Vandy,
Thank your for your response. A little more info on my part may help you help me. The over revving happens with no extra throttle input. It really comes on when it is on a steep grade. I really notice it when the front tire is higher than the rest of the bike. I was just sitting there with my foot on the rear brake when it started revving. The other time was on a bank where I lost traction and had to stop. The revs picked up on its own after I had let go of the throttle.
The other sticking problem is from a plastic guide piece that sticks out from the inside of the throttle casting. Is there any way to replace that piece as it has become brittle with time. It looks like it is designed to keep the throttle slide from twisting inside the bore. This even happens when the carb is in my hands off of the bike. I took a needle file and worked it down some where it had fractured off.
Any ideas as to why it has to run with the choke down? It runs fine like that but even at speed when I pull it up the engine acts like it runs out of fuel.
I read your article the other day and it looks like an interesting project but the CDI box seems to be an expensive part to scrounge up.
I got the bike from a neighbor for free and have been putting parts into it ever since. The biggest suprise so far was when the tach gear in the trans let loose and snapped off the kicker idler gear shaft. It took me severals days to break the motor down and replace the trans shaft.
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quote name='vandy010' date='Feb 16 2009, 05:06 PM' post='79616']
Hey Kieth,
with all "flange" mount carbies, it's important not to overtighten the mounting bolts or you'll have throttle sticking problems. i usually work the throttle as i tighten these bolts till i find that happy medium. it may also be possible this is the same reason for your over-rev.
as for the kick-back issue, read here...
http://www.yamahaclub.com/forums/index.php?showtopic=14559
they are the kick-back king with the std points set-up.
hope this helps.