Jetting is no easy task......

[Dirtcrasher]

I can't say I've spent dozens of hours on my 86 200X, but I've spent long enough to say that it's a PITA to get correct....

I jetted my 250r (years ago) and a Blaster with an FMF pipe and that was a piece of cake. Up the main a couple sizes, raise the needle and I was good to go :D

But now, I'm trying to jet a 4 stroke with porting, race cam, race gas, ST exhaust, lightened flywheel etc etc etc.... And it's NOT easy! I've got a white bros 28MM Mikuni on there and it seems to just love fuel! I'm at the point that it runs very well on top but with an air box lid on there. I want that lid OFF and I'm sure I can up that main quite a bit when I take that lid off... Thank god I have about 200$ worth of jets to dick with, and truth be told - thats about what it takes!!

I also must be fat on the pilot and starter circuit because it starts with the choke but bogs down, I can almost immediately take that choke off and it will run. You should always be able to run it on the choke until warm up or it's too rich......

Anyone who says "record all your jetting changes" is SO correct and I also agree on one change at a time, although were always in a hurry to "multitask"

Just sharing my thoughts guys :beer:

So much to do, so much to learn and very little time!!

[SWIGIN]

i HATE those little mikunis (well all mukunis realy) but it can take time.

i happen to like keihin carbs and know within a neddle or 2 and a few jets what will get me close.

over time it gets to be old hat when you build and use the same basic parts.

[Yamahondaman]

Like the Female Jender ..... 4-Stroke's .......... i like em ... "FAT" !! the 400ex we had came stock with the 145 Main .. i had the 178 in it .. it LIKED IT !! the Common Jet for the "DR650" Suzuki is a 150-155 Main (Modded) .. mine has the 170 .. IT LOVES IT !! GO PHAT with the 4-Banger's .. :beer

[honda250sx]

You heard the man GO FAT Steve...

I know a guy that can get better deals on jets... lol

[oscarmayer]

the think your goign to run into is the more you setup for top end on a carb, the worse it runs ont he bottom. there is a balance to be had.
your going to have to jack with the needle jet for the low end and even needle sizes and maybe seats.
it maybe easier to start in the middle and work your way up on the main. i always follow the rule of thumb. for every 2 main sizes raise clip on the needle 1. if you reach the top, time to change needles then idle/needle jet.

honestly, i always liked getting the borrom side working first, then the top end was always way easier. i use the throttle to tell me how she's runnin at low. the more responsive it at the blip, the better it's running. but! at free-rev you can become too lean and when you finally put a load on it, it runs like poo! that's where you adjust it back out jsut a tad bit and you should be good to go.

[honda250sx]

RUN IT!!!

http://i71.photobucket.com/albums/i151/brauerpower/Everfeel.jpg

[Tri-Z Pilot]

Go with a dial-a-jet man! Jet your carb lean and let the daj take up the slack. Never re-jet again, and it gives you killer throttle response. I have only used them on two strokes, but read that they work great on fourstrokes as well. Got one comin for my R. It will be on for Pennsyltucky09. I'll let you rip it, and dick around with it to see if you would like to try one in the future.

[cr480r]

Go with a dial-a-jet man! Jet your carb lean and let the daj take up the slack. Never re-jet again, and it gives you killer throttle response. I have only used them on two strokes, but read that they work great on fourstrokes as well.

Is that similar to a power jet? Is it an additional circuit that sucks from the bowl and adjust with a knob? If so I have one i got off ebay for $25.. havent used it yet because I heard it was unnecessary with gasoline.. just curious? been thinking of putting it on my air-cooled 480 and only opening it when I go to the dunes or other high load high heat situations

[2quicktecate]

i have a built 200x that runs real rich at the bottom but killer at the top end, this is how i got it. have'nt had a chance to play around with it, my tecate project keeps me too busy! i just keep a spare plug on hand when i'm out riding the x

[Erics350x]

I'm goin through similar issues with my son's 85 200x. This is the first time i've had to work with race gas. It just seems odd not being able to smell and see that pump gas black cloud when your running rich.

