Topic: Choke - kindda weird...

[Harry]

Felicitations!

On all my bikes until now, activating the choke on a warm motor causes the motor to stumble and die. On the other hand, the old cars I have driven have idled really fast with the choke activated. Strange, no? Would anyone know why?


Until yesterday my 500F acted like all my bikes, but after adjusting camchain, valves and timing, something weird has happened. When the motor is warm it idles fine at 1000rpm, but when I activate the choke the revs climb to 3000rpm. Not a problem, really, but I wonder what the reason for this phenomenon is, and whether others experience the same reaction to activating the choke. In my analysis, it would seem that this would happen if the bike is idling too lean, and activating the choke improves the air:fuel ratio and causes the idle to rise?

[El Taco]

I've owned a lot of old cars. Generally the choke linkage pulls the throttle a little. I'd figure you're on the right track with the lean mixture.

[eldar]

this is hard to say, I fixed my accel pump on my 78K so now my #2 runs about the same as the rest of the cylinders but I run rich, which is odd since my year was made to run lean. When you hit the choke it is not uncommon for the rpms to climb but after a few seconds the engine will usually start to sputter.