Milled Head?

[98TEAM ALBA]

I was wondering what is the most you can mill a stock head? Race gas isn't a problem.

[bansheecaptain]

.030 ..if i remember right, thats what mine is milled at and no problems and i'm running high pump gas , 30 thousanths off the head

[mat]

Yep. 0.030" is the generally accept rule.

[98TEAM ALBA]

I have a brand new barrel of vp U-4 race gas that I will be using so I don't car to have it milled enough to need race gas. What is the most that can be milled off? I know you can go .040 because I had another banshee with the head cut .040. But I was wondering if you can go anymore

[bansheecaptain]

I think if you go more then .030 then you might need to put spacers becuase your squash would be to tight.. it's safe to go with .030

[bogart]

I think if you go more then .030 then you might need to put spacers becuase your squash would be to tight.. it's safe to go with .030

301190[/snapback]

what would 30over generally be for copression.

[Ducman]

.030" is about the most you can go and still be safe on the squish clearance, cost about $50 from boonman, and you can still run premium pump fuel. I think cylinder pressure comes out to around 150 psi (sealevel) about like a 21cc dome

 

You can mill a lot more if you have the domes recut, basically just cutting the squish a little deeper so you maintain enough squish clearance to give you at least .035" clearance from the dome to the top of the piston. If you mill enough of the bottom of the head and recut squish the dome will effectively become smaller so compression is high enough that you have to run race fuel. Trinity will do this for about $125.

 

Either way check your squish clearance to make sure it was done right when you reinstall your milled head.

[FlatTrackinIt55]

98 TEAM ALBA i thoght the vp U-4 was for fourstrokes and U-2 was for twostrokes??

[98TEAM ALBA]

98 TEAM ALBA i thoght the vp U-4 was for fourstrokes and U-2 was for twostrokes??

301510[/snapback]

 

 

I am not sure. I picked this up from a friend. I will have to check that out

[bansheeryder21]

How much power will a milled head give you and how much does it cost to do? Is any jetting required or not?

[boonman]

Ryder21, it will cost you less than the $50 mentioned. You will see a nice boost across the board. Throttle response will pick up a bit. Low end response will be better. Normally, if your jetting is correct when you take the head off, it should be on when you put it back on. No changes are needed.

 

To answer the previous question, I have successfully milled a stock head, on my own personal bike .050". I ran a 50%/50% mix of C-12 and 94 octane pump. I NEVER had a problem. In 2 years of running the bike. And I am not "nice" to it all the time. Just be careful. The squish is on the VERY LOW end of "acceptable". Actually, it's "not" acceptable. But, I've done it.