A couple of CJ360 questions

[Bob_M]

I have a 1976 CJ360, which appears to be identical to a CB360 in regards to throttle and carb hardware. The bikes idles smoothly at around 2000 RPM, but that is higher than it should be. Even though I've adjusted the mechanisms at the handgrip and carb locations, I can't get it to idle any lower, with one exception. If I grab the throttle grip and turn it backwards with some force and hold it there, the engine will idle smoothly at a much lower speed (about 1200 RPM). But if I let go of the throttle grip, the idle speed will creep back up to 2000 RPM.

I don't know the history of this bike, and the previous owner said the speedometer is a replacement unit and the mileage of the bike is unknown. However, I suspect the throttle cables are original. So, my question is whether a new set of cables would likely allow me to cure the high-ideal speed problem. That is, could worn cables make it impossible to set the proper idle speed? Or alternatively, should I spend more time adjusting the mechanisms? I have to admit that I've never tried to adjust the mechanism near the carbs with the engine running and the gas tank removed, because that would involve rigging up some way to supply gas to the carbs (with the tank removed).

I had another question regarding the guestimate of the mileage of a bike like this where the speedometer has been replaced. The previous owner did some quality repair work to the bike just prior to selling it to me. He replaced the kickstarter shaft because it was sheared off within the cases. This bike is kickstart only. He replaced the camshaft chain. He also replaced the front countershaft sprocket and the chain. I presume he replaced the front sprocket because of wear but I don't know why he replaced the chain (maybe rusty and not worth time to clean it up). I replaced the rear sprocket solely to change the gearing. The teeth of the old rear sprocket don't appear to be in bad condition though. I can't say if it's the original rear sprocket, but it's definitely the type fitted by Honda (it has the black "guard" plate that is riveted to the sprocket). I was intending to replace the rear wheel bearings, but they looked to be in good shape and are the sealed type (so presume they are not the original factory bearings). If the old rear sprocket was the original one from the factory, would anyone care to offer a guess of the mileage of the bike? Thanks very much in advance.

 

[ancientdad]

Moved your post to a new thread for you to get proper attention to your questions.

First, have you adjusted the idle speed knob shown in the pictures below?

this view of the knob from the bottom of the carbs

If not, that's the first place to start. There is the possibility that the PO didn't get the slack adjustment correct on both the pull and push cables and that is where the issue is, but try the idle adjustment knob first.

As to the rear sprocket, if the chain and front sprocket are changed at the proper interval (before excess wear on the chain starts to wear the rear sprocket, front sprockets typically wear out sooner) then it's possible the rear sprocket was original, but it could have been replaced back when these parts were still available at a Honda dealer since many decades have passed. As an example, my CL450K5 has what I believe to be the original rear sprocket for the same reasons you mentioned, and my bike had 14,500 miles on it. I'm still using it because the wear on it was very minimal (barely discernible by eye) and the bike now has over 3000 miles more. That sprocket will be fine for quite a while yet as long as I keep up proper maintenance. So it's possible for the original rear sprocket to last that long if maintained well, but there's no way to be completely sure in your situation.

 

[Cycleranger]

Howdy!
Aside from what AD says another thing to check is the cable routing. Improperly routed cables can cause problems.
Here's the cable routing diagram from the setup guide.
Oh and about that idle adjustment knob, I've seen several of those that were damaged.
The "cable" there is just a spring and sometimes the knob gets turned until that spring breaks.