First time in the forum and I am looking for some guidance. I recently purchased a RM-250 (1996) that was very hard to start without catching it in gear on a hill. I did a compression test last night on a cold motor and got 60 PSI, next I added oil to the cylinder and did another compression test and got a reading of 90 PSI. Again these reading were off of a cold motor. I know the prior owner very well and the bike was only ridden four times since the last piston change (it was overheated once). Also after the last piston change the bike was hard to start. After pulling the jug and piston I did notice the distinct lines from the honing process at the bottom of the sleeve and the piston appeared relatively perfect. Finally, there was a large amount of carbon on the head and dome of the piston. A Little carbon/blow by between the rings. Teh piston is an oversized Weisco. Can anyone lead me to a easy starting bike. Does it just need new rings or should I also check the reed valves?
First time in the forum and I am looking for some guidance. I recently purchased a RM-250 (1996) that was very hard to start without catching it in gear on a hill. I did a compression test last night on a cold motor and got 60 PSI, next I added oil to the cylinder and did another compression test and got a reading of 90 PSI. Again these reading were off of a cold motor. I know the prior owner very well and the bike was only ridden four times since the last piston change (it was overheated once). Also after the last piston change the bike was hard to start. After pulling the jug and piston I did notice the distinct lines from the honing process at the bottom of the sleeve and the piston appeared relatively perfect. Finally, there was a large amount of carbon on the head and dome of the piston. A Little carbon/blow by between the rings. Teh piston is an oversized Weisco. Can anyone lead me to a easy starting bike. Does it just need new rings or should I also check the reed valves?
u said he rode 4 times? that shouldnt be the piston screwed then, when he overheated it he prolly burned up the ring, try to put a new ring on and see, i bet its that since its only bee rode 4 times, did he break the ring and piston in right?
your compression should be way higher than that, pushing towards 185 psi would be great. Sounds like you may have a problem with the top end, or there's an outside chance that the head gasket is bad. Take the top end apart and inspect, and/or take it to a dealer.
Thanks for all the input, I pulled the cyclender off and it is slightly out of round and the rings were shot. Since there is already a boreable liner and the existing piston is a standard size, I am getting the cyclender bored and going up to the next size piston (.020 over). I, also ordered new reeds and top end bearing. I think I will have toooooo much bike when I am done, but I can grow into it.