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myson

M80 Crank

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Hi, I have just split the cranks on my M80 engine and have found it has 3 main bearings. I was sure that it was only later models that had this feature. I also want to remove the two gearbox bearings that are located in blind holes, what is the best/easiest method?

Cheers,

Myson

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I suspect that someone has upgraded the bearing to the later spec. This can be done to all engines as far as I know.

The easiest way I know of getting the gearbox bearings out is to use a pair of mole grips on the outside race and then gently heat the area

and just pull and turn at the same time. should just pop out. just done one myself. Hope this helps

Edited by noel063

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I suspect that someone has upgraded the bearing to the later spec. This can be done to all engines as far as I know.

The easiest way I know of getting the gearbox bearings out is to use a pair of mole grips on the outside race and then gently heat the area

and just pull and turn at the same time. should just pop out. just done one myself. Hope this helps

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Hi, thanks for the reply, I believe tht you can use a modified seal retainer to do this but this one has the bearings located inside the original casting, Dont know if this is possible on original M80 case.

Myson

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My M80 has 3 main bearing which according the the manual is standard for the year.

Simplest way to remove all bearings in to put each crankcase in the oven @

145 degrees for 15 minutes and they will simply drop out.

Reassembly is just the reverse, but put the bearings in the fridge prior to dropping into the heated crankcase.

Oh dont for get to put the crank oil seal holders (without seals) in place the stop the bearings droping right through.

Finally put a pepperoni pizza in the oven to get rid of the oil smell. It just keeps the wife happy!

Have fun

Martin

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I stand corrected on the mains question Triple-X. So now I have to ask wether it is worth upgrading to three on my model 183 engine before I rebuild it?

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Hi

I have no info on your engine but would have thought if space allows, then 3 bearings are better than two.

Talk to Bultaco uk they will have a much better idea.

All the Sherpa info they provided was spot on.

Regards

Martin

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Great post re removing bearings Martin, wife wouldnt notice smell the way she cooks!!. Will still have the pizza though,

Myson

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Have a look on AMAZON for the Clymers manual.

I just boought a new manual Dirt Bike Collection: Bultaco, Ossa, Montesa Workshop Manual (Clymer Collection Series) for

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