Got a old89 350d i use as a backup or to ride when i dont care about anything. It started sputtering alot lately,
ive cleaned the carb twice, changed plugs, checked choke cable & the engine was rebuild a year ago so it doent
smoke & has good power, it accalorates good but sputters at constant speed.
Im thinking maybe some of the many hoses going to the carb (smog stuff i guess) may be a problem and could be
bypassed, i dont have a service manual so im not sure which could be pluged or removed. Maybe someone has
worked on this problem in the past?

 

check the carb needle

 

At what throttle position does it sputter??? 0 to 1/4? 1/4 to 1/2? 1/2 to wide open??
The tubes are just vents. Check them to see if they are clogged.

 

How long has the gasoline been in that tank? Did you put stabil or sea foam in , when the gas was new?

 

If it had bad or old gas in it, it wouldn't rev at all. It would die as soon as you give it throttle. I don't think it is an old gas issue.

 

If it is a metal gas tank you could have some rust in it that is not letting gas to flow correct.
You might clean tank & put inline filter on it.

 

It seems to across the throttle range, it accelorates good so i dont think its a gas supply issue. I have noticed
it seems to idle way high when cold then really drops down & have to adjust the throttle cable when it warms up.
It seems like a automatic choke that drops out when it warms up, engine is in good shape so i really cant figure
out whats going on. Anyway it reminds me of a 2 cycle, accelorates good but dosent like to run a constant speed.

 

Hi Chuck,

Did you ever find a solution to your problem? I have exactly the same symptoms in my 1991 TRX350.

Thanks
Paul

 

Another thing to check is the valve clerance's, they may be off spec's , only a sugguestion but i've seen this problem before on rebuilt and even new engine's right out of the crate....................williebee

 

No paul i never did, i rebuilt the carb several times & i think i will check the valve clearance next. Like many other
riders i have several other ATVs & have been using my Suzuki King quad 300 so i have forgot about the TRX, but i
need to get back to it, changing all the gears in the suzuki in wearing me out. The 300 is great but it requires you
use the hi,lo,super lo ranges where the TRX350 had the power to do it with only 1 range of gears.