One piston into two cylinders?

[Zenith]

OK, here is the problem.
The cylinder for my 00 CR125 is off to EG being ported for another two weeks. But I really want to do an Enduro and an MX practice in the next two weeks. My brother has a 98 CR125 that he is not using at the moment but the piston in it has FAR too many hours on it already. So the possibilities are: Put his cylinder with my Wiseco piston(3 hours on it) onto my bike and then when my cylinder comes back put my cylinder back with my original piston OR check the condition of his piston(how do I do this) and put it and his cylinder onto my bike(NOT the option he wants as fears piston break-up and hence wrecked cylinder. So really what I want to know is what is the stroy with putting a used piston into different cylinders? Does break-in actually shape the piston to your particular cylinder or does it just relieve stresses in the piston full stop?

Any input would be greatly appreciated because I really need to start working on it in the next couple of hours!

Thanks very much,
;)

 

[marcusgunby]

Hi Zenith ,
Although not reccommended i have many times swapped pistons about in different cylinders.I have never had a problem with it.If his piston has many hours using it isnt a option.I would put his cylinder on your bike and go for it.When your cylinder comes back fit it, with a new ring on the piston and bed in as per normal with a new cylinder-a few heat cycles under a varying load.

 

[Zenith]

Hi,
Well I ran the 98 cylinder on my bike with my piston with no problems except that I had to swap the exhaust valve actuator arms as well, and I had to use a 98 CR power pipe because the 00 is shorter.
It seemed to make my bike much more top-end but then maybe it was just all the muck that was the need for constant clutching to keep it in the power band...

Zenith,