Rear wheel locks up when trying to bump start

I have a 2006 Honda CRF 250R which I have been able to bump start with no problems up until now.  It kick starts perfectly fine and runs fine.  I have no problems with the clutch or gears when I'm riding it.  It rolls freely in neutral and in gear with the clutch engaged.  But if I roll it down a hill in gear with the clutch engaged, and then release the clutch, the rear wheel locks up hard sliding on the dirt and the engine does not turn over at all.  It doesn't matter if I'm in 1st or 2nd gear, same result.  This bike used to not do this and would instead turn over just fine using this exact method.  Any advice on how to fix this?



A little more background:  My bike started giving me more and more problems kick starting it so I checked the valves and sure enough they were worn and will need replacement.  I re-shimmed just this one time so I can get a few more hours out of them before I have to strip it down.  When I took it back to the track I still couldn’t kick start it and the kick was very stiff starting from the click so I tried bump starting it which is when I discovered my problem.  Back at the garage I found out I missed the timing by 1 tooth gear.  I adjusted and kick feels perfectly normal now and kick starts fine.  But bump start problem still exist.

Lean back and bounce on the seat to pit more weight on the tire, the ground might also be to soft to bump start

Maybe with the tight valve you had lower compression, allowing the rear wheel (engine) to spin easier. Now you have full compression and it's harder to spin? Try what yeomans suggested and see if it'll spin that way.

I just now realized something after double checking my MX log (I keep good notes). I bump started the bike on the exact same track with the same dirt conditions right before I made any adjustments to my valves. But the valve clearance is perfect right now and the timing is correct also. Again keep in mind that this bike has never done this to me and has always bump started without any problems. It's not a matter of where on the seat I am sitting, it's that something has changed here. The rear will locks up hard, this is not normal.

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