February 27, 20179 yr i have a 2001 gas gas 250 idling problem when i start bike and give it a rev and let go the revs seem to be staying up ive tried a different carburetor and reed valve seems ok the fuel mixture is 80/5 and when the bike is warm and i turn it off and go to start again it wont start unless i put the choke on ive changed the plug 3 time to the factory one (NGK BPR5ES) all help appreciated
February 28, 20179 yr Pull the flywheel cover off and give it a good tug up and down. Good chance the mains and seals have gone bad,
February 28, 20179 yr Author That's my next plan I'm waiting on a flywheel remove tool coming to check it. Are u able to adjust the timing on them just incase the person I bought it of was messing around with timing thanks
February 28, 20179 yr To check the mains you do not need to remove the flywheel. You are checking movement.
February 28, 20179 yr Author ok thanks will do that tonight and let you no but it seems like its sucking in air from somwhere so ill check the crank seal when the tool comes
March 1, 20179 yr Keep in mind you can still have a ''Bad'' main seal even if crank shows no visible slop...
March 1, 20179 yr Author sorry only getting to reply now but ive re jetted the carb checked reed vavle cyclinder compression checked the timing and replaced the reed valve rubber and the bike is a bit better but its now missing/back firing any help?
March 1, 20179 yr Author im just wondering would the voltage regulator module or this we thing in picture cause this or cdi unit?
March 1, 20179 yr 45 minutes ago, monkster said: just so i no it was jetting and carb was working properly Not trying to be a smart ass, but where did you get your "proper" jetting figures from ?
March 1, 20179 yr Author i got the proper jetting from gas gas uk " the ones they said they use on the bike from factory" and theres no play in bearing "pulling flywheel up and down" and tested seals by pressurising the hole engine
March 2, 20179 yr Pressurising the engine does not necessarily prove the seals are OK. The seals are designed to seal tighter with crankcase pressure. It is when the crankcase is at negative (relative to atmospheric) pressure that worn seals allow air in. You would have to create a vacuum of at least 22 inch mercury to assesses the seal effectiveness.
March 2, 20179 yr And how did you pressurise the engine, im intrigued 5-10 inches of mercury would be more than sufficient btw Edited March 2, 20179 yr by faussy
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