FLUCTUATING IDLE

For starters, I have a 74 Z1 w/ Dyna S ignition and green coils. I am trying to work some kinks out, which all seem to be minor, but such a headache. The first issue I want to tackle is the fluctuating idle. It fires up immediately. No starting issues. Idles w/o problems. Choke seems to be working good. After the bike is warm, I'll hit the gas and when returning back to idle the rpm's will be raised. Another crack of the throttle and they return to normal, well maybe. Kinda sporadic. I did read another post with a similar problem, but never heard a resolution.

I did take off the advance assembly, disassemble, clean and lubricate. It was rusty, but still seem to be functioning properly. I verified it returns to its correct position after reassembly. I may order new springs just to give me that reassurance that they are definitely good. Anything else I can checkout at this point?

Also, I think I have some carb related issues. Just in case these could be related.

Jack, The first thing that comes to mind, is throttle cables... Spec is @ 3-4 mm of freeplay w/bars centered. try that & check that throttle snaps back & you can "hear" slides go home...2nd, Hign mileage VM's some times wear carb bodies & slides at typical throttle "riding" position, causing 1 or more slides to "hang" temporarily unless snapped shut. since you've addressed advancer, & idle returns periodicaly would dismiss vac. leak,& timing. after assuring proper free-play if prob persists, pop throttle housing & check cable inners for kinks or frays. luck g

Checked for vacuum leaks? How's the sparkplugs look? If I remember correctly, the green Dyna ignition coils need ring terminal lugs on the primary side. If you're using the wiring that went to your old ignition coils on the new ones, did you crimp the terminals with the correct tools?

Also if the supplied screws with the green coils were lost, what you used may bottom out before becoming tight. I believe 10-32 X 5/16" is the correct size.

The throttle cable is about a year old. Looks good. I just replaced the handlebar controls. The throttle was sticking a little due to a clearance issue with the new controls, but it is resolved now. Snappy return! I will mention the #3 carb again, since it may be similar to the direction you are going. I synced the carbs the other day, which was my first time, but I had 0 issues. After making some adjustments I wanted to verify the sync. #3 is all out of wack. Cannot get it to adjust properly. If I adjust it while on the sync guage, it either doesn't move, or moves very slowly. I'll sync it to the other readings, crack the throttle, and the #3 is somewhere else on the scale.

It's very possible that the carbs are worn. I've had someone go through them 3 times in the past 2 yrs, but I'm about to give up on them. :evil:

I checked for vacuum leaks by spraying aroud intake w/ wd40, while engine was running. No fluctuation in idle. So I would say no vacuum leak.

Plugs are fair. Little on the rich side.

Coils have original dyna terminal screws.

****I posted this in the electrical section, since I was thinking it was a advance timing issue. If we rule that out, move the post to the carb section.