By Julio Candelaria
I disassembled my engine to replace piston, bearings and seals and relied on my manuals too much. I didn't take a photo of the 3 shift fork positions and believe I have them installed properly but cannot find anything to guide me.
Anyone familiar enough that can glance at the photos and let me know if they look correct?
Photo angle is from the bottom of the engine, one of the forks has an L on it so it's obviously the left side when facing the engine bottom angle.
I'm working on the other half of the engine in the meantime, hoping to get a tip to help me feel better so I can reassemble and take her for a spin!
I recently rebuilt top and bottom end. Heat cycled it, break in, ran fine. First ride, an hour in, it died and would not start again. Lost almost all compression. Has 15 psi on compression test. I have cylinder pulled off, piston and ring looks fine. Head gasket looks fine. Tightend head studs, they were a little loose. Head doesn't seem to be warped at all. I'm at a loss. Any ideas would be appreciated.
Buckle in this is a long one. Any advice is appreciated! I have a 2011 RMZ 250 that has done me very well for 4 years. Has been a very reliable bike with lots of power.
Last year it started to act up a bit, slightly less power & became more difficult to start, especially cold (side note: it’s a Suzuki so it’s never started great cold but usually 3 or 4th kick was the case). Still ran okay though & fiddled with the fuel screw a bit which seemed to help with the starting/power issue for the rest of the season.
This past winter we pulled it apart, put a brand new piston in, checked the valve clearances, moderate amount of carbon build up on the valves which we cleaned off, and put in a new spark plug which is also in spec. Bike still wouldn’t start great cold but was starting on about the 8-10th kick and power seemed to be improved although not 100%. I’ve take it for quite a few rides now and broken the new piston in and am having more issues:
-won’t kick over cold at all but bump starts just fine
-will kick over first or 2nd kick when warm but NOT when the bike starts to get even slightly hot
-very little top end power. Bottom of the gears seem to be full power and the hotter the bike gets the less power I have in the top end
-bike began to backfire quiet a bit when hot
-won’t idle in gear when hot
Any advice on what to replace/trouble shoot next? I had a buddy tell me it could be a worn out injector so that’s what I’m looking at replacing next. Thanks!
By Kevin from Wiseco
Attention lovers of CRF250Rs! And anyone who appreciates awesome race bikes, for that matter. We have a new bike feature on Jett Lawrence's AMSOIL Honda CRF250R race bike up on our blog, for those that may want to check it out!