Planet Minis

OutlawMini · 09-02-2008, 08:14 AM

anyone ever had the head milled to up the compresion my family owns a cnc machine shop and was lokking at trying it.

whighty450rider · 09-02-2008, 12:33 PM

My cr250 has a milled down head. I dont know if you want to try it on a multi 100's of dollar head, but it does increase compression. Only try miniscule amounts though.

Modded · 09-02-2008, 02:08 PM

I've heard of people milling the bottom of the cylinder also.

Paxracing · 09-02-2008, 02:10 PM

Quote:

Originally Posted by OutlawMini

anyone ever had the head milled to up the compresion my family owns a cnc machine shop and was lokking at trying it.

All the time, what motor.

firepower354 · 09-02-2008, 02:42 PM

Not something to rush blindly in to...

rlm996 · 09-02-2008, 08:01 PM

I think you mill the bottom of the cylinder on a 4 stroke and the head on a 2 stroke. It may have something to do with the timing chain clearance. I think........

OutlawMini · 09-03-2008, 05:15 AM

so making the compresion higher that makes more horse power right.

chasetheface123 · 09-03-2008, 05:22 AM

700'sDAD · 09-03-2008, 05:49 AM

Quote:

Originally Posted by firepower354

Not something to rush blindly in to...

No? Isnt more fun that way?

firepower354 · 09-03-2008, 02:58 PM

Quote:

Originally Posted by OutlawMini

so making the compresion higher that makes more horse power right.

-ish...

Paxracing · 09-03-2008, 02:59 PM

Quote:

Originally Posted by outlawmini

so making the compresion higher that makes more horse power right.

what motor.

rlm996 · 09-03-2008, 08:21 PM

I don't know about more power, but def more torque, and higher fuel bills...

firepower354 · 09-03-2008, 08:55 PM

Quote:

Originally Posted by rlm996

I don't know about more power, but def more torque, and higher fuel bills...

Just stop, while you're only this far in the hole...

AFROracing · 09-03-2008, 09:06 PM

on 2 strokes you can mill either the head or the bottom of the cylinder. Doing the head raises compression. Shaving the bottom of the cylinder raises compression and also changes the port timing. You must do a squish test first in order to determine how much to shave in either case. take the spark plug out and get you about 6" piece of solder wire, with the wire in the spark hole kick it over a few times slowly. The piston will squish the solder, measure the solder with a feeler gauge this gives you your squish. It's best to get the measurement on the side of the piston where the pin slides through. On our KX65 stock squish was 45-50 thousands and I took the head down to get it right about 28-30. It raised the compression from 135psi to 155psi.

Again what motor are you wanting to shave each motor will have different squish tolerances.

Kurlon · 09-03-2008, 11:47 PM

Quote:

Originally Posted by AFROracing

take the spark plug out and get you about 6" piece of solder wire, with the wire in the spark hole kick it over a few times slowly. The piston will squish the solder, measure the solder with a feeler gauge this gives you your squish.

Note, if you use solder, you can't go by the direct reading, you have to compare it against a correction/conversion chart. Solder is slightly elastic, so it'll deform, and then bounce back slightly when the pressure is removed. If you go by the direct measurement you'll think there is more clearance than you really have.

OutlawMini · 09-04-2008, 05:28 AM

okay i can do that with no problem this is going to be easy. Im just looking to try it on my stock zongshen 125cc so if it blows then im going to put a GPX 160cc. so lets see what happens. thanks guys.

09-02-2008, 08:14 AM	#1 (permalink)
OutlawMini PM Newbie Join Date: Aug 2008 Location: Burleson Tx Posts: 6	milling head to up compresion anyone ever had the head milled to up the compresion my family owns a cnc machine shop and was lokking at trying it.

09-02-2008, 12:33 PM	#2 (permalink)
whighty450rider 1st Gear Member Join Date: Jun 2008 Location: Michigan Posts: 146	Re: milling head to up compresion My cr250 has a milled down head. I dont know if you want to try it on a multi 100's of dollar head, but it does increase compression. Only try miniscule amounts though.

09-02-2008, 02:08 PM	#3 (permalink)
Modded PM Newbie Join Date: Jul 2008 Location: Musk. Mi Posts: 37	Re: milling head to up compresion I've heard of people milling the bottom of the cylinder also.

09-02-2008, 02:42 PM	#5 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 6,260	Re: milling head to up compresion Not something to rush blindly in to...

09-02-2008, 08:01 PM	#6 (permalink)
rlm996 2nd Gear Member Join Date: Apr 2008 Location: SWL Michigan Posts: 358	Re: milling head to up compresion I think you mill the bottom of the cylinder on a 4 stroke and the head on a 2 stroke. It may have something to do with the timing chain clearance. I think........

09-03-2008, 05:15 AM	#7 (permalink)
OutlawMini PM Newbie Join Date: Aug 2008 Location: Burleson Tx Posts: 6	Re: milling head to up compresion so making the compresion higher that makes more horse power right.

09-03-2008, 05:22 AM	#8 (permalink)
chasetheface123 Chuck Norris for president! Join Date: Nov 2007 Location: Boyne City Michigan Posts: 2,276	Re: milling head to up compresion yup!

09-03-2008, 08:21 PM	#12 (permalink)
rlm996 2nd Gear Member Join Date: Apr 2008 Location: SWL Michigan Posts: 358	Re: milling head to up compresion I don't know about more power, but def more torque, and higher fuel bills...

09-03-2008, 09:06 PM	#14 (permalink)
AFROracing PM Newbie Join Date: Oct 2006 Posts: 62	Re: milling head to up compresion on 2 strokes you can mill either the head or the bottom of the cylinder. Doing the head raises compression. Shaving the bottom of the cylinder raises compression and also changes the port timing. You must do a squish test first in order to determine how much to shave in either case. take the spark plug out and get you about 6" piece of solder wire, with the wire in the spark hole kick it over a few times slowly. The piston will squish the solder, measure the solder with a feeler gauge this gives you your squish. It's best to get the measurement on the side of the piston where the pin slides through. On our KX65 stock squish was 45-50 thousands and I took the head down to get it right about 28-30. It raised the compression from 135psi to 155psi. Again what motor are you wanting to shave each motor will have different squish tolerances.

09-04-2008, 05:28 AM	#16 (permalink)
OutlawMini PM Newbie Join Date: Aug 2008 Location: Burleson Tx Posts: 6	Re: milling head to up compresion okay i can do that with no problem this is going to be easy. Im just looking to try it on my stock zongshen 125cc so if it blows then im going to put a GPX 160cc. so lets see what happens. thanks guys.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)