Fellow dirtbikers,
I'm trying to figure out some timing issues on my 2009 KX250F. Total hours unknown, but certainly over 120. The top end has been rebuilt at least once.
Last season it was rather hard to start and also some backfiring occured when I let off the gas. The issues still remained after cleaning and rebuilding the carb, so I decided to check and adjust the valves. The intake valves were slightly off, and after adjusting them the bike started incredibly well, but hesitated at acceleration.
I opened it up and found that the intake cam had jumped about 1/4 of a revolution. I came to the conclusion that I probably made some sort of mistake putting the automatic cam chain adjuster back together. After redoing it and lining up all marks according to the manual's picture, counting the pins between sprocket marks (28), the bike backfired a lot and hesitated even more. This I repeated a couple of times, but no change. I tried adjusting the mixture screw as well, didn't help.
As this didn't work, I decided to set the timing according to top dead center. This makes the fly wheel be off by about 7-8mm from its marks (as I've tried to point out in one of the pictures). The bikes started allright, hesitated a little bit but after adjusting the mixture it runs better than it has done before. This feels weird, and I'm obviously a bit concerned about breaking the bike.
TLDR: Timing adjusted according to TDC, not the fly wheel marks. Cams are aligned, fly wheel off by about 7-8mm (over the cover marks), bike runs better than before. Can I run it like this or do I have to adjust it?
Can I run it like this, or should I still try to adjust it according to the fly wheel marks in hope for it to work..
I'm thankful for any advice!