some awesome stuff but GOOD HEAVENS they're expensive.
Not cost effective by any means.......unless you're independently wealthy then go ahead and enjoy! :p

[350x'inNY]

1. Exhaust: I used the 450R muffler. They're a dime a dozen on Ebay, they flow plenty stock-remember they're designed for a 33+ 450R and the 350X is LUCKY to make 27.. ;) Cobra's are just plain obnoxious loud and the paint is junk. The 450R is STAINLESS steel and Honda quality.
2. Remove the air box lid, install UNI filter.
3. Bump up the main to a 142.
4. See how it performs before moving the needle position.
5. Don't change the gearing until you ride it with the above changes....it'll be a WHEELIE machine. :)
These all worked EXCELLENT for me.
I'm at approx. 420 feet above sea level.

Think long and hard about the cam swap.
It'll radically alter your powerband (and possibly reliability) and more than likely you'll need new valve springs.
I look at dollars spent versus performance gained.
Powroll make some awesome stuff but GOOD HEAVENS they're expensive.
Not cost effective by any means.......unless you're independently wealthy then go ahead and enjoy! :p

Very well said.... my "Go-Go" has a high compression piston, Cobra exhaust (with larger dia. headers) and a UNI filter... ended up taking it to a 142 jet at Trikefest '04 and moved the clip on the needle down one position? (seems like it was down.... not up... could be wrong.... which ever direction it is to richen it up) I think it runs a little rich now..... one of these days soon I'll take it for a check up down to the "nbanned and nameless" hahaha

Bruce

[DeePa]

does the 450r muffler just bolt onto the header and mount right up to the frame without any mods?

Thanks, and great thread...pete, hit me up when you want to go riding, i figure you werent around sunday because you picked that 350x up.

[MO350X]

does the 450r muffler just bolt onto the header and mount right up to the frame without any mods?

It's an easy installation.
It will mount to one of the grab bar bolt locations and you'll have to fab an intermediate tube from the stock headpipe to the 450R inlet.
EASY! Believe me.
You COULD take it to a local muffler shop....someone you KNOW...and they may be able to do the intermediate pipe FOR you CHEAP.
It's only 10-12" of small dia. tubing anyway.
Anyhow, it's well worth the effort considering how much you'll spend versus the cost of an aftermarket pipe.

Here is a link to my original thread on the TRX450R muffler installation:
http://www.3wheelerworldforums.com/showthread.php?t=25052

Best of luck!
Gotta love those 350X's! :beer

[BIGCRIP28]

im running full dg krome power exhaust, k&N filter, 145 main jet, center clip on needle.

a wiseco mid or high comp piston and a medium cam would pep it up a good bit probably. I dont want to open my engine for no reason, but if I ever have to I will definitely go with a 10.25:1 wiseco and a medium grind web cam.
like they said powroll makes 3 (i think) different size big bore kits, many different comp ratio pistons, cams.

[Bronchole]

Didn't Honda offer a big bore 400 kit for these?

[HRC1]

Not trying to step on any toes, but i disagree with some of the above statments. I have 2 350x's. An 85' and an 86". The 86 is stock with a uni filter and a DG excellerator with 13 discs in it. It is verry nice condition, and runs a 140 main, needle in upper 2 positions. MAinly because when a 142 is installed it runs as fat as a pig no matter where the needle is. Verry sluggish.
Both bikes have stock front sprocket as you can't get aftermarket case savers. Both bikes have 37T rear sprockets and wear 20 in honda radials. Stock sprocket had me shifting all the time and never let the motor pull. I ride anywhere from dunes to tight trails to mx tracks. Now for the 85". Thsi bike had a cobra pipe and uni when i got it. Had a 138 jet in it and ran just fine. Now it has a 12:1 wiseco piston, mid range megacycle cam, step under the full race cam, a pulsecharger exhaust, no airbox lid, ported by someone who has 30 yrs experience doing so, new valves,Valve springs, and hardfaced rockers, and a 400ex carb that will have a 145 in it by the time * read this. It runs well with a 142 and the needle all the way up, but i'm trying the 145 asap. It drinks a steady diet of torco 110 leaded. This bike is snappy off the bottom, and revs ok, but still i don't know if i would call it radically changed. It still is a 350x and will never rev or feel like a new trx 450. It is fun and quick for what it is, but still has plenty of grunt like the stocker. A motor like this isnt cheap, now was swapping cams, it was a project and i havent had it together for more than a month. I don't expect it to outlive my 86" but you never know. You might like a mod motor, it's a blast, but you might be happier with just a 10.5:1 piston and a good pipe. I have about $400 just in the cam swap, gaskets not included. It's deff something to think about.

[NOS_350X]

HRC on the 85 JUMP UP THOSE JETS. I just put a 12:1 piston in mine with the 400ex carb and am running a 155 main and its still lean. I was dissapointed in the high compression piston with a 145 main i saw praticaly no gain until i changed the jetting. Now ill be beating 250r's. All ive done is ported it, k&n Bassani header, with a full supertrapp with no discs(not the crappy ones made for the 350x) no airbox, and a 15t, front sproket.


masstriker, Get a good exhaust, k&n or uni, get a high compression piston, make shure the jetting is correct and youll have a completely diffrent bike. Possibly the 400ex carb If you want that acclerator pump. I have 4 350x's and it all depends on what you like, the biggest thing that will make your bike fast or handle better is good rear tires.


Also if you want more horespower dont get the 450r exhaust, theres no way that thing will flow better that any of the other ones for the 350x. (dg, cobra, or any other one you can make work) Its a stock exhaust, theres a reason thats the first thing people change to make there 450's go fast.

