Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[ImBroke]

Is it possible to stick with the stock pistons and mill the heads enough with the use of a .030 head gasket to reach 10.5:1 comp ratio?  Any issue with piston to valve clearance with a .585 or less cam?  Knowing each head is slightly different, how much would have to be milled off to reach 10.5:1 ?

[prodrag1320]

Is it possible to stick with the stock pistons and mill the heads enough with the use of a .030 head gasket to reach 10.5:1 comp ratio?  Any issue with piston to valve clearance with a .585 or less cam?  Knowing each head is slightly different, how much would have to be milled off to reach 10.5:1 ?

what CID motor are we talking about?

[ImBroke]

2013 CVO 110 stock

[TorqueInc]

  You can

Better bet is doing it with pistons

[ltank]

If you mill the heads, you would be basically stuck with that C/R . To go back means buying another set of heads. If you use stock pistons would they be strong enough with the extra load at high rpm?

[HILLSIDECYCLE.COM]

Piston strength is a non-issue, and re-surfacing the head is a very economical/accurate way to establish the compression needs of a given build.
How much to remove??
CC them first, then cut, cc, cut, cc until you hit your target number.
Scott

[kojack]

I concur with the others that say do it with pistons.  I have a head milling maching,  however,  Its for correcting other issues not just for increasing c/r.  You can't go back.

[GMR-PERFORMANCE]

We will machine the deck to alter compression in small amounts. However it is better to use a piston to obtain the comp ratio if you are looking for that type of increase. You piston to valve , intake fitment, exhaust fitment , push rod angularity , FBW motor to cylinder fitment , etc all work better if you don't machine a larger amount of the deck.

Below is a set of 110 heads ,...that where sent to us for repair. These have have been decked more than we like to see. Every shop will do things a certain way.  Not to mention adding the piston + bore and hone will also correct the less than stellar piston to wall fitment from the factory.  Your bike up to you. But a picture they say is worth a 1000 words, this customer had mainly four letter words . 

[Twism_23]

Steve, just curious. What do you consider a small amount, .030 or less than that? Thx

[smiley1049]

I think I seen a set like that any carbon on pistons it wood knock !

[TorqueInc]

We will machine the deck to alter compression in small amounts. However it is better to use a piston to obtain the comp ratio if you are looking for that type of increase. You piston to valve , intake fitment, exhaust fitment , push rod angularity , FBW motor to cylinder fitment , etc all work better if you don't machine a larger amount of the deck.

Below is a set of 110 heads ,...that where sent to us for repair. These have have been decked more than we like to see. Every shop will do things a certain way.  Not to mention adding the piston + bore and hone will also correct the less than stellar piston to wall fitment from the factory.  Your bike up to you. But a picture they say is worth a 1000 words, this customer had mainly four letter words . 

   Looks like that one was butchered pretty good

  Also appears that the gasket was digging in a little harder on the right than the left....pretty good indication it was not square when decked.

[prodrag1320]

if you mill it to the 10.5-1 point,you will DEFANATLY have valve/piston contact (even with cams with a lot less TDC than the 585),i agree with steve,get the compression with pistons