Hi - long time lurker - first time poster...
I recently finished a successful valve job on a CRF230F and decided to do the other bike (CRF150F) right away because I already had all the right tools and such out. Ha. Well, my surprise is that on my 150 when I use the crankshaft nut to find top dead center, right after I see the "F" for "firing" in the sight hole and I'm ready to turn a little farther to get "T" to "top", the motor wants to slip past the "T" rather than letting it stop at the "T" point. The 230 didn't act this way. It was happy to stop at the "T" for me. On the 150 I found this behavior both on the compression and exhaust strokes. I could have a helper hold it at "T" for me, but I'm wondering if this is a sign of something else. Thoughts?
[BTW, the reason I"m wondering about other possibilities is that while the 150 runs fine at least when it's warm, I find that when it's near idle and cooler that sometimes I hear it "stutter" when I'm just adding a tiny bit of throttle above idle. The stutter is pretty pronounced and seems like the engine isn't very happy - but as it warms all seems fine.] Dunno if this is a typical kind of behavior or if it might be a sign of a timing chain issue of it being stretched or slipped/skipped and if the above symptom is just another thing pointing to that problem.
Thanks!
bob