2010 Rm-z 250 unkown problem - Need Help!

so here's all the details i can give.

i did a top end rebuild on the bike (piston and rings) - Valves were booked into the bike shop the week after, during this week i ran the bike in. (it was raining the day i was home and able to ride).

Took the head back out and sent it into my local dealer and when i put it back into the bike - she was a no-go'er!- cam timing is perfect, my mechanic came round and checked it out for me, I replaced the coil, and spark plug, and still have spark. i kick the bike and i get a backfire every so often, and it shoots a hell of a flame!

just wondering if anyone has had the same problem? or knows how to fix it?


Think about it. If it backfires-it got spark and it got fuel. Timing is off. Could be bad can chain tensioner,cams reversed,sprocket flipped,valves not shimmed right,piston/rings in wrong,leaking valve seal or seat issue. For the engine to fire everything must happen in proper sequence.if you have Skype let me know and I can see if I can help.

Valves out of time in reference to bottom end - make sure bottom end fly wheel is on timing mark at TDC - sounds like exhaust valves open at wrong time

Valves are good, got hold of a suzuki "scanning tool" and problem was diagnosed as an electrical problem, taking it into the shop for repairs tomorrow :)

Please post up what problem they find…very curious

not buying the electrical issue

My bike did the exact same thing with a leaky valve. A compression test will tell you if you have a valve/piston and rings issue.

Have you tried to bump start it?

Magneto was not charging from previous overheating issue fuel pump wasn't putting pressure behind the injector? Didn't sound right to me but that's what the mechanic said, and it works now so I'm happy.

Good find! Thanks for sharing…with the electronics on the bikes these days, that makes sense to me!

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