[Dirtcrasher]

The other thing to consider is whats the cam grind?? My cam grind is very aggressive and it feels like a topend cam. Honestly, it's about as close to a 2 stroke as an old style thumper goes :lol: this thing just LOVES to be revved.


This porting was supposedly performed by Mickey Dunlap and it's some of the best I've seen in a 4 stroke head!!

My 50 pilot seems a bit big and the 260 main is too lean for that lid being off.

There is a teenie tiny jet in the back of this Mikuni, might be called a "starter jet"?? - I'd have to look it up, but that could be my choke circuits problem too. I gotta get some more research done and head back out there to get-r-done :D

[edog]

Go with a dial-a-jet man! Jet your carb lean and let the daj take up the slack. Never re-jet again, and it gives you killer throttle response. I have only used them on two strokes, but read that they work great on fourstrokes as well. Got one comin for my R. It will be on for Pennsyltucky09. I'll let you rip it, and dick around with it to see if you would like to try one in the future.

I had one on my 225. It worked very well at fine tuning!!!!!

[userj8670]

Steve to touch on what someone else said, perhaps you need to find a balance. I know alot of drag cars with high lift cams have the idle set way high otherwise the high lift of the cam fouls the plugs (and they just are not built to idle at a low RPM. Try idling your trike a bit higher...? With the agressive cam your running you cant expect to idle all nicey nice. My corvette has a .618 lift cam @ 50 and it idles between 1000-1350RPM (normal cars are about 750rpm) - depending on the weather. Think of race cars.... Also race cams that are built for top end and 'love to be reved' will have crap for bottom end...because the cam is designed to make power at a higher rpm. Just my .02 worth.

[Dirtcrasher]

When were talking "bottem end" power, I know that there will be a sacrifice but I'm also a decent enough tuner to know that it isn't jetted right.

I'll bet 75% of modified mchines are not jetted spot on... Ya know why?? Most people are terrified of jetting changes and as soon as it's close, they say "good enough".

Take my 350X as an example. It has a 450R can with an HRC tip and an open lid. It starts both cold and hot and runs well throughout the whole spectrum. BUT, it's not perfect!! and I know I could get it better but it really runs very well and I don't dick with it. Id like to add a 400EX carb and the ST exhaust on there that I have, but I know it will be back to square one once again!!

I enjoy both riding and wrenching but I ALWAYS want one reliable machine I can beat the3 snot out of and count on it to get me home.

Truth be told, like I said above, I have been very LUCKY with jetting in the past and I think many of us share that luck! but, at 2 hours into jetting, I plan on a couple more hours before I feel I have this 200X very close to perfect!!

[Tri-Z Pilot]

Is that similar to a power jet? Is it an additional circuit that sucks from the bowl and adjust with a knob? If so I have one i got off ebay for $25.. havent used it yet because I heard it was unnecessary with gasoline.. just curious? been thinking of putting it on my air-cooled 480 and only opening it when I go to the dunes or other high load high heat situations

Yea, it take fuel from the bowl via a supply line that you tap into the drain plug. No adjustment necessary other than drastic alitude changes. Then all you have to do is turn a knob, theres 5 adjustments in all. ( 2 negative, 2 positive). The daj system uses vacuum and acoustics to deliver the exact amount of fuel that is needed for climate,mods,temp,altitude changes. Plus the fuel is emulsified before it reaches the carb venturi, so it actually travels fater than your carbs regular jets, so it gives you killer snap and resonse. Always jetted for optimum efficiency, no more meltdowns, and it's under $100.

[Tri-Z Pilot]

My machines will never go without this system ever again. The applications are limitless. Cars, bikes, snow mobiles, anything with a motor even EFI units. I suggest you read about it yourself, the article will awe you in dis-belief, and its no joke.

www.thunderproducts.com

[DeePa]

steve, find out the differernce betweenthe 4 stroke and 2 stroke dial a jets...i have 2 of the 2 stroke kits sitting in a box...

[Dirtcrasher]

steve, find out the differernce betweenthe 4 stroke and 2 stroke dial a jets...i have 2 of the 2 stroke kits sitting in a box...



