98_shee Posted May 21, 2008 Report Posted May 21, 2008 (edited) I have a 4 mill long rod with cut dome's and proted cylinders for a stock stroke crank, one of my buddy's gave me some uncut dome's, could i get more power if i switched to the uncut dome's and ran a spacer plate? Thanks Edited May 21, 2008 by 98_shee Quote
Wildcardracing Posted May 21, 2008 Report Posted May 21, 2008 What type of port are they, reason I ask is because they may be able to be re-ported for the additional stroke which would be the best way. My advice is to sell your ported cylinders and get some vigin ones ported for the 4mil. As it is now the piston is 2mm below the floor of the ports at BDC, if you run a spacer it will be even lower which should hurt performance. Quote
98_shee Posted May 21, 2008 Author Report Posted May 21, 2008 Im not sure of the port they came on another shee that i sold, the bike runs great just wondering if it would benifit me to run the spacer plat, ftz ported the cylinders ive been to there site they charge around 600 to do port work, i just dont have the extra $$$$ to have another set ported. Quote
Wildcardracing Posted May 21, 2008 Report Posted May 21, 2008 Well, I'd say no to the spacer for 2 reasons 1)it will offset your floor to piston crown at BDC even worse 2)it's an other place for an airleak to form. Quote
98_shee Posted May 21, 2008 Author Report Posted May 21, 2008 Thanks man, that what i needed to know i'll just leave it they way it is. Quote
gregrob Posted May 21, 2008 Report Posted May 21, 2008 long rod or short rod has nothing to do with the domes you run. The fact that it is a 4mm stroke means you will need to have cut domes OR a spacer plate. The piston will come past the top of the cylinder anywhere from 1.65-1.75ish mm and your dome has to be cut or "offset" to compensate for that. Try to run the domes for a stock stroke and the piston will slam into it. Where is your compression now? If you're wanting more power you can get a set of domes made with a tighter squish to raise your compression. Have them setup for methanol or race gas and you would see an increase in power... Quote
jbooker82 Posted May 21, 2008 Report Posted May 21, 2008 long rod or short rod has nothing to do with the domes you run. The fact that it is a 4mm stroke means you will need to have cut domes OR a spacer plate. The piston will come past the top of the cylinder anywhere from 1.65-1.75ish mm and your dome has to be cut or "offset" to compensate for that. Try to run the domes for a stock stroke and the piston will slam into it. Where is your compression now? If you're wanting more power you can get a set of domes made with a tighter squish to raise your compression. Have them setup for methanol or race gas and you would see an increase in power... I think you miss understood him. His cylinders have been ported for a stock stroke build. He now has already ported cylinders (ported for stock stroke crank) with a 4 mill crank. He was just wondering if running non cut domes with a spacer plate would make more hp, becuase it will change the port timings. Since you physicaly move the jug up by adding a spacer plate. Quote
98_shee Posted May 21, 2008 Author Report Posted May 21, 2008 I think you miss understood him. His cylinders have been ported for a stock stroke build. He now has already ported cylinders (ported for stock stroke crank) with a 4 mill crank. He was just wondering if running non cut domes with a spacer plate would make more hp, becuase it will change the port timings. Since you physicaly move the jug up by adding a spacer plate. What he said.^^^ :thumbsup: Quote
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