Ec 250 Overheating New Piston?

[Elliker]

Just had load of new gaskets fitted on my 1997 ec250, head gasket, cylinder gasket, water pump gasket etc, after it kept overheating, the impeller was working fine so that wasnt the problem, just got the bike back and took it for a run and same happened again (cylinder expanded and nipped the piston,) usally i would let it cool down and it would fire up again but this time nothing, and there seems to be lees compression, so im thinking the rings have gone? which piston is it i need? does any year cr250 one fit in? also, does anybody know why the thing keeps overheating? also there seems to be a little water in the oil, maybe impeller seal? (if thats what is called) sorry for the essay but really need this sorting,
tia!

[Steve@Motowest]

Water in the oil is sure sign of leakage, most often the water pump seal but it could also be a failed side cover gasket or a warped side cover near the water pump. Also look for a warped cylinder head and/or cylinder allowing combustion gases to get into the cooling system. This may be tricky to see but a engine machine shop can check it for you.

There are some Honda pistons that will work but why not use the correct GasGas piston?

[mxdj2003]

did you check to see if you might have a clogged radiator?

[Elliker]

thanks, but here in england i dont think i can get the gasgas piston? yes checked radiators there fine, any other ideas?

[Steve@Motowest]

That doesn't make any sense, all the manufacturers have representation the UK. Have you checked with John Shirt and Vic Eastwood and Apico and Wossner?

Originally Posted by Elliker

thanks, but here in england i dont think i can get the gasgas piston?

[mxdj2003]

you said your impeller looks good but are you sure its not stripped out on the shaft , check the same thing with the impeller drive gear. a weeping water pump seal wouldn't make it overheat as quickly as you described, a quick way to check if you have an internal head gasket leak is to just pop off your radiator cap and start your bike , if your bleeding off compression into the cooling system you'll have a gyser of coolant come out of the radiator neck DO NOT TRY THIS WHEN THE BIKE IS HOT THOUGH.

[Steve@Motowest]

We should have asked this first but I are sure it is overheating? And why do you think that?

Any chance you missed adding oil to the gas? It's very common, we see it all the time in our shop.