Hello, I'm fitting a 2mm stroker crank to my RCMK evo motor and want to know the minimum squish clearance, I'm looking to raise the compression as I run mine on methanol. Cheers

tight bearings and good crank ... Combustion chamber lapped into exact shape of pistons dome .... Take it down to @ .008"-.010"

Thank you, how would I go about lapping the combustion chamber ?

Take piston and place it dome side down on the back side of some 180 grit wet/dry sand paper, trace it's diameter with a pen, now cut out the circle slightly smaller than draw so it is AS CLOSE to actual bore diameter as possible.
Cut the circle into 3 wedge parts removing a bit of paper ( @ 1/8" ) along each cut and remove the pointed end at center.
Now with some contact cement glue the 3 wedges of paper on top of pistons dome evenly spacing them out so paper lays flat and out to edge by ring.

Get a square stick that fits between pin boss's so you can twist piston back and forth.

Now go into a bucket of water / under the running water of a sink etc .... wet up the cylinder and piston drop it into cylinder and start twisting piston round and round frequently pulling piston out and washing away debris. When happy with clean up and/or clearance you want your DONE.


Regards,
Scott

Just an update on how things are going, In the end I had to fit a 1mm stroker crank from rcmk no one seems to make a 2mm crank for the evo motor.

Any way I have lapped the squish band and reduced the clearance to 0.010", I left the piston as standard and fitted a tunned pipe and started with a length of 12" The other thing I have done is to run her on petrol instead of methanol.

Been out today on the water and very pleased with how it's going.

One thing I would like to know at this stage is, would running the ignition timing in the advanced position on the RCMK evo be an advantage ?

Advancing can help find more torque tho generally at the expense of RPM
Pretty safe in saying most keep coil in the stock position.

Hello, I'm fitting a 1mm stroker crank to my 26cc zenoah and want to know the minimum squish clearance.

JMO ... would aim for @ .018-.020" and go no tighter than .015"