72mm cylinder kit

[jimwildman]

do you suppose this would bolt on to a cg250 engine? I found a cheap watercooled head to match it.. could run an electric pump, e.t.c.

https://www.aliexpress.com/item/YX-C...770210880.html

or

https://www.aliexpress.com/item/Moto...851697490.html

there is a 70mm version as well

[jimwildman]

oh, wow i see it has an 81mm stroke... so even if it bolted up..


Nevermind

[jimwildman]

Originally Posted by jimwildman

oh, wow i see it has an 81mm stroke... so even if it bolted up..


Nevermind

the stock cylinder deck height is 80mm, this one shows 81mm. so close...

[Megadan]

The real things to consider would be the cylinder bolt hole spacing and the outer diameter of the cylinder where it goes into the base. Likely that section is larger in diameter and would require machining just to get the cylinder to fit. Then this is assuming the bolt spacing is the same, which is highly unlikely.

Also, that piston is designed for an 18mm wrist pin, which is larger than the 15-16mm pins used on the CG250 air cooled engines.

You would find it much easier, and probably cheaper, to simply swap in the whole "300 cc" engine.

[jimwildman]

Yep, not right now though, the cheap price for the cg300 is still expensive..

Ill wait to see how yours works with the decked head...

[Megadan]

Originally Posted by jimwildman

Yep, not right now though, the cheap price for the cg300 is still expensive..

Ill wait to see how yours works with the decked head...

Why wait? JerryHawk250 has a ported and decked head on his bike and reported an improvement in the top end of the powerband with no loss to the low end.

[2LZ]

Originally Posted by jimwildman

the stock cylinder deck height is 80mm, this one shows 81mm. so close...

Build up a 1mm bed of JB Weld on the top of the cases? ;-)