u/Dry_Date_2730

KTM 125 2stroke very sensitive to temperature

Hello, is it normal that early 2000 production 125cc 2stroke with Keihin carb are so sensitive to temperature that I can't even believe it? It is slowly starting to anger me, when I see my buddies with 300cc run same jetting all the time and it runs great.

For example:

15 celsius - I set perfect jetting. Next day 20 celcius - Smoking a lot, doesn't go at all, sounds like too much fuel = gotta change main jet, needle by half clip with help of washer. Also pilot jet, but I dont care about that much, since I ride high RPM

Next day 26 celcius - guess what? Rejetting. and it goes on and on

Idle is too low - I fix it mid ride and then I ride more agresivelly and it changes idle so much, so I have to turn it down. After few minutes of engine cooling idle needs to be rised up again, so it doesnt die

Got to a point where I have table with temperatures 0-30 celcius and jetting settings and I need to change it before 80% of rides. It doesn't take much time to rejet when Im changing only needle and main jet, but still..

Thanks for clarification

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u/Dry_Date_2730 — 2 days ago