spannerman167 wrote:
260 is way to small for an air cooled motor it won't take long to seize if full throttle is used for extended periods.
I also have a 79 CR125 fitted witha new 34mm Mikuni VM carb
I'm starting with a 340 main and a 32.5 pilot.
I had a 80 CR125 fitted with a Mikuni VM and I had it jetted on a dyno so I'm using those jetting spec's
as a starting point.
Keihin 1.547 (marked 154)= Mikuni 320
Keihin .611 (marked 61) = Mikuni 50
Remember Keihin figures are bore size, Mikuni are based on flow.
This post was extremely helpful. Thank you. I got away from riding the 79 for awhile as I picked up a 1980, and have been working on rebuilding that.
Anyway I am back to the 79 jetting now, and your post was very informative. If you don't mind me asking what elevation were those settings for, and what temperatures. I am at 5500 feet above sea level, so will need to adjust for that. And just to be sure we are on the same page, the 340 main jet you mentioned was a 4/042 Genuine Mikuni jet, correct?
Thanks again for the information, I really appreciate it.