Seized Piston

bgoates · #1 (**permalink**) 04-09-2008, 03:53 PM

Lately my motor seemed to have lost power. Today the piston seized. I took it home, took off the head and taped the piston and it came loose. Put head back on started up and minutes later seized again. I don't think it is because I'm running lean because I mixed 25:1 and spark plug, piston, and cylinder are all black. Anybody have any solutions before it seized permanently ?

Thanks

**Bikeguy Joe** · #2 (**permalink**) 04-09-2008, 03:59 PM

How many hours on the engine?
Excessive carbon build up? Sticking rings can cause a seizure.
Are you absolutely sure the plug itself is black? That would be too rich, not a cause for seizure.

VENICE BOY · #3 (**permalink**) 04-09-2008, 04:47 PM

I would say to take the barrel off too & look at the rings & piston skirt & inside the barrel.
Look for ANYTHING that doesn't look right...how do the rod bearings feel? any exessive play?
Tell us what you find!

bgoates · #4 (**permalink**) 04-09-2008, 05:15 PM

Yes the plug is black. How do you take the barrel off ?

VENICE BOY · #5 (**permalink**) 04-09-2008, 05:29 PM

With head off & the engine out of the bike, slide the barrel straight up off the piston.
You might have to (CAREFULLY)tap it loose with a rubber mallet, don't break the cooling fins!!!

bgoates · #6 (**permalink**) 04-09-2008, 05:55 PM

I got it started again and ran a few km's but kind of hesitant to take it for a good spin. Is there anything I just could spray into the cylinder to clean out all that carbon without taking everything apart ?

**Bikeguy Joe** · #7 (**permalink**) 04-09-2008, 05:56 PM

Yeah, see if there are any vertical marks on the cylinder liner or piston...may be a wrist pin bushing that went bad....how many hours on it?

deacon · #8 (**permalink**) 04-09-2008, 06:57 PM

Tell me you torqued the head bolts carefully.

I have a question though. If the cylinder walls are scored, wouldn't that mean the compression would be down too much for it to start at all. If so he can rule that out since it did start again.

deacon · #9 (**permalink**) 04-09-2008, 08:24 PM

I have one more question did the motor lock up when the piston seized.

bgoates · #10 (**permalink**) 04-09-2008, 09:58 PM

Yes the motor locked when piston seized and tire skidded.....I don't have a torque wrench so just tightened with a socket wrench.

If I'm running rich do I move the clip on the carb needle up or down ?

Should cylinder and piston be black as coal ?

I think my compression is still good...

Thanks for your comments.....