Posts
45
Joined
10/14/2023
Location
USA
Edited Date/Time
3/21/2025 6:17pm
Have a 2000 RM125 and noticed it had a pwk38 with 2 vents and wasn’t an air striker. So I got a pwk38 quad vent air striker and jetted to PC specs. Bike now rips and is crisp
Major issue im now having. It detonates real bad under full throttle from mid to high rpm when I was doing pulls with it. It continues to pull but the engine starts making strange noises - like a fast paced ticking/crunchy noise.
Guessing I’m either lean on the main or because I’m running 93 pump when I usually run 93/c12 mixed in half. Bike does have thinner base gasket for more compression.
Tell us the complete jetting specs, including slide #.
I’m running..
175 main, 50 pilot, R1469L needle, clip in 3rd position from top, air screw 1.5 out. Brand new Keihin pwk38 air striker, non power jet
93 octane pump/36:1 klotz super
PC jetting is based off running race gas… if you
are not running race full richen carb settings then wirk your way down leaner….or run race fuel…
You say you increased compression, have you tested to see what the actual compression is? I would go back to 50/50 93/c12, especially if you start raising compression much. I have a KX250 that has 210lbs of compression and if I run straight pump it will detonate and is very noticeable when the motor is under a load. If I run 50/50 93/c12 all is fine.
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I dumped out the gas this morning and put straight c12/klotz in. Noise/detonation is totally gone throughout now. Guess it was a fuel issue and not jetting
^ Yep, you needed a little more octane. Detonation is like that; your engine will only pull the octane as it needs it. You might find that full throttle going downhill is fine, but through mud or between jumps when you're accelerating, it will ping, tick or click. In this kind of scenario, it isn't jetting; it's octane. (They are inter-related, of course; you could go up one size on the main and fix it, but that might make you a little rich in 3/4 throttle situations.)
Post a reply to: RM125 detonating BAD with new carb.