kenr74 Posted January 19, 2004 Report Share Posted January 19, 2004 I just got done rebuilding my bike and it is so much better than before. I had to do a new crank and top end so while it was apart I lighted the flywheel and shaved .060 off the head. I'm getting 163# and 165# now in the cylinders. Does that sound about right? Quote Link to comment Share on other sites More sharing options...
IRONDUKE Posted January 19, 2004 Report Share Posted January 19, 2004 WOW I shaved mine .035 , I was told that was the max. Although compression is a good thing Quote Link to comment Share on other sites More sharing options...
PassionRE Posted January 19, 2004 Report Share Posted January 19, 2004 Compression is a good thing, but not at the cost of proper squish clearance. You best check your squish clearance and hope for at least .028" You cant just go and cut what feels good with the variety of pistons, base ,and head gaskets that are available out there and expect a reliable engine without doing the the dirty work..IMO... Oh, and as far as "how much is too much?"..LMAO...depends on who you ask......Jim Quote Link to comment Share on other sites More sharing options...
kenr74 Posted January 20, 2004 Author Report Share Posted January 20, 2004 Well, I have heard everybody on hear saying not to shave it more than .035 but most shops in the area are doing them at .060. I ran it for about four hours before I had an electrical problem and it feels great. Quote Link to comment Share on other sites More sharing options...
Ducman Posted January 21, 2004 Report Share Posted January 21, 2004 Some shops like Trinity recut the squish band so it maintains the correct squish clearance. Do you know if they recut yours or not? Quote Link to comment Share on other sites More sharing options...
kenr74 Posted January 21, 2004 Author Report Share Posted January 21, 2004 We talked about the squish band but I don't even know what it is. What is it anyway? Quote Link to comment Share on other sites More sharing options...
Ducman Posted January 21, 2004 Report Share Posted January 21, 2004 This link describes its function and has a good pic of a head but doesn't actually point it out real well. http://trinityracing.com/products/yamaha/b...eeheadmods.html The squish band is the flater angled area around the perimeter of the combustion chamber, the area surrounding the deeper domed part. In this particular pic it is the area that has the groves cut into it (Trinity's "turbo" head mod). Quote Link to comment Share on other sites More sharing options...
boonman Posted January 21, 2004 Report Share Posted January 21, 2004 Your squish right now if the dome was not re-chambered is phucked. if you are not running high octane to combat the detonation, you will surely grenade your brand new top end. Luck will not be in your court. Grab some solder, and check your squich. IMMEDIATELY. Right now, that thing may be a time bomb. Or, it may not be. It depends on who did the work. if you just took it to a machine shop, and told the mto whack the head down, they didn't do the domes. My bike currently runs 175-180# on my guage. I run a mix of race fuel and pump fuel. It diesn't ping, and it will stay that way.... Quote Link to comment Share on other sites More sharing options...
fixitrod Posted January 21, 2004 Report Share Posted January 21, 2004 Compression is one way to determine pre-igniton along with squish. You need to keep in mind compression ratios, dome angles on the heads , porting, and many factors. Some builders can make a motor run 180psi and never detonate on 93 pump gas. Other don't want too. There are a lot of factors to consider. Some play it safe and mix 50/50 race and gas 160 and over. But your squish is very important. That is the area that keeps the crown of the piston cool. If it's to tight, it gets to hot. YOu don't want that. It will melt down. Remember, fuel cools, oil lubes. Quote Link to comment Share on other sites More sharing options...
Dextreme Posted January 22, 2004 Report Share Posted January 22, 2004 Kenr, who is cutting your head? I am having Chad cut mine to .065, but he is reworking the squish and o-ringing it. Quote Link to comment Share on other sites More sharing options...
kenr74 Posted January 22, 2004 Author Report Share Posted January 22, 2004 MP did it so I'm not worried about it they did it right. I was just a little suprised how high the compression was. It was running great Saturday at SL until I hit some water and then it wouldn't fire after that. I haven't messed with it much yet but I think my CDI or coil may have bit the dust. Quote Link to comment Share on other sites More sharing options...
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