[TimmyB]

Hello,
I bought a Honda CJ360T brand new in 1976. It last ran in 1984. This past winter, I rescued it from my father's garage, cleaned it up, put some new tires on, installed a new battery, points, fork seals, etc. It has 33,800 miles on it and looks terrific. I also rebuilt the Keihin CV carbs. It started right up! Although it runs and I can ride it, I'm having an issue that I can't seem to solve. If it's idling and I increase the throttle, the revs shoot up they way they should, but instead of going back down to 1,200 RPM, the engine races at about 3,000 RPM. I've tried adjusting the air valves on the carbs and adjusting the idle speed screw, but nothing helps. Eventually, the RPMs go down and it will idle, but it sometimes stalls or makes "popping" sounds from the muffler. The "popping" sounds seems to make the left carb move, too. Other than that, it pulls strong and rides pretty well for an old bike. It even starts on the first kick! But this idle issue is not good. Do you have any ideas about this? I'd appreciate ANY input very much because this is beyond my level of expertise. Thank you in advance.
Tim
Syracuse, NY

 

[Bird76Mojo]

Have you checked that the spark advancer is operating properly? Also have you checked the timing?

GB :mrgreen:

 

[TimmyB]

Thank you. I'll check both the timing and the spark advancer this weekend.

 

[Bird76Mojo]

No problem man. I'm no guru like others here, but that's what popped into my mind first. If nothing else then it eliminates those possibilities. I'm just glad to lend a hand.

GB :mrgreen:

 

[leethal]

When you look at your advancer, make sure the little springs return the bob-weights to their retarded position by pulling the bob-weights out and watching then snap back in. If they dont return fully home you'll need to either replace the springs (availiable from www.mikesxs.com for $8), or shorten one of them by removing a coil and bending a new hook.
Also make sure the advancer is clean from crud, and give it a little high temp grease to smooth things over

 

[KERRY]

Check that your carb throttles close when you release the hand throttle. Throttle cable could be binding a little or not have a clear run to the carbs - vibration lets the throttle eventually return to the closed position. you might be able to check this easily with the motor not running - rotate the grip to full throttle and watch the carbs when you release it. Throttles should snap closed all the way to the stops.

 

[Greenbush]

I see this post is over a year old, so I am assuming you solved you slow rpm return. My thought when I read this is a couple things;
1)Did you forget to put the springs back in the CV slides when you reassembled? And did you make sure that the boots were put
back in the right position. There is a little tab on the rim of the rubber boots that line them up.
2)Did you change the Air Box set up? Look for cracks in the Air Box insulators.
3)If you are getting a back fire and you already checked your timing, have you checked your valve clearances?