Recent content by Jacob 'Berg

If you can kill the bike with the kill switch it is likely you have an air leak somewhere. Stator side main seal, air boot, etc. If you cannot kill the bike with the kill switch, it is caused by pre-ignition in the combustion chamber.

I would also add that two exact same make, model, and year of bikes may not jet up the same. Do real world testing and do not rely on other people's settings. Too many variables.

Buy and try a 172 main. Also, adjust the needle clip position. All of the settings I see are clip #3 position. Clip position changes can make a big difference. If you see improvement but run out of clip positions, try a shorter (richer) or longer (leaner) needle. Make one change at a time...

If it is caused by a rich condition, it could also be that the needle seat in the jet block is worn (ovalized).

White smoke can also be caused from water vapor or coolant in the combustion chamber. Be careful with leaning out the main that many sizes trying to address the issue, especially if you are riding the bike on the road. Smoke may become the least of your worries.

Jeff, You are correct about the KX250 mud guard. I replaced this part (several years ago now) on my '05 300 with the KX mud guard. Fit was spot on.

I like to run vertex (or S3), which is a cast piston. Wossner if you prefer to use a forged piston.

Looking good Jeff. Your efforts are much appreciated!

+1. If it is going through crank seals in an hour do not wait to split the cases and replace the bearings. ie. I would not continue to run the bike, or you will be replacing more than bearings. Crank may need new conrod and big end bearing if it has not been done, given the bikes age. Cheap...

Invest in an hour meter if you do not have one.

Yes, compression should be higher. Regardless of current compression, the top end should be replaced if you are unsure of running hours and have two seasons or riding on a used bike with unknown hours on the piston and rings. Take a compression reading with the fresh top end so you have a...

I'm surprised you ended up with the 170 main jet with the NEDW. If power is a little weak at larger throttle openings, try the 172.

I would prefer to ride a carbureted bike. This is not good news for me. I just wanted to share what is happening with the future of the Rieju bikes. Likely we can buy the new bikes and fit up a Keihin.

https://enduro21.com/en/features/latest/valleys-hard-enduro-hewc-rnd1-paddock-spy-more-spark-for-jonny-and-fuel-injected-rieju-s

I had good luck with sending out my stock head to RK tech for machining. Your best results are going to be taking a squish measurement and talking to a good machinist about tightening up the squish band and getting the dome cut for the fuel (or compression ratio) you prefer to run, as others...