High compression build? - Page 2

**845mx5** · 01-03-2010, 12:16 PM

also i found someone to mill my head. What is a safe amount to mill off the head that can be used with a flattop piston?

Phantom · 01-03-2010, 03:03 PM

Quote:

Originally Posted by 845mx5

that didnt really help. i guess i was unclear. What do the numbers alongside the flattop pistons represtent? a different bore? or is it taller, meaning it would up te compression?

You mean the numbers stamped in the piston? If those are what you mean then they indicate if the piston is std, overbore .010, .020, etc

Phantom · 01-03-2010, 03:05 PM

Quote:

Originally Posted by 845mx5

also i found someone to mill my head. What is a safe amount to mill off the head that can be used with a flattop piston?

.050 with stock cam.

**minidragbike** · 01-05-2010, 07:16 PM

Running to much compression with a stock head, your gonna end up loosing more power than your gaining. Especially with a stock cam.

Phantom · 01-05-2010, 07:27 PM

^^ Very True.

**845mx5** · 01-05-2010, 08:17 PM

What would cause me to lose power? If i milled .050 off of the head, flattop piston and stock cam, where would i loose power? Would i need to open up the valves? I plan on getting a better cam but that will be some time from now. I have a couple hundred id like to spend and get the best bang for my buck. What would you suggest? Milling the head will be free.

Phantom · 01-05-2010, 09:12 PM

Quote:

Originally Posted by 845mx5

What would cause me to lose power? If i milled .050 off of the head, flattop piston and stock cam, where would i loose power? Would i need to open up the valves? I plan on getting a better cam but that will be some time from now. I have a couple hundred id like to spend and get the best bang for my buck. What would you suggest? Milling the head will be free.

Ok since you are gettin a cam, here is a common recipe 265 cam, 1.2 rockers, milled head, 22mm mikuni, flattop piston, billet rod and other odds and ends and you should be good to go, give it a good gearing and hold on. Oh and what causes you to lose power with stock cam may MDB correct if i'm wrong but its duration.

**minidragbike** · 01-05-2010, 09:17 PM

The factory carb already is restricting the stock head flow. Adding more cylinder pressure just makes the flow even harder to get in there.