cb 360 wont idle when warm right leg getting a workout.

[tonuppirate]

so i've cleaned the carbs checked for air leaks all seems well, and when cold she will idle for days. but when i'm on the road and she is all warmed up, whenever i close the throttle she just dies. i'm runnng keihin carbs on her for now but when i get a few bucks i plan on switching on over to 32mm mikunis. i dont have the ability to sync the carbs, and none of the local shops are willing to do the job !?!?!?!? yeah i know! the response i got was we don't work on bikes that old! but i'm not sure its a sync problem anyway as there is no hesitation or faltering and throtle response is instant. but heck i'm no expert. any input is appreciated
thanks

 

[Big R]

If the shops won't work on it because it's "old", point out the fact that just makes it easier to work on.
Sounds to me like it's either running rich or the coils are old and over heating.

 

[tonuppirate]

running rich could be possible i guess, i have, i believe the stock keihin jets 100 and 68 respectively with an aftermarket pipe and k&n filters. though i would think that would make it run toward the lean side. have never needed to use the choke on a cold start though. I wouldn't know about the coils or how to check them. hints on that would be appreciated
thanks

 

[Erch]

have never needed to use the choke on a cold start though.

Sounds rich right there. Let it sit at idle as long as you can without touching the throttle, let it die and check your plugs: even good idle circuits will foul plugs a bit but your`s should be quite noticable if they`re that rich.

Edit: also could be bad timing, that usually masqerades as a rich or weak spark issue. Could also be worn or broken springs on your mechanical ignition advancer: with no tension to retard the timing at low rpms, you could be sparking too fast when you come down to lights. Are you hearing pre-ignition pops at all before it dies.

I wouldn't know about the coils or how to check them. hints on that would be appreciated
thanks

Most manuals will tell you the only way to check a bad coil is to swap it out with a good one and note the improvement. Usually though, you can tell the difference between it and fuel mix quite easily: fuel mix will hit you as soon as the bike is up to temp, whereas coils will take longer and especially start up if you`re doing highway riding. You`ll notice it capping off at higher rpms and in the worst case scenario it`ll just cut out on you, but usually not when you come off the throttle like you`re experiencing.



In the meantime the cheap fix would be just to turn up your idle set screw. You`ll burn a bit more gas and the engine will stay generally hotter in stop and go traffic, but if it works you know it`s your fuel mix.

Your greatest tool here is going to be a spark plug wrench. Your plugs are going to tell you everything about your fuel mix and if your spark is lousy.

 

[tonuppirate]

pulled plugs and they are black also noticed they were a little out of spec so i regapped them per the owners manual (yeah i got the original owners manual when i got the bike, cool eh?) lets see, i upped the idle and took it for a good 10-15 min hard ride, it did not die once, but i did notice some popping on decel. prior to my changes the bike would almost always start having problems immediately out of the gate, and when i bought the bike a couple of weeks ago i rode it 70 miles home, even then it occasionally died at idle. i figured bad gas at the time. but if it was a coil issue i probably wouldn't have made it home at all traveling at 70+ mph speeds.

lets see, what else, the battery, I measured the voltage and got 11.4 volts. that could be because of all the idleing and short rides and flogging the starter button when i got tired of kicking the damn thing. or it could be going bad. since I want to relocate and use a smaller battery anyway I got a new one, sealed gel type (12v 8 amp-hour 190 CCA) with a much smaller footprint so I can mount it out of the way. But I need to build a battery box for it, probably tomorrow or monday.

so we are down to carb problem = too rich , or
bad battery = weak spark

BTW both plugs seemed to be fouled equally if that makes a difference

your thoughts?

thanks