350x: Power Concerns

[thebutelr]

Two years ago I took my stock silencer off and replaced it with a supertrapp and it hasn't ran right since. It felt like i had way more power w/ the stock pipe than it ever has since I installed it. I have messed around with the jetting but have never been able to get it right. Last year I did a top end rebuild with a 10.5:1 wiseco piston & a mild grind web camshaft. After I did that it felt like it lost even more power. Its currently running a 04' 300ex carb w/ the bigger jets I had in the old 350x carb (which I've read that carb is the same size as the 350x only it flows better & has an accelerator pump) I have been tinkering with it since then and still no luck. I used to be able to run off and leave a stock warrior but now I barely accelerate with one and they eventually run off and leave me. Can someone help lead me in the right direction as to what I should do to try and correct this? I'm thinking I might just give in and have a professional mechanic take a look at it and see if they can do something with it. Any info would be great, Thanks. Later.

[DeePa]

hows the clutch? more power in the motor can cause a near worn clutch to go...

otherwise id say take the airbox cover off and see what happens. You may even need to rejet up some more

mike

[NOS_350X]

Are you jetted properly? It sounds like you keep doing more motor works and getting less power because your not putting any more fuel in the engine.

[thebutelr]

Are you jetted properly? It sounds like you keep doing more motor works and getting less power because your not putting any more fuel in the engine.
Well man I thought I had the jetting pretty well figured out but there really can't be anything else possibly wrong with it. I have tried messing around with bigger jets but it still won't run right. The clutch does feel like its slipping a little bit because it will rev up very high for a little bit then slowly work its way back down to normal rpm's plus the plates have never been replaced....... I currently have a 140 main 42 pilot stock needle clip position & stock position on the fuel & air mixture screw. The bike has a very sooty silencer which is weird because if it was really lean wouldn't it be kind of a lighter color than coal black????

[Pete]

soot= rich

[NOS_350X]

soot= rich

any exhaust will have soot. Imo 140 seems small, with just a pipe i find myself at a 142, aifilter and pipe sometimes 142 others 145, Each bike is diffrent but with your work i would say it should be around a 148-152

[thebutelr]

any exhaust will have soot. Imo 140 seems small, with just a pipe i find myself at a 142, aifilter and pipe sometimes 142 others 145, Each bike is diffrent but with your work i would say it should be around a 148-152
I have tried a 145 & a 152 and the farther I go up it seems the performance stays the same or decreases. Is there any easy way to tell if your clutch is bad or is going bad?? I'm sure it needs to be replaced since its 21 years old and I've rode it pretty hard in the 3 years i've had it. But what are the big signs of it going bad?? I've heard if its bad then it will start to creep along even when the clutch is pulled in or even if its in neutral or it gets hard to put it into neutral while its running, but the only thing I have noticed is it sometimes slipping when I'm in a high gear and I give it a lot of gas all at once. What do you all think?? Thanks.

[deathman53]

it sounds like your cluth is shot, any slipping means a bad cluth.

[thebutelr]

it sounds like your cluth is shot, any slipping means a bad cluth.
Any idea on how much new clutch plates & springs will be for a 350x? And what brand would be the best to put in it?

[Dammit!]

Loose exhaust header can cause the same symptoms of a bad clutch. It has to be loose enough to leak really bad though.

[NOS_350X]

In 99% of cases all you need to change is the fiber plates in the clutch. Take the steel plates and deglaze them by rubing them in a circular motion on some concrete. Springs shoudnt be a concern never seen them go out, shops just say that go get more money.

[Preddy05]

When i had my 1991 250x with a 350x motor in it i had that kind of problem and it was the carb. The 250x carb was smaller than the 350 carb so no matter what jets i put in it would not accelerate like it should. I tryed a 350x carb and it fixed the problem. Not sayin thats your problem just something to think about. thats what fixed mine.

[Howard]

look in the manual. you can measure your springs. the fibers just buy some new ones. the steel plates i think you mic out as well, but usually what i do if they aren't blued from excess heat i re use them. if it's something you run real hard, them might at well buy some new plates too and save your others for spares.

[TimSr]

Im not a 4 stroke guru, but it would seem to me nobody has asked the obvious question. How many disks are you using in your Supertrapp? The idea of the disks is to make the exhaust tuneable to the type powerband you are looking for, and whether to go richer or leaner on carburetion will depend on how you are tuning your exhaust. Differnt exhaust often requires retuning your carb, but different exhaust does not automatically mean "jet richer".

I also suggest reading the sticky at the top about "carburetion 101". Its seems that in the midst of all the carburetion tips everyone forgot to mention the first basic in carburetion, which is that carburetion is most effectively read and guaged from spark plug readings, not exhaust residue.

The easiest way to know if you clutch is slipping is by riding on a surface where your tires dont spin, such as pavement. If you gun it, and the rpms go up and your speed doesnt at a similar rate, its slipping, and the fibers and springs need replaced. You can usually run the same metal plates with a few fiber chnages. The best brand of fibers to use is OEM Honda.

[thebutelr]

Im not a 4 stroke guru, but it would seem to me nobody has asked the obvious question. How many disks are you using in your Supertrapp? The idea of the disks is to make the exhaust tuneable to the type powerband you are looking for, and whether to go richer or leaner on carburetion will depend on how you are tuning your exhaust. Differnt exhaust often requires retuning your carb, but different exhaust does not automatically mean "jet richer".

I also suggest reading the sticky at the top about "carburetion 101". Its seems that in the midst of all the carburetion tips everyone forgot to mention the first basic in carburetion, which is that carburetion is most effectively read and guaged from spark plug readings, not exhaust residue.

The easiest way to know if you clutch is slipping is by riding on a surface where your tires dont spin, such as pavement. If you gun it, and the rpms go up and your speed doesnt at a similar rate, its slipping, and the fibers and springs need replaced. You can usually run the same metal plates with a few fiber chnages. The best brand of fibers to use is OEM Honda.
Update on the problem: I put the old 350x carb back on and put a 152 main jet in it w/ the stock needle clip position and that thing feels like a whole different bike. It revvs so much crisper & feels like it has a ton more power, but the slipping clutch feeling is way worse now. Now when I'm going slightly uphill on pavement and punch the gas it will just rev up reallly really high but no speed gain for a few seconds then it will rev back down and gain speed. Should I check my gaskets on my header before I replace the clutch or does this sound like the clutch is the culprit? If the header was tight would the gaskets make that much of a difference on how it seals or would it have to be very very loose to make it seem like a slipping clutch? Oh yeah one more thing, now when I rev the bike up from idle or even when I'm out riding it takes it a while to go back to normal idle rpm's. What does that sound like?

[Howard]

Clutch for sure, if you can't feel exhaust leaking with your hand around the header part then it's fine i'd say. do the clutch, nothing to it.