Home
Basic Dirt Bike How-To's - Video
Dirt Bike How-To's - Video
Living The Moto Life - Video
Bike Tests | Shoot-Outs - Video
Forums
What's new
Latest activity
Log-In
Join
What's new
Menu
Log-In
Join
Navigation
Install the app
Install
More options
Close Menu
Forums
Dirt Bike Discussions By Brand
Dirt Bike Brands - Other
YZ 400 popping (lean?)
Reply to thread
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
[QUOTE="Boit, post: 123153, member: 19734"] If you are saying that the engine ran fine and suddenly started this habit after sitting up for a short period of time, I would suspect that the pilot jet is at least partially clogged. . . if not totally clogged. I ride a Yamaha Riva 125cc 4-stroke scooter to work and the thing sat up for 2 months while I recovered from a motocross injury. When I went to start it, the thing would not idle and generally ran like crap, plus it would backfire through the exhaust if I revved the engine and then closed the throttle completely. . It ran fine before the period of unuse. I found the pilot jet totally plugged with that gummy crud that pump gas tends to leave inside the carb. I cleaned the entire carb and now the thing runs better than ever. It's pretty amazing just how dirty the carb internals get in a relatively short period of time. By the way, yes, you are correct in attributing the popping to a lean condition. One source of this popping is a leak at the head pipe to cylinder head exhaust port juncture. If you've had to loosen the head pipe repeatedly, then maybe the large copper washer/seal ring may not be sealing anymore. If there is a slight leak here, you can get that popping. Since you describe a generally poor running engine at low RPM, I doubt that an exhaust leak is the culprit. [/QUOTE]
Verification
Which ocean is California closest to?
Post reply
Forums
Dirt Bike Discussions By Brand
Dirt Bike Brands - Other
YZ 400 popping (lean?)
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top
Bottom