I have a gas gas 250 jtr. The engine has seized wont kick wont budge. Would doing the piston kit solve this or is it for the bin or new engine job

How has it seized.

Has it left outside and seized thro' rust etc or has it just nipped up while using.

If it's while using, then, a new piston kit and hone may work. It depends on whether any bore damage has been done, or if any swathe, small end or rings have dropped down into the mains.

How did it happen ?

was driving along and it made one hell of a noise and stopped tried to kick it over again but wouldnt budge. A think al take it to a bike shop get them to strip it down see what the damage is.

If it needs engine where do you think the best place is to get one been on ebay but all look rusty and bugered

It depends what you find inside. 2 main areas: upper jug and bottom end.

Upper jug:

Piston seized in bore. These engines have nikasil coating on bore. If the nikasil got scored to the point where there is aluminum showing, the bore needs to be recoated and honed and new piston fitted. In USA, the importer does a refurbished jug, piston kit where you send yours, they send replacement. If no aluminum showing nikasil might be able to be honed for new piston and rings. If the piston broke, there could be bits of nasty that fell into the bottom end. Doing just the upper jug is a relatively easy job, engine can stay in the frame.

Bottom end:

Main bearings seized, crank or connecting rod broke. Engine has to come out, complete tear down and rebuild bottom end.

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You need to figure out what caused it to seize so it does not happen again.

Common items:

No coolant

Gas with no oil

Not letting bike warm up adequately before revving too high

Excessively lean mixture

Bad water pump

Riding like a street bike or motocrosser - Trials bikes do not have big enough radiator for prolonged high stress running.

Good luck