SX/SXi/SXi Pro Milled head...

[sxipro02]

I'm wanting to mill the head on my ski soon, I'm wondering if anyone knows how much i need to mill off to get around 180psi. I have about 160psi now on mine, all stock motor with pipe and prok filters. I tried to search for specs but had no luck.

 

[JetPilot1970]

On my personnal experience, you'll find 2 psi on each 0.001" so if you want 20psi, go for 0.010".... This is what I done to my ski, 180psi is the results

 

[sxipro02]

thanks, That is what I was looking for, I know there is much more involved ways of measuring and what not but I just want to get a little more out of my stock head. If I decide to build the motor with port work, bore, ect. then I'll worry about it or just buy a aftermarket head.

 

[fastony]

Cut your head .030 and then recut your squish band at 4 degrees angle and leave a .010 lip on your squish band and that should give you 20lbs. more compression. Also check around for a thin head gasket there use to be a .005 head gasket you could get from Watcons or you can get the .005 base gaskets from TBM and that would lower your port timing for lowend and give you more compression too.

 

[gorilla]

i got a old school oem 750 kawasaki race head that uses the o-ring + metal head gasket setup.
it was made by westcoast and has about 185-195 lbs of compression on a stock 750 cly.
let me know if you need pic's of it.

gorilla

 

[Hirschfelt]

Cut your head .030 and then recut your squish band at 4 degrees angle and leave a .010 lip on your squish band and that should give you 20lbs. more compression. Also check around for a thin head gasket there use to be a .005 head gasket you could get from Watcons or you can get the .005 base gaskets from TBM and that would lower your port timing for lowend and give you more compression too.

Just milling your head leaves you open for detonation. You must adjust the squish band as stated above. Some people get away with out doing it and others dentonate. The cost is a minimal diffrence between just milling it and getting the squish set for the octane you want to run.

 

[sxipro02]

Thanks guys, I hear there is a shop not too far from St.louis where i live that will do the head right and also does good port work. I'll just wait till its too cold to ride and get the cylinder done at the same time.

 

[sxipro02]

I called John from Z Force, I'm going to have him mill my head and bore my exit nozzle. I didn't really get a clear answer from him on doing port work, I got the price for it but wasn't clear on if its something I should do at this time. I would like a little more power but want to keep it reliable and running on 93 octane. I currently have 165psi comp so going through the motor probably isnt needed right now.
My question is, is it worth the money to get some mild port work done or should I just skip on that? looking at about 400-500 for him to go through it and replace pistons, rings, bearings, ect. and do the porting/cleaning.

 

[509freerider]

In my opinion porting is well worth the money, I would do it on every motor I build. Plus with that pipe you have you will be very happy you did.

 

[nickelggg]

might a stupid question but what is a sqish band???

 

[JetPilot1970]

The lip around the dome in the head

 

[sxipro02]

man, this thread got pulled from down low lol

 

[sxi steve]

FYI- I had GroupK mill my head, I think I payed $80. My ski was up to almost 180psi. I run 93 sunoco gas. All is well.

http://www.groupk.com/

Peruse their website, got some good reading/info. I've talked to, and used them, seem pretty good.

 

[sxi steve]

No stupid questions here.