[350Xccelerator]

my 350x has a supertrapp pipe, with a UNI filter with a 145 main jet, ive ridden it several times and havent had a problem, and noticed huge power gains when i first put everything on.

[MO350X]

Also if you want more horespower dont get the 450r exhaust, theres no way that thing will flow better that any of the other ones for the 350x. (dg, cobra, or any other one you can make work) Its a stock exhaust, theres a reason thats the first thing people change to make there 450's go fast.

Check the TRX450R Honda HRC kit.
Does it come with a new exhaust? No.
It comes with a TIP for the original muffler.
The original 450R muffler flows VERY well-a stock 450R puts out over 33hp, a 350X was LUCKY to make 27 so the flow is PLENTY, just the facts. With an HRC tip, you can support 40hp.
Any gains by using aftermarket over the 450R will be TINY and you'll end up with a LOUD bike whereas the 450R with HRC tip is 96db or less.
My brother has one so I know that's true and they work.

I'd rather spend the money I saved by using the 450R muffler on a carb. swap, a high-compression piston or-if you choose to do so-put the money toward the cam swap.

But to each his own.

[smokey]

Im running a 450r muffler with no tip it was a big improvement over stock. Also has a uni with no airbox lid and a 142 main jet. It is pretty snappy.

[Pigga]

what i did for exaughst is took stock 400ex headers and put them on and made a custom mid pipe to a FMF muffler, i also have k&n, cam, 12:1 piston, next im going to buy the new 39mm 400ex carb then it will really scream

[Blown 331]

what i did for exaughst is took stock 400ex headers and put them on and made a custom mid pipe to a FMF muffler, i also have k&n, cam, 12:1 piston, next im going to buy the new 39mm 400ex carb then it will really scream

That is very interesting. What did it take for you to get the 400EX header on there? Does it look bigger or better than a stock 350X header? I bet an aftermarket 400EX header would do wonders on a built 350X. I had a White Brothers full system on my 400EX and the aftermarket header was much larger, smoother transitions and it was stainless steel!

[Jason Hall]

I Had A 85 350x With A 12.5:1 Piston DG Aluminum Pipe, Web Mid Range Cam, & Springs. Also Put A 400EX Carb On, But If You Don't Open The Intake Boot & Intake Port Up Your Not Getting The Full Use Of The Bigger Carb. If I Did It Again I Would Go With A 10.5:1 Piston, & Also Open The Exhaust Up Under The Valves. Because Mine Would Get Real Hot. I Have Also Seen People Put 2 Oil Coolers On A 350x. If You Don't Like Kicking Your Ass Off, Then Stick With The 10.5:1. As Far As A Big Bore Kit I Would Worry About Heat, & My Right Leg. I Had To Stand In My Wheelie Bar & Roll The Old Girl Around To Compression Stroke & Jump On The Kick Starter. But Man Did She Run.

[HRC1]

I'm not understanding why the bigger jet is needed. I checked ex riders and alot of guys running 350x motors in 250x chassis are using a 145. A 142 is verry snappy in my bike and still shows color, still grey on the electrode. A 148, the stock 400ex jet, is flooding the bike out. I am 9oo ft above sea level. On another note, anything above 140 in the stock, piped 86' runs sluggish with a wet plug. I don't think it would even run with anything above 142. I'll jet the built one this weekend and post the results, plug color, ride report etc. Also, the pulsecharger i'm using historically uses a smaller main, loeaner jetting than bikew without, as it pulls a vac signal stronger than other pipes. But the 86 is supertrapp like piped, and still cannot use any jet larger than 140 without noticible loses in power. What are you guys running the fuel screw at turn wise?

[OldSchoolin86]

That is very interesting. What did it take for you to get the 400EX header on there? Does it look bigger or better than a stock 350X header? I bet an aftermarket 400EX header would do wonders on a built 350X. I had a White Brothers full system on my 400EX and the aftermarket header was much larger, smoother transitions and it was stainless steel!
An aftermarket header would be almost a waste. The only thing usable on a 400ex header for a 350x is the primaries. You have to cut the mid completely out and reconnect a new one that doesn't dive right into the clutch arm. The mid is a lot longer on the 400ex, hits the motor and is the same diameter as the 350x. Your only gain from doing this (besides something custom) is a little more lenth and a .062" ID increase on your primaries.

[Blown 331]

When you say .062 ID increase are you comparing a stock 350X header to a stock 400EX header? If so I'll probably try it when I get a 350X, stock 400EX headers are a dime a dozen. I have one from my 400 plus I know where I would get a few more. A 1/16 of an inch over 2 primaries sounds worth it to me. Probably takes less than an hour to make.

[OldSchoolin86]

When you say .062 ID increase are you comparing a stock 350X header to a stock 400EX header? If so I'll probably try it when I get a 350X, stock 400EX headers are a dime a dozen. I have one from my 400 plus I know where I would get a few more. A 1/16 of an inch over 2 primaries sounds worth it to me. Probably takes less than an hour to make.
Yes, stock to stock comparison. Shouldn't be too hard of a job but you just have to remember you'll have to reconnect the primaries and make a mid pipe.

[AirManCam]

First off, Jason you only have to capitalize the first word in a sentace, not every one.
As for this, the best available 350x pipe would be a supertrapp, and put a K&N airfilter on with the lid off, and you should have a 145 main jet or so (depending on altitude).

[Jason Hall]

Thanks did not realize I was. My 350x is gone I did have a 230 quad sport with a supertrapp pipe & I don't doubt Its a better pipe, mine ran sweet with the DG.