Thanks for that link Pilot!!

Mike, it appears that there is a definite difference between the 2 stroke and 4 stroke dial-a-jet, I may just buy one. But I shouldn't give up so easy either and the jets I have a free and the kit is 75$ plus shipping.....

I gotta go jetting later today!!

I'm enjoying my retirement at the moment :D

[jeffatc250r]

Thanks for that link Pilot!!

Mike, it appears that there is a definite difference between the 2 stroke and 4 stroke dial-a-jet, I may just buy one. But I shouldn't give up so easy either and the jets I have a free and the kit is 75$ plus shipping.....

I gotta go jetting later today!!

I'm enjoying my retirement at the moment :D

Any luck with your jetting?

[Dirtcrasher]

Any luck with your jetting?


Another day of fun!!

Thing is, this is an old school Mikuni flatslide with ALLOT of miles on it, there is definite obvious wear on the slide. But I have a brand new one, it just doesn't have the mods to be a bolt on and I'm not equipped to do it just yet.

So, today I took my new Mikuni parts and swapped the slide, and the choke assembly and dropped the pilot to a 40.

There is still a choke circuit problem, it bogs down while choked and I can immediately take off the choke when it's cold. It HAS to be that jet in the back of the carb that I changed, it must be too big..... I need to do some reading and see what that jets function is.....

Regardless, I got it running and it took off great. So, I took out that main that measured about .057 and replaced it with a .065 jet and it still loved the fuel with the AB lid on.

I'll tell ya, .065 is a pretty good size jet and this thing is getting faster and faster every time I increase that jet. Tomorrow I'm gonna get that AB lid off and see how fat I can run this :naughty:

But I'll say it again, this 200X will blow the doors off of my 350X.... It is fast as hell and I can't wait to get it all as close to perfectly jetted as possible. IDK if it's the porting, lightened flywheel, race gas, carb or the cam, but it screws :w00t:

I can now see how a 200X stroker crank with other mods was beating 250R's back in the day - I feel it is ENTIRELY POSSIBLE!! Reliable?? Who knows, probably not with the valves flapping around and all but even if it blew yp, wouldn't it be awesome to beat a 250R?? :welcome:

I'm thinking the next one I build (if a stroker is too much work) I may just knife cut the crank and lighten it up some. I think it's the revs that launch these low displacement thumpers but it's obvious to me that they can run!!

Layed off or not, I am attending Pennsatayuckafukayuckawey and bringing this trike to play with. I just hope the conditions are decent and that I don't blow it up in the next week dicking with it :D

Dammit, I sure wish I could take a video of this thing.................

[oscarmayer]

i'm likin that dial-ajet thingy.

[The Goat]

I'm interested to see just how big his main has to go.

need to bore that intake bud

[Tri-Z Pilot]

I got my dial-a-jet today, should be installing it tomorrow. If you ride in dusty conditions, you should by the snorkel kit too. I found something neat with the kit that I dont remember with the last one. It's got an extra fitting for the fuel supply hose, and if your carb bowl has a drain screw, you take that out and put in this fitting to deliver fuel to the daj, no drilling or tapping!. I'm gonna mount the daj on the airboot right behind the carb. My R has been ported and polished,old school pipe (unshure of what it is), with a 38pwk. It's a very top end powered bike with bad transitions and flat spots between bands, so I will let you guys know how it works. I put a K&N on that was hiding in my shed, and that made the top cut out a bit, so I should be perfectly lean for the install, I will also raise the clip a spot or two.

Will be back by Saturday with results, I will start a new thread.

[Dirtcrasher]

Great! Let us know how it works. I read up on them yesterday and how they WANT it lean to begin with. And at 75$, you really can't beat the price if they work.

Did you buy it at that site and did it run you another 10$ to ship??

[3Razors]

In the copy of 3wheeling of May 1985. There is an article I have where the installed white bros 28mm flatslide on the 200X with just an aftermarket pipe. The final jetting they ended up with is:

210 main
20 slow
175 series Q-2 needle jet
5-DP-39 needle with the clip in the middle.

