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-   -   1999 Yamaha bear tracker 250 starting problem (https://atvconnection.com/forums/yamaha/378753-1999-yamaha-bear-tracker-250-starting-problem.html)

CurtisUN 06-06-2019 02:51 PM

1999 Yamaha bear tracker 250 starting problem
 
Hi I have a problem I can not lay my finger on lol. I got this 1999 bear tracker 250 in a trade so no historical info except for it is a not in the database for stolen atvs. The starter solenoid is bad but has a pull start. The ignition works but with old plug did not seem to have a great spark so replaced plug. Spark did increase some but not sure it is hot enough. I have no compression gauge but it will force air past your finger and suction on intake is good. I pulled timing cover and valve covers and piston appears to be top dead with line on timing chain sprocket line up with mark on head and intake valve/exhaust valves are up. The timing tensioner is 3/4 way extended so has some stretch in chain.

I can not get motor to try to start, it is like the ignition switch is turned off. But every time i have checked the firing it fires. Now I have used some starting fluid to trying to get it to cough, sputter or backfire but it does nothing.
So I am looking for suggestions before rebuilding top end and replacing timing chain.

Thanks

merryman 06-07-2019 01:55 AM

Get it turning over on the electric start. Bikes that have been laid up can be a bit reluctant, and you usually get fed up of pulling the rope before they do start. I haven't had a lot of luck with starting fluid on bikes and don't like using it as it dries the cylinder walls and leads to excessive wear, so if it won't fire up on the electric start, clean the carb out.

CurtisUN 06-07-2019 09:49 AM

Merryman,
Thanks, I have used the starter to turn it over by bypassing the starter solenoid. Don't want to buy parts until I am sure of cost of repairing. Using a small amount of fuel tried again with new spark plug this time it showed a lot of blow back from crank case but still not starting. I checked the timing, the timing marks did not match up. It was one link out. I loosened the tensioner and the chain jumped easy over the top sprocket. I think the chain is stretched to far for the timing to ever be correct. It is now showing the F on the flywheel in the center of the whole with the cam sprocket mark lined up with the timing mark on the engine head. So I think it is in time and has a little more compression now, but still not trying to start. So I think a rebuild of engine is a must with a new timing chain. But I am still at loss as to why I get no sputter or any appearance of hitting. It has spark, fuel, air, some compression and it appears in time. I should have some indication of it trying to start.

merryman 06-08-2019 02:31 AM

Find out how much compression, check valve clearances, and clean the carb out.


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