CB 175 Engine Parts

Foxriderar77

New Member
I found a bunch of cool looking engine parts from Powroll Products. They are all listed as cb125 stuff. My question is, will they be compatible with my cb175? I am doing a rebuild this winter and would like to add new high compression pistons and re do the valving with new springs and such. Is there a better way to do this?

Thanks,

Andrew
 
To the best of my knowledge, nothing major is compatible between the two motors.
 
It is possible to take a pair of Powroll CB125 pistons and then machine the crowns to make them work in a 157 but that's a hard way to go.

Mike Riddle has oversized pistons available with a crown shape that's the same as stock. IIRC they come in 55 and 57mm sizes.
 
Riddle's pistons with larger bore and stock crown would be higher compression as well as larger capacity.

One problem is that they have an old school Hemi head designed for the CB125 41mm bore and the heads didn't change much from then through 160 to 175 to 200cc. Same tight -tall little combustion chamber that's no good for serious revs or power. What you really need is to lower the head and machine some off the block and use pistons with a different squish band arrangement.
 
That's the easy way.... We had one were we welded up part of the head and machined a completely different squish band and combustion chamber shape. Once you start down this slippery slope, there's no going back. You get hooked on doing things in better ways trying to make engines do things they were never designed to do.
 
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