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Hi , This is my first 250r so bare with me. I was wondering how much to report a cylinder after a big bore is installed , that looks to be kinda butchard up. Also i just purchased a 310 big bore, Its an LA sleeve kit. I was told a lot of bad thinks about the big bore sleeve in stock cylinders , like the water jackets get real thin and develop problems. If i had my local machine shop put the sleeve in, Is there anything that i should tell them to do , or is this a job for a proffessional quad guy. thanks
 

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Hi , This is my first 250r so bare with me. I was wondering how much to report a cylinder after a big bore is installed , that looks to be kinda butchard up. Also i just purchased a 310 big bore, Its an LA sleeve kit. I was told a lot of bad thinks about the big bore sleeve in stock cylinders , like the water jackets get real thin and develop problems. If i had my local machine shop put the sleeve in, Is there anything that i should tell them to do , or is this a job for a proffessional quad guy. thanks
leave it to the pros!!!!
 

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The problems with a stock R cylinder with a big bore sleeve installed are, once you remove that much metal from the casting the jug looses some strenght + the head, where the studs go through is just to thin to begin with then you get movement, slite but still movement.
Only way I have gotten them to survive is with the use of Three Bond 1211 sealant & the Cometic fiber gasket. With this fix, still its just a mater of time before it leaks, but it is an amount of time. Some I have seen leaked as soon as the engine got hot.
Normally what has happend on mine, compression leaked past the gasket & then would build up higher presure in the cooling system & would blow coolant out into the holding tank. Crazy part, no coolant would get into the cylinder bore & once the bike was off & cooled down, the coolant would be drawn back into the radiator when restarted, crazy.

Cylinder porting starts at $250.00, thats to re-port one or one thats had no port work done at all.
Upper midrange to drag porting is higher because of more work involved.
The butchered cylinder, depending on how bad the porting is now, how the port work will end up. Could be some places I cant fix if its been cut to deep.
Neil
 
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