HI!

 

I have a Rev3 125 2008 that soon need a new piston.

 

How does the system with A,B or C pistons work? Which to buy?

 

Reg/Martin

I had a B in mine and lampkins said to go to D, so depends what's in yours now.

In my experience putting a new piston into a worn cylinder never pays. Its usually noisy again in a matter of weeks. Get a new piston and get Langcourt to re coat the cylinder to the new piston. Its an extra £120 but its a much better end result

In my experience putting a new piston into a worn cylinder never pays. Its usually noisy again in a matter of weeks. Get a new piston and get Langcourt to re coat the cylinder to the new piston. Its an extra £120 but its a much better end result

This is quite true, as the pistons are only .01mm different, any wear in the cylinder will still be there. If youy are trying to fix a rattle, start over with a matched set!

Edited March 3, 201610 yr by copemech

As said above barrels do not ware evenly I had a B31 std size The ware was 15thou Had to bore it to + 40 and there is still a mark on the top front of the bore The crank turns forcing the piston onto one face of the barrel so they tend to ware oval measuring the side to side top and bottom them measure back and front and the sizes can be very different Had cub barrel done 3THO difference top to bottom f/r and same size side to side

I think the B31 will wear slightly differently to a beta. Fyi Westwood liners do a good BSA liner.

I am in a similar situation.

 I took the barrel off my Rev3 to inspect the piston and bore, and also after a rattly engine.

Had initially thought i would just put some new rings in and job done, but after sending my barrel to Longcourts for measurement, it is confirmed that the barrel is worn, alot...

So with the advice of Langcourts the barrel is being replated to original size with a new piston to match..

Expensive, but worth doing right.

Even my Moto Guzzi V50 did not wear evenly and it is a coated liner and you can see where the rings run also where the piston are pushed against the bores Granted the mileage was a lot higher