mancat wrote:
Mancat , please define ' overheating ' as the only time valves can possibly cause hot running is of they're too tight and i know you cold set them to .002" .


It's definitely running too lean. This has been confirmed now. Spark plugs came out a little burnt recently, and it has always had what sounds to be a bit of a ping. Timing and points are spot-on. I went ahead and adjusted the valves to .003 (yes, they were previously at .002) just as a test run to eliminate any overtight clearance - valves were a little chattery, but the bike still overheated and seized up (never seizes hard) on a WOT hill run.

I already ordered the DrATV carb rebuild kit with 65 and 75 jets.. b52bombardier informed me that some 1970 California CT90s had a 62 jet, and lo and behold mine is an early 70 K2 originally sold in Oakland CA (still has dealer stickers on it). I haven't taken the carb apart again (forgot to ID the jet the first time I had it apart) but I wouldn't be surprised to find a 62 jet.

Never had the heating problem when I first got the bike and it was still ~30-40 deg in the morning and evenings. Now that it's into the 70s, it's very touchy on the road. Can still put around on trails as long as I want.

I won't expound on this any more and fill up this thread. Just wanted to answer your question.
Be sure to flatten the flanges on the carb and intake too, they could be warped and leaking air. Get access to an ultrasonic cleaner if you can... it will get everything nice and clean///



Candy Ruby 1970 CL175
CM200T "Prewar" custom
Vancouver, Washington