Seized piston?

[Peedy17]

Hi all,

Was riding down the road the other day. Id just filled with petrol and 3% oil mix. Its a new oil i havent used before.

About half a mile later my back wheel seemed to lock and i lost all gears (later diagnosed as a stuck clutch)

Now i cant kick start it as its really stiff. Can turn the crank via a socket but a bit stiffer than normal.

Ive had the head off and back on again and i could see anything wrong.

Is this a seized piston due to bad fuel/oil mix?

If so whats my best options? Its a j125

Cheers

Pete

[St George]

What did the barrel look like when you had the head off, was piston free ? Did you consider whipping off the barrels when head was off. If it was free consider the gearbox end of the engine.

Colin

[Peedy17]

I took the barrel off. Came of quite easy. No marks and nice n shiny. What should I be looking at on the gear end? My 1st gear cog is really loose and needs replacing

[dscscotty]

what numbers your house? I'll nip in and take a look if you want?

[Peedy17]

I'm not in today mate and off to Rotterdam for a month or twos work on mon. Would be great if you could when I got back though

[TS1-200]

Crank ? a mates SX siezed, barrel and piston fine, the big end bearing had locked up.

[dscscotty]

Did you get sorted?

[Peedy17]

Sorry mate. Only just seen this reply.

Only just had chance to have another look today.

Had the gears out, put it all back together. Still really stiff but if I turn the flywheel I can see the piston moves freely

Also if I pop the spark plug out it kicks fine.

Cheers

Pete