Custom/Hybrid Shaving cylinders Down. Questions?????

[LIVE2RIDE Powersports]

I'm about to start with my winter build.

I'm going to have my 61x cylinder shaved by a machine shop. I was told most guys have the top shaved, but if i was to shave the bottom 50 thousands wouldn't it produce more bottom snap since its lowering the ports?
My friends OP 650sx cylinder came 50 thousands less off the bottom.
Do i have to pop the sleeves out? I'm guessing yes.

 

[WFO Speedracer]

Yes you must pop the sleeves out to do this

 

[#ZERO]

Shave your head and leave the cylinder alone.

The stock 61X cylinder has pretty good port timing suited for the SJ freestyle setups. Spend your money elsewhere like on some porting and make it worth while.

If you mill the top of your cylinder squish band will change and the exhaust duration and blowdown time will increase. If you shave the bottom you'll have to remove the sleeves and the exhaust duration is already at 180 degrees and you won't gain anymore performance.

 

[Waternut]

You can see the top edge of the piston through the current exhaust port anyway. I'm certainly no engine builder but I can't imagine lowering it anymore would do very much for bottom end power. I've heard of people running cylinders (can't remember which) without a base gasket though.

 

[LIVE2RIDE Powersports]

Shave your head and leave the cylinder alone.

The stock 61X cylinder has pretty good port timing suited for the SJ freestyle setups. Spend your money elsewhere like on some porting and make it worth while.

If you mill the top of your cylinder squish band will change and the exhaust duration and blowdown time will increase. If you shave the bottom you'll have to remove the sleeves and the exhaust duration is already at 180 degrees and you won't gain anymore performance.

Thanks. That was what i was looking for. My friend ports mine for free and really makes it rip.

I'm think of running a Ported big bore, ada head, TL, b-pipe, etc.

I didn't know if we lowered the port it would increase the snap any.