okbeast Posted March 14, 2007 Report Share Posted March 14, 2007 Just a short background, with the stock head I was making around 105 PSI in each cylinder. I got ahold of a head that is milled .040 and with that on I have 125 PSI in each side. Now I know that is low and that I should rebuild it but since (1)each side is even (2) I'm going on a riding trip next week and don't have time for a rebuild and (3) I'm a poor college student I can't do a rebuild just yet. I'm looking to get a coolhead with some 20cc domes b/c I'm looking to get my compression somewhere around 145-150 so this should do it. As mentioned, poor college student looking for some more compression right now...would it be ok to mill say another .020 off the head just for now? No it won't stay like that for long, yes I'm planning on a rebuild once I get my 1st paycheck, this is just one of those "quick fixes" that I don't see really causing any harm. I just want to know if mechanically it can be done w/o any problems. Also what's the max that can be taken off the stock head? Thanks! Quote Link to comment Share on other sites More sharing options...
oneslowbanshee Posted March 14, 2007 Report Share Posted March 14, 2007 I am not sure the max you can mill a stock head but I have a head on my stock bike that is milled .60ths but it has also been redomed I have about 145psi on each cyl unported virgin but if I am not mistakin I think anything over .40 has to be redomed I like the stock cut head it kinda looks like a sleeper untell u know what to look for on a cut head hope this helps also I am about 900 feet above sea level Just a short background, with the stock head I was making around 105 PSI in each cylinder. I got ahold of a head that is milled .040 and with that on I have 125 PSI in each side. Now I know that is low and that I should rebuild it but since (1)each side is even (2) I'm going on a riding trip next week and don't have time for a rebuild and (3) I'm a poor college student I can't do a rebuild just yet. I'm looking to get a coolhead with some 20cc domes b/c I'm looking to get my compression somewhere around 145-150 so this should do it. As mentioned, poor college student looking for some more compression right now...would it be ok to mill say another .020 off the head just for now? No it won't stay like that for long, yes I'm planning on a rebuild once I get my 1st paycheck, this is just one of those "quick fixes" that I don't see really causing any harm. I just want to know if mechanically it can be done w/o any problems. Also what's the max that can be taken off the stock head? Thanks! Quote Link to comment Share on other sites More sharing options...
okbeast Posted March 14, 2007 Author Report Share Posted March 14, 2007 Wth is redoming? Quote Link to comment Share on other sites More sharing options...
2003LimitedBanshee Posted March 14, 2007 Report Share Posted March 14, 2007 Wth is redoming? Redoming compensates for the fact that you virtually eliminate (if not totally) you squish band in the dome of the stock head by milling to that extent. Redoming, is just like it sounds, the head essentially has the domes recut to restore the squish band. Quote Link to comment Share on other sites More sharing options...
okbeast Posted March 14, 2007 Author Report Share Posted March 14, 2007 I thought that's what it was, but I didn't think anyone ever re-cut the stock head. Who did it for you? Quote Link to comment Share on other sites More sharing options...
blowit Posted March 14, 2007 Report Share Posted March 14, 2007 I thought that's what it was, but I didn't think anyone ever re-cut the stock head. Who did it for you? You might take a look here. www.mullengineering.com Not to plug too much for our heads but we have done a lot of research in what works and we can get as high as 210psi static compression out of a stocker with stock porting at sea level. Your numbers do sound a bit low so I am wondering what gauge you are using. You could have a lazy top end. Quote Link to comment Share on other sites More sharing options...
okbeast Posted March 14, 2007 Author Report Share Posted March 14, 2007 (edited) It's a good Craftsman gauge so I know it's not that. I know the top-end is nearing time for a rebuild, but like said I don't have the money/time for it right now, or enough $ to pick up a coolhead so I'm looking for a cheaper route and am just wondering if this is mechanically sound. Looks like ya'll have some good stuff there blowit, but for that much $ I could pay another 30 bux and get a coolhead...I'm looking for cheaper but still reliable right now. Edited March 14, 2007 by okbeast Quote Link to comment Share on other sites More sharing options...
blowit Posted March 14, 2007 Report Share Posted March 14, 2007 It's a good Craftsman gauge so I know it's not that. I know the top-end is nearing time for a rebuild, but like said I don't have the money/time for it right now, or enough $ to pick up a coolhead so I'm looking for a cheaper route and am just wondering if this is mechanically sound. Looks like ya'll have some good stuff there blowit, but for that much $ I could pay another 30 bux and get a coolhead...I'm looking for cheaper but still reliable right now. Our pricing is a bargain compared to what you get in the industry. Most shops will just plane or deck the head leaving a key area dangerously thin. In terms of reliability, you just don't get any more reliable than the stock setup with the steel gasket. O-rings just don't hold a candle to a good copper or steel gasket. By trying to get more pop out of a lazy engine, you might be working to end it's life even sooner! Trust me, if it is so lazy that comp is falling off, the next thing to happen is a broken piston skirt so there goes 4-6 bills in a new crank and mybe some new cylinders. However, we call this "justification for modification". The best advice I could give is don't ride it unit you either take it apart and mic it or fix it right. JMO. Quote Link to comment Share on other sites More sharing options...
okbeast Posted March 14, 2007 Author Report Share Posted March 14, 2007 Yeah, I figured this thread would end up with me hearing that and I agree...eh about 50%ish lol. Guess I'll leave it how it is and see how it does. Quote Link to comment Share on other sites More sharing options...
2003LimitedBanshee Posted March 14, 2007 Report Share Posted March 14, 2007 Our pricing is a bargain compared to what you get in the industry. Most shops will just plane or deck the head leaving a key area dangerously thin. In terms of reliability, you just don't get any more reliable than the stock setup with the steel gasket. O-rings just don't hold a candle to a good copper or steel gasket. WOW! I agree with you on the bargain and your products do look very nice, but I can't agree with your last statement. At lower cylinder pressures you might have a point, although I've yet to see an o-ring in good condition leak. Now, if you had said that o-rings don't hold a candle becuase it is easier to improperly install an o-ring and cause a leak, I would have agreed with that also. But, the simply fact in my experience is that under much higher cylinder pressures o-rings are still the standard. True, copper or steel gaskets have quite a long way and are capable of handling much higher pressures than they once were, but to the best of my knowledge (conceeding that you seem to have quite a good knowledge base) o-rings are still the winner in high compression scenarios. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted March 14, 2007 Report Share Posted March 14, 2007 OK... I didn't read this whole post, kinda skimmed it...so, if this was said, I apologize for repeating. Don't mill your head to raise compression for a quick fix. Bad idea. You know the engine is already worn, by putting more compression on already weak/worn pistons and rings, you're asking for more failure. I personally wouldn't go more than .030. Are you prepared to weld the crank too...with more compression? Just lookin out bro. Quote Link to comment Share on other sites More sharing options...
okbeast Posted March 14, 2007 Author Report Share Posted March 14, 2007 Ya I plan on getting the crank trued/welded with new bearings this summer when everything is torn apart for my idea of a complete rebuild :biggrin: I plan on getting it ported but sure as hell don't wanna do it over the summer and not have a bike to ride, so it'll probably just be a rebuild at the beginning of the summer when I get some $ flow and then when it starts to get cold send it up to Jeff. Quote Link to comment Share on other sites More sharing options...
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