Has anyone encountered this? My bike starts easily and runs great. When it's cold, I just kick it once, and it fires up and revs to about 6000 and holds there. I let it warm a few seconds, then put it in gear and put some load on it and that brings the idle down. Once it is warm and running, I have the idle set up nicely, ticking over at less than 1000.
The engine is about 20 hours in since a rebuild. During that time, I have adjusted idle and mixture screws according to Ed Moore, adjusted float bowls, checked valve adjustment, fiddled with anything else I can think of.
ideas?
High idle at cold startbut if it's hitting six grand then he'd have to be whacking the throttle way open during his standard starting procedure for the slide(s) to get stuck that far open. ? maybe read over this thread.. I've had bikes that did something like this (but not revving quite that high) and I always assumed it had something to do with a leaky petcock or float because it only happened after it sat for a week or so. It was like there was a puddle of gas somewhere in the intake and once I started the bike it had to burn that off. If it just sat for a few days then no problem. That thread seems to say it's a lean condition from the gas sitting. I've also had bikes with vacuum leaks that would rev uncontrollably and sporadically, but that continued long after starting.... I would go through and check for air leaks as well. Sometimes things don't sync up as well as you thought when bolting on. Could be thin enough that the space gets taken up as the bike warms and expands.
I found alot of times with odd carburetion, it just takes going through everything again and inadvertently fixing whatever the issue might have been by basic tuneup procedures, or reinstallation. Old bikes don't have the same tolerances they did when they were new, leaves alot of room for quirkiness. As mentioned, also check to make sure your screws aren't tightened too much to the manifold, easy to warp the slide body. All just a guess based on my experiences. Current restoration: 1962 CB77
http://www.flickr.com/photos/1962_cb77_restore/ thanks for the responses, definitely need to go through carbueration again. I don't open the throttle all the way up during cold starts, or I would have assumed that the slides just weren't operating fully when cold. But I had eliminated that by just observing them with the filter tubes off, and confirmed they were closing all the way.
That said, today I fired it up, and the engine started racing as usual. I tried unscrewing the idle adjustment, and sure enough, the revs started dropping. But, as I predicted, once the bike warmed up, I had to screw it back in in order to get a normal idle going. But I seem to have other carbueration issues. About half the time, the bike starts only one one cylinder. I have found some crud in the petcock filter, and at least once had an obstruction in a main jet. I also am having a hell of a time getting the right float bowl to stop leaking. So not only is it not sealing, it looks like it is overfilling as well. More tweaking...
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