HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
sprint4425

engine sputtering..need help

7 posts in this topic

'03 yz450. new engine, Pro-circuit pipe, zip-ty carb mod. I just plated my bike and i notice that if i am not accelerating and i am in the higher RPM range at a constant throttle position then my bike is sputtering. Have no idea what it is or how to fix it.

anyone know anything about this or know how to fix it?

Share this post


Link to post
Share on other sites
sounds like a jetting issue to me

yeah thats what i figured, just dont know how to go about fixing it.

Share this post


Link to post
Share on other sites

Go back to stock jetting and start from there, never heard of a zip ty mod, what is that?

Share this post


Link to post
Share on other sites
Go back to stock jetting and start from there, never heard of a zip ty mod, what is that?

I am at stock jetting right now, i have never changed it. Zip-Ty mod is a racing modification, do a search for it on here and you should find plenty of info about it.

How big is your main jet/pilot jet?

I havent touched my jetting since i bought the bike, so the jet is still the same size that come stock. I am not really sure what the exact size is off hand, i can look it up if you need me to.

Share this post


Link to post
Share on other sites

If the sputtering seems very regular at a steady throttle, try dropping the needle one notch (put the clip higher up on the needle) and/or running the pilot screw a little farther in. If the sputter is irregular, or erratic, and accompanied by the occasional pop in the exhaust at steady throttle, try raising the needle instead.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0