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trx90 cylinder on crf70?

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Will a cylinder from a trx 90 quad fit directly onto a crf70 engine?

Not sure if anyone here has tried making an 88 kit from a TRX 90 as I have not seen one.  Most folks just go with an 88 kit.  I did a quick check on the parts fische and although they look similar but have some differences.  One being different base and head gaskets.  Different not just for the cylinder size, but also for an extra hole on the TRX.  I do know the intake on the TRX is too tall to fit the CRF frame and would require an aftermarket intake with a turnout.  My recommendation is just do it right the first time and get an 88 kit.  Its around $125 bucks from a few places.  I think TBolt sells one and a separate carb kit to enhance the extra CCs.

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Also, the TRX90 cylinder is 69mm tall, 6mm taller than the CRF70 cylinder, requiring longer engine studs, cam chain, and a crank with a longer stroke. The bore size of the TRX is the same as the CRF (47mm).

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Gotcha. I had seen a post about fitting a 90 cylinder on a 50 but not the 70. I looked at the tbolt 88 kit and looks pretty good. I believe that's the route I will go for my boy's 70. I have to put a new piston, rings, and valve seals as the little sucker is smoking and spewing oil out of the exhaust anyway.

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