by JJservices » Tue Feb 11, 2020 5:27 am
Need help like ASAP. I’m working on a 2009 crf250r. Before I touched anything, the bike was extremely hard to start. Hot or cold, didn’t matter. So I started with the carb. Cleaned it. No change. An ultrasonic machine was used to clean it using carb cleaner. So at that point, I checked the obvious next step. The notorious valves. They were def out of spec. So at that point I decided to just start fresh with new valves. Oem valves were used and I had a machine shop install them. Put the head back on, did the math to shim the valves into spec.
Intake....left .006, right .005
Exhaust....left .009, right .009
The bike at first started much easier. Then went right back to being a bear to start. Every once in awhile it would pop out the exhaust or backfire. So I double checked the timing. The timing I am not happy with. No matter how hard I try, and I’m pretty good with setting timing, all the marks never line up...EVER!! so I use the marks on the flywheel. Is it a common issue for these marks to be off. And no the flywheel did not spin. Anyone have any tips or pointers? Once I get it running it runs perfect. Idles smooth. I’m at a loss.