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Hey guys this isn't my 1st time posting on here but I have a question I just got this 87 trx250r off of a guy that won it in a raffle so he didn't know nothing about it and then the guy that raffled it didn't know nothing about the motor it. So I ran it at Ironman and quickly realized the jetting was way off. It had a stock 34 pj carb with stock jets in it. I did a quarter of a lap and parked it not really worrying about it because it was getting gone through and rebuilt before 2020 gncc off and a has a 71.95mm piston in it. It has the stock jug with a huge sleeve in it. So it it possible to put a 310 sleeve in a stock cylinder? I would assume that you needed a different jug with bigger water jackets and all that for cooling but I have zero experience with BB in general..
 

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There are a few companies that offered 300/310 resleeves for a stock cylinder. Common issues are head gasket failure, cylinder cracking around the Reed block and coolant leaking past the sleeve (sometimes the coolant passages either crack or they get cut into, then coolant can leak down between the cylinder and the sleeve).
 

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So should I just toss it on the shelf and get another stock cylinder or rebuild it and send it! It wasn't leaking coolant into the oil but whoever rebuilt it the last time used a ton of rtv or silicone so I'm not sure if they were fighting blowing gaskets or if it was just bad mechanical practices
 

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there is no way for coolent to leak into the trans oil from a cylinder.thats the mec seal for the waterpump.i am not a fan of 310 oem cylinders.too thin run hot and most dont know they need a special head gasket and done cut to run them either.
 

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Hey guys this isn't my 1st time posting on here but I have a question I just got this 87 trx250r off of a guy that won it in a raffle so he didn't know nothing about it and then the guy that raffled it didn't know nothing about the motor it. So I ran it at Ironman and quickly realized the jetting was way off. It had a stock 34 pj carb with stock jets in it. I did a quarter of a lap and parked it not really worrying about it because it was getting gone through and rebuilt before 2020 gncc off and a has a 71.95mm piston in it. It has the stock jug with a huge sleeve in it. So it it possible to put a 310 sleeve in a stock cylinder? I would assume that you needed a different jug with bigger water jackets and all that for cooling but I have zero experience with BB in general..
OEM cylinders with 293CC sleeves aka 310's are weak, and prone to leaking easily even when properly setup. IMO Get rid of it, stick to OEM cylinders 66-69.50MM bore with original OEM sleeves; Honda OEM still the most reliable cylinder available, and very fast if properly setup.

Best to go with a 36, 38-39 Carburetor, and a good set of Reeds like VForce3's; jet appropriately.

Carlos
 
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