300/440/550 Getting head milled need advice

[Words]

Getting my 550 head milled race shop by me is giving me a great price $25. Only problem he asked how much I want taken off but I haven't found anything on here. How much should I have him remove. Don't want to run race gas but premium is fine. Thanks

 

[flgliderpilot]

You should see what the squish measurement is currently before considering this. You could also find a thinner gasket to increase compression without the mill work, and it's reversible if you don't like it. You can measure squish by inserting a piece of solder which is .01 over the stock (expected squish) into the spark plug hole, and letting the piston smack it a few times ... then measure the actual thickness. Good description is here:

http://www.swedetechracing.com/news...p/how-to-check-squish-on-a-two-stroke-engine/

 

[spookyjjj]

I used a oem gasket and got my head milled and my comp was 170 and it costs 70.00. My machinest never asked me how much I wanted off but do you wanna run pump gas or race gas lol

 

[Words]

Pump gas which I was told I'd be good up to 180psi on pump. I'd like to be around 170-180 psi

 

[kwakhead]

if youre running premium pump gas, 93 octane, yes itll work for 180psi. after that, if you dont want to run straight up race fuel, you can use octane booster. a little bit cheaper. if youve got a stock head, for a 550, id take 2 mm off it, your squish will be gone, but thats the only way ur gonna get some real performane out of those huge stock domes.