Topic: cb450 Slow idle response high to low rpm

[cadler]

1971 cb450 I cleaned all my jets and got the thing to idle nice at about 1100rpms. I have my air screw set at 3/4 turns(could not find in the book what to set them at).
Anyway i get good response until I hit about 3000 rpms then it seems to hang there and will hang at 3000. What could this be?
Thanks
Craig

[bill440cars]

         You say that you cleaned all the jets, did you clean the carb body as well? Did you try to make sure that all the passages are clear as well? To me, it sounds like the carb pistons might be sticking (or hanging). Best thing I can say, without actually seeing them in person, would be to double check the carbs. Keep us posted, okay?

                                                    Later on, Bill 

[cadler]

Is it possible for it to be the advance mechanism?

[cadler]

I think I figured it out, the 3000rpm is the actual idle, I took it out last night for a ride got it all warmed up shut it down and started it up and it goes to 3000 rpm's. it does idle nicely at 1k only before it is warmed up.

Sometime ima dumb#$$!

[bill440cars]

         Actually, the idle speed is supposed to be 1,000 rpm. Except what I've already suggested, I'm not sure what to tell you on this. Personally, I'd stop and go back completely through the carbs to make sure all passages are clean and that the carb pistons (along with diaphrams) are in good shape (and that the pistons aren't hanging up) followed by adjustments. Then, you might make sure that your ignition advance is able to work properly and check those adjustments. I don't really think the problem is in the ignition but, I might be missing something. With the bike warmed up and choke off (with clean air filters), it should be idling at 1,000rpm.

                                                  Later on, Bill

[cadler]

I think you miss understood me. We i took it out and warmed it up idle was always 3k

I just have to turn the Idle down to 1100 from 3k.
i guess whoever owned the bike before me cranked it enough were it would not shut down
Thanks

[KB02]

Some of the older carbs did not have an idle increasing cam like the newer ones do. Could be this is the case, in which case the bike would idle much lower when it is cold. A good tune up and carb sync should help the issue as well.

[bill440cars]

I think you miss understood me. We i took it out and warmed it up idle was always 3k

I just have to turn the Idle down to 1100 from 3k.
i guess whoever owned the bike before me cranked it enough were it would not shut down
Thanks

             You're right, I did misunderstand what you'd said previously. I do that from time to time.   I do give out some good info now and again though.   So, you've got it squared away now? If so, hope you get some good miles out of that one. Take care.

                                                   Later on, Bill

[Bill Vaughan]

FYI - The initial setting for the pilot screw is 1 to 1 1/4 turns out from close.