This is a discussion on Big Bear 400 wont stay running within the Yamaha Big Bear/Bruin/Wolverine ATV Discussion forums, part of the Other Yamaha Forums category; I just got a BB 400, 2009, it only has 400 miles on it. Guy I bought it from never rode it. It starts fine, ...
I just got a BB 400, 2009, it only has 400 miles on it. Guy I bought it from never rode it. It starts fine, but wont stay running. Once under throttle, it runs great. Idle is better after warm up, but still wont stay running.
I am fairly mechanical, rebuilding an old Corvette right now, but have never messed around with bike carbs. Any input would be greatly appreciated.
Check the idle screw and air filter to start. I did own the same bike and also an 2001 BB and they are very very cold blooded! Make sure the carb isn't gummed up if it sat with ethanol and no stabil. I run only ethanol free premium in mine.