View Full Version : I NEED HELP!!!!86 yz250

03-18-2010, 08:36 PM
ok i just got this bike from this kid 86 yamaha yz250 ..now he was telling me that he was out rideing it evrything was good,he whent to take it out the next day and the kicker wasnt moveing like it was jamed or somthin ..now we were trying to see why it was doing that were thinking the engine is seized..so he juss gave it to me, now that i have it home i took out the spark plug to see if it kicked and did but when i put the spark plug back in it dont and if it does its realy hard eny one kno what can this be..i juss want to get this thing up and runing now that i got me a bike for fee

03-19-2010, 07:33 AM
Just a wild guess, but that would sound like the exhaust valves are shut and not letting the compression out. When plug is out, the compression can escape out the plug whole.

03-19-2010, 09:56 PM
what do i have to do to fix it.?

03-20-2010, 09:14 AM
That is a bit over my head... I'll see if I can get some others to answer. I would guess removing heads to verify valves are functioning / moving, or get someone to compression test it.

12-27-2010, 12:08 AM
I know this is 9 months old but here it goes. The YZ is a two-stroke motor - no valves. Sounds like the bike is the victim of a teenager. Yur best bet is to redo the top-end(piston-rings-etc.)and hope that's the only thing wore out in it. Good luck- Jeff