Milled VS coolhead

[James-26]

I was going to buy a coolhead for my banshee with 20 or 21cc domes but was told a milled head is just as good at half the price of a coolhead. IMy elevation is around 890 feet. My banshee has a stock head now with 66.5 wiseco pistons. I checked my compression and I'm right at 100 psi on each cylinder. From what I read that is normal compression for my elevation and stock head. I'd like to see 115 to 125 psi on each cylinder as I feel that will give me a nice increase down low. Will a milled head be able to put out the numbers I'm looking for or will I need to go with a coolhead? Again I'm new to 2strokes and really have no idea what I'm talking about.

[papa_smurf49319]

Theres nothing wrong with a milled head, it is a good idea to get it rechambered to keep the squish band within spec. A cool head is nice because of the dome interchangibility, you can swap domes so you dont have to run race gas all the time if you dont wish to. I have a milled and rechambered head on my 4 mill that i like alot, its cut for race gas and im at about 185psi cold on each cylinder. I would like to get a cool head (noss head) for the bling factor and the interchangeable domes.

 

 

 

Cody

[TwistedSheeRida]

Hate to break it to ya but 100psi is unexceptable in my book. As long as there within 5-10 psi of each other you can get another season out of them but you should start saving up some money for a top end. Your going to have to resleeve it or buy new cylinders so i would def start saving. A milled head is a cheap way of bumping up your compression, but the good thing about a cool head is you can interchange your dome ccs.

[James-26]

Hate to break it to ya but 100psi is unexceptable in my book. As long as there within 5-10 psi of each other you can get another season out of them but you should start saving up some money for a top end. Your going to have to resleeve it or buy new cylinders so i would def start saving. A milled head is a cheap way of bumping up your compression, but the good thing about a cool head is you can interchange your dome ccs.

 

Who says I need to save? maybe I have the money sitting in the bank. Anyway my engine was just rebuilt 30 hours ago and from what I read the other day 100psi is fine for my elevation. Wish I could remember where I seen this info. Oh and just because I'm .100 overbore dont mean I can't just hone/deglaze and install new rings as I'm sure my cylinders are still in good shape.

[papa_smurf49319]

im at 852 ft and a brand new top end is at 125 or 130psi

[James-26]

im at 852 ft and a brand new top end is at 125 or 130psi

 

 

Interesting..... well then maybe I do need new rings and a hone.

[mike87]

yeah 100 psi is pretty low i have a 95 shee and it read 120 psi in each cylinder after 14 years on the stock pistons before i rebuilt it, im at the same elevation as you to, a cool head is definately the way to go, i love my noss head.

[blowit]

It would be a good idea to share specs about your comp gauge or even post a pic of it. I am confident there are plenty of top ends replaced solely on comp numbers that may or may not be accurate.

 

 

http://mullengineering.com/rt/files/2_tech_docs/THE%20TRUTH%20ABOUT%20COMPRESSION%20TESTING.pdf

 

I did a quick write up a while back on a few of the questions on comp gauges.

 

 

 

Mull Engineering

[James-26]

Hmm well then let me ask this. If you went 14 years and was only at 120psi when you rebuilt and I'm at 30 hours and already at 100psi maybe I'm just not checking the compression the correct way. My shee runs like a top and fires right up after 1-3 kicks. I would think if compression was low it would be a bitch to start. So what is the correct way on checking the compression. I have a motorcycle compression tester that I use.

[papa_smurf49319]

compared my gauge to another and the compression was the same on both! This was a expensive sears gauge at one time. Never let me down, not a cheap autozone harbor freight special, i would like to get a snap on though.

[SNTBANSHEE]

http://mullengineering.com/rt/files/2_tech_docs/THE%20TRUTH%20ABOUT%20COMPRESSION%20TESTING.pdf

[9498banshee]

when you cut a head you usually gain about 20 - 25 psi on .030" i have a coolhead and love it but it was on there when it got it, i have cut a few heads and as far as performance bout the same to me. but the coolheads do look alot better.

[tundish2800]

when you do your compression test kick each side 30 times and see what you get thats what i do and its pretty accurate.

[mike87]

you might or might not have a bad compression tester, ask one of your friends or someone that has one and you can see if it is accurate or way off to what yours shows

[James-26]

Here is the tester I use. I got it off ebay about a year ago. Can't remember what I paid for it.