As stated, I have a 1975 Honda XL 250. It has a 1 cylinder 250cc ~24hp carbureted engine. The problem I'm running into is an inconsistent idle. In general it seems to have a low idle (what I want it to idle at), and a high idle. Sometimes it will kind of stick at a high RPM and I'll have to open and drop the throttle real quick to get it down to where I set it.
This gets much, much worse when it's cold out. Riding it just now, it was at 2000 rpm for the low end, and most of the time would stick up at around 4000 rpm. And it gets worse the colder it gets out. I've had it going crazy at over 6000 rpm. Seems the colder it gets, the less my technique of opening and dropping the throttle works. I've had to adjust my idle screw on the fly just to get it to go down to an acceptable idle.
I have absolutely no idea what can be causing this. I recently cleaned the carb and rebuilt it with all new needles and everything. Any help is greatly appreciated.