Thread: stumbles if throttle advanced slowly..?

Hey all, me and my daughter are thoroughly enjoying some ride time on my 70, ct70. I'm still working out some issues....of which it has many. One of the more confusing (for me) issues is that the bikes starts and runs fine. HOWEVER, if i advance the throttle very slowly, it stumbles just before it picks up...to the point if i hold it at the stumble point, it can kill the engine. If i just twist it normal speed...it revs up NO problem.

I'm a little stumped on this. Any ideas?

Also, the bike runs very smooth in 3rd at 20. Above that it gets vibratey. I'm assuming this is normal? It's not like i think it's about to fall apart...just there is a gradual and noticable increase in vibrations as i accelerate past 20.

(some info...new points timed as perfectly as i could with a meter, new condenser)

Have you tried adjusting the air screw on the carb? You could also try adjusting the clip on the throttle needle up or down. Either one of these adjustments will either enrich or lean out your air to gas mixture through the carb. Check your plug and see what it looks like. If it is whitish on the tip it is too lean.

I think Hondaman is right on I'd check the idle adjustment maybe screw the screw in a half turn or so. You might even check the pilot jet to see if its clogged up with junk or something. That would make your bike do whats its doing. IMHO Good luck to you and your girls.

thanks for the replies. I did do that - in fact i tried many different settings. I'm wondering if this is an air leak issue....there is a lot of dry rot on the rubber boot to the airbox. Maybe?

I doubt that is the answer. An air leak between the carb and manifold would be a different story though.