raising compression/skimming the head

adg · Post by **adg** » Sun May 04, 2003 9:27 am

Anyone know how much I can skim the head and top of the block in order to get the last few HP ?? I dont want to take it too far so that Id need to run on AvGas, but there must be some reasonable amount like 20 thou' that can be safely removed ? Im pretty certain that such a small amount wont really affect the piston/valve clearance. ade

exupturbo · Post by **exupturbo** » Sun May 04, 2003 3:38 pm

Buy the Wiesco 1040 kit if you would like a higher CR, on mine it gave close to 13:1. If you skim the head/block then there is a very real risk of valve to piston contact<img src=http://www.ezboard.com/images/emoticons/frown.gif ALT=":("> I had a set of big end bearings fail and there were witness marks on the pistons from where the valves had touched, no damage done but it does prove that there is not much room for skimming. Mark

adg · Post by **adg** » Sun May 04, 2003 6:40 pm

I didnt realise the piston valve clearance was so tight! thanks for the help. ade

yzf 1 · Post by **yzf 1** » Thu Jun 05, 2003 6:01 pm

My '97 t/ace has had the top of the barrels planned enough to give us approx 14/15:1 comp ratio. It has a very mild port job, altered cam timing, aftermarket 4-1, flat slides & runs on methanol - hence the high comp-ratio. The bike runs well & for the last 3 yrs have had no trouble - hope this helps.

adg · Post by **adg** » Fri Jun 06, 2003 9:35 am

yzf 1: how much did you have removed?

yzf 1 · Post by **yzf 1** » Sun Jun 08, 2003 2:45 am

We ended up taking off around 0.5mm Keep in mind that this engine will not perform on pump gas or aviation fuel without some octane boost type products

flyingcircus68 · Post by **flyingcircus68** » Sun Jun 08, 2003 6:42 am

Methanol? Do you race? I can't imagine you can go to far on the road without someone trailing behind you carrying gas cans full of methenol. The energy density is so much lower, so fuel is consumed quickly. Have you ever dynoed it? I would imagine that it runs furiously with output in the high 100s.

yzf 1 · Post by **yzf 1** » Mon Jun 09, 2003 3:44 am

Yes, No, Yes, No, & YES Its the off-season here, so time to go make some power! Safe riding C.U. <img src=http://www.ezboard.com/images/emoticons/devil.gif ALT=":evil">

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