[edog]

http://www.3wheeler.org/vb/showthread.php?t=13184

[jeffatc250r]

Dirtcrasher, you say ya got a new carb, but dont have the means to mod it to your likings? What do you want to do to it, bore it out?

[Dirtcrasher]

In the copy of 3wheeling of May 1985. There is an article I have where the installed white bros 28mm flatslide on the 200X with just an aftermarket pipe. The final jetting they ended up with is:

210 main
20 slow
175 series Q-2 needle jet
5-DP-39 needle with the clip in the middle.

Thanks Razors.....

Makes me wonder if my 40 pilot is too much... BUT, with a 20 in there to start with, the pipe turned cherry red up by the head.

So I went FAT and up to 50. Then the choke did nearly nothing so down to 40 I went. Still there now....

Had a new problem yesterday, cutting out everywhere. BUT, I had ran out of fuel the day before and had to use reserve. I'm willing to bet that I have a dirty petcock and because I wasn't done, I'm not running an inline filter yet. I'll take it all apart and get it spotless.

I'll start with that today and go from there.


Dirtcrasher, you say ya got a new carb, but dont have the means to mod it to your likings? What do you want to do to it, bore it out?

In order to properly bolt it to the 86 manifold (without radiator hose and hose clamps and crap....) you have to machine the front of the carb with a 4 jaw chuck (so it can be centered) and build a flange to press onto it.

I think my used carb is fine, it's just a matter of jetting it right.

EDOG - Sounds like you never got that dial a jet fully tuned?? They make it sound like you bolt it on, dial a number and ride away.

I am definitely NOT cutting a hole in my AB to carb boot!!

[edog]

EDOG - Sounds like you never got that dial a jet fully tuned?? They make it sound like you bolt it on, dial a number and ride away.

I am definitely NOT cutting a hole in my AB to carb boot!!


That was old thread. I got it dialed in after a while. I dont blame tyoyu for not drilling a hole in the ab boot.

You can mount it to the carb if you are running a big enough carb.
If it's small carb it won't work well.

[1upfront]

http://www.3wheeler.org/vb/showthread.php?t=13184

Those things are junk lol do it the mans way and get alittle fuel on your hands.

[edog]

Those things are junk lol do it the mans way and get alittle fuel on your hands.

Sounds fine to me. To each there own.

[jeffatc250r]

I know a guy with a 4 jaw chuck :shiftyeyes:

[Dirtcrasher]

Thanks JEFF!! I haven't given up yet!!

So, today DEEPA came buy and thankfully he didn't hit on me this time.... GOD, it's got to the point that I have to wear 3 pairs of panties top keep him away :lol: :D J/K

Anyhow....... We toyed with it again. With the 40 pilot and the .065 thousandths jet. It would break up so bad I was honestly considering an ignition problem..... All I had done between this was to swap the very worn slide from this carb to the slide from the new carb.

So, we took off the AB lid, stuffed in a FAT FAT FAT .073 drill size and the thing took off like a jet!!!!!!!!!! It still hs limited isues down low but up high it's stupid 200X fast.

.073 - Do any of you guys know how BIG that is?? It is FRIGGEN HUGE!!!!!!!!!!!!!!!! Mike thought it was larger than the jet he has in his 250R.

It loves race gas and it loves allot of it. Honestly, I think I'm gonna blow this thing up, tuning in 20 degrees, barely getting it warm and holding it WOT!!?? It can't be good for it, but I have to learn somehow.

Now I look back to all the posts "I have this and that and where do I start" and I'll say I HAVE NO CLUE!!!!!!!!!!! Just like others have said, no 2 engines are alike and no one can tell you where to start!

It SUKS, it is SO frustrating..... I cannot BELIEVE how much richer I am now that I was at TF08. This thing was a complete DOG compared to how it is now but it still isn't right. It will take hours and hours of more tuning to get it the best I can.................

[Tri-Z Pilot]

Those things are junk lol do it the mans way and get alittle fuel on your hands.

I dont know where you got your info from, but it worked wonders for my Z.

Still have yet to put it on the R, hopin I will have time Sunday.