kodie Posted April 29, 2009 Report Share Posted April 29, 2009 4 mil trail port chariot head with 22cc cut domes +4 timing 830 above sea level and stock bore compression is 160 do I need pure 110 or can I mix some 94 into it? Also If I need pure 110 will taking my timing back down to stock allow me to use 110 mixed with 94? Quote Link to comment Share on other sites More sharing options...
donkeypuncher Posted April 29, 2009 Report Share Posted April 29, 2009 i would say that your probly just fine with runnin straight pump gas. but if you feel like runnin race gas then you could mix it 50/50. no need to run straight race fuel with just 160lbs of compression. Quote Link to comment Share on other sites More sharing options...
kodie Posted April 29, 2009 Author Report Share Posted April 29, 2009 i would say that your probly just fine with runnin straight pump gas. but if you feel like runnin race gas then you could mix it 50/50. no need to run straight race fuel with just 160lbs of compression. well it was .80 over and I was running pump gas and it fried my pistons. so had to resleeve it. just got the juggs back last night and she started on the 4th kick. is there much of a difference in compression from 80 over and stock bore? Quote Link to comment Share on other sites More sharing options...
spurdy Posted April 30, 2009 Report Share Posted April 30, 2009 well it was .80 over and I was running pump gas and it fried my pistons. so had to resleeve it. just got the juggs back last night and she started on the 4th kick. is there much of a difference in compression from 80 over and stock bore? Bore size wont effect compression. At least not so much that it will matter. Static compression is derived from the volume you are compressing from when the exhaust port is closed to volume when the piston is at TDC. Having a piston 0.010" or 0.080" smaller than what you had before is minimal volume difference. More likely you may need to look at the compression ratio (dynamic compression) and there is a formula on here to calculate that (do a search). I would say based on your mods you could probably run pump fuel or maybe have a need for a 50/50 mix but not straight 110. What exactly do you mean by "fried your pistons"? There are several things that can cause piston/ring failure besides fuel. SP Quote Link to comment Share on other sites More sharing options...
fastrthnu Posted April 30, 2009 Report Share Posted April 30, 2009 94 is right near the border line for 160 and +4 timing. If I had a billet impeller, cool head, and engine ice, Id feel safe running 94 with it. you dont need to run 50/50 either, mix it to equate 98 and youll be good to go for sure w/o wasting so much go race juice. How many kicks does it take to start now with the carbs all primed and all? If its still 4 kicks on a fresh top you got somethig else wrong. esp with 160psi comp. Quote Link to comment Share on other sites More sharing options...
UnrealBanshee Posted April 30, 2009 Report Share Posted April 30, 2009 so i got vito cool head and 34 kiehin carbs 4 degree advanced timing and the guy i bought it from told me i need to run 105 octane...but its hard to find around my town and inconvienent so what i did was bought 94 octane and a orange bootle of that octane booster...your supposed to put a whole bottle in 15 gals of gas but i put the whole bottle in 5 gal of 94 octane then mix it as i need it with castor...what im getting at is this octane booster gonna hurt my bike and is the way im mixing it helping my octane go up? Quote Link to comment Share on other sites More sharing options...
fastrthnu Posted April 30, 2009 Report Share Posted April 30, 2009 Im going to run VP red/93 @ 101-103 in mine at 182psi. 105 in a 160lb motor is overkill by far! Quote Link to comment Share on other sites More sharing options...
UnrealBanshee Posted April 30, 2009 Report Share Posted April 30, 2009 so i got vito cool head and 34 kiehin carbs 4 degree advanced timing and the guy i bought it from told me i need to run 105 octane...but its hard to find around my town and inconvienent so what i did was bought 94 octane and a orange bootle of that octane booster...your supposed to put a whole bottle in 15 gals of gas but i put the whole bottle in 5 gal of 94 octane then mix it as i need it with castor...what im getting at is this octane booster gonna hurt my bike and is the way im mixing it helping my octane go up? Anyone? Quote Link to comment Share on other sites More sharing options...
spurdy Posted April 30, 2009 Report Share Posted April 30, 2009 Anyone? I wouldn't use octane booster period. Just my personal preference. At the end of the day race fuel isn't that much. I spend about $500 a year on race fuel vs $300 on pump fuel. Just my 2 cents. SP Quote Link to comment Share on other sites More sharing options...
UnrealBanshee Posted April 30, 2009 Report Share Posted April 30, 2009 I wouldn't use octane booster period. Just my personal preference. At the end of the day race fuel isn't that much. I spend about $500 a year on race fuel vs $300 on pump fuel. Just my 2 cents. SP will it hurt my bike ? Quote Link to comment Share on other sites More sharing options...
spurdy Posted April 30, 2009 Report Share Posted April 30, 2009 will it hurt my bike ? I wouldn't risk it and that would be my concern. But I'm not an expert. SP Quote Link to comment Share on other sites More sharing options...
kodie Posted April 30, 2009 Author Report Share Posted April 30, 2009 What exactly do you mean by "fried your pistons"? There are several things that can cause piston/ring failure besides fuel. SP 94 is right near the border line for 160 and +4 timing. If I had a billet impeller, cool head, and engine ice, Id feel safe running 94 with it. you dont need to run 50/50 either, mix it to equate 98 and youll be good to go for sure w/o wasting so much go race juice. How many kicks does it take to start now with the carbs all primed and all? If its still 4 kicks on a fresh top you got somethig else wrong. esp with 160psi comp. I do have high flow impeller cool head and engine ice. And since first start it fires up on 1 kick. Quote Link to comment Share on other sites More sharing options...
Oregon Banshee Posted April 30, 2009 Report Share Posted April 30, 2009 (edited) How was your crank was everything tight with no play? it looks like your piston was hitting your dome. make sure you do a leak down test to make sure you have no air leaks and save your self from going through another top end. Just some ideas there for ya.... I wouldn't run a octane booster. I run a 50/50 mix of 94/110. I don't know if running a octane booster with hurt anything though? Anyone??? Edited April 30, 2009 by Oregon Banshee Quote Link to comment Share on other sites More sharing options...
kodie Posted April 30, 2009 Author Report Share Posted April 30, 2009 We did leak down it was all good. Crank was good to just fucked up the pistons domes and sleeves. I asked jeff at fast and he said 94 should be good. Thanks guys Quote Link to comment Share on other sites More sharing options...
deckheight Posted April 30, 2009 Report Share Posted April 30, 2009 The piston that didn't grenade was running way hot and detonating hard... Bunch of blow-by past both rings, hard dark black cooked oil on the crown. I'll bet there is a spot of cooked oil underneath about the size of a half dollar. Pretty obvious what happened to the other one. If it were me I would start out with the 100 octane this time. That 100 octane is cheap compared to a new top end. Another thing to think about is that you have a way better than average chance that there are pieces of ring down in the cases now... Quote Link to comment Share on other sites More sharing options...
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