Motorcycle Repair: Running 1/2 choked, mixture problem, fuel mixture

Question
Chris, Thanks for your time.

I have a 2002 XL 100  on which my daughter is learning to ride.  On our recent outing, I was not able to keep the bike running when I closed the choke.

At 1/2 choke the bike ran OK unless we tried to open the throttle wide, then it seemed to starve.  With the choke closed it simply wanted to cut out and it was all I could do to keep the engine running when in neutral.

Any ideas?  Thanks,  Hot in Phoenix


Answer
Hi Dan.
 I want to make sure that we are on the same page here.  What I learned was that the choke is engaged when it is closed, like when you do cold startup, and open when the engine has warmed up.

If what you are saying is what it sounds like to me, then the engine should cut out after warm up when you close the choke.

If, however, what you mean is the opposite (closed being disengaged, open being engaged), then you could have a fuel mixture problem or a fuel flow problem.

Check the spark plug.  Does it look fouled, burned white (or the electrode burned off) or normal?

There could also be water in the fuel.
Is the timing adjustment due?
How about the valve adjustment?
Is the manifold tight to the engine and carb?

There are a few things to check.
Good luck.
FALCON