Blacksmith Posted February 12, 2004 Report Share Posted February 12, 2004 Guys, I am running 19 cc domes on a bike with stock internals. This gives me about 161 lbs of compression at 3000 feet. For this setup I have been running 93 oct pump gas. However, I have been told that when I drop down to 1500 feet I will be over 175 psi and will need to run better fuel. There is no way that I can afford to run $5 a gallon 110 oct race gas so what I am wondering is can I use 104+ additive or perhaps avgas? Will a stock crank hold up under 175 lbs of compression, or do I simply need to come up with the cash for a set of 20cc domes? Thanks for the input. Quote Link to comment Share on other sites More sharing options...
Toomey Banshee Posted February 12, 2004 Report Share Posted February 12, 2004 Its not just the question of will your crank hold up, over time it wont, but your top end wont hold up in the here and now. Anything flirting around 160 lbs I would run a mix of 50/50 race and 93 or 94. Anything NEAR 170 I would run straight race. If anything I would throw in some 21's if you still want to be on pump fuel. Quote Link to comment Share on other sites More sharing options...
51222 Posted February 12, 2004 Report Share Posted February 12, 2004 yeah iam totally with Toomey Banshee i guess 20 cc domes will also work u can always contact ur head manufacture and they will give you every detail u need Quote Link to comment Share on other sites More sharing options...
jsekula Posted February 19, 2004 Report Share Posted February 19, 2004 Guys, I am running 19 cc domes on a bike with stock internals. This gives me about 161 lbs of compression at 3000 feet. For this setup I have been running 93 oct pump gas. However, I have been told that when I drop down to 1500 feet I will be over 175 psi and will need to run better fuel. There is no way that I can afford to run $5 a gallon 110 oct race gas so what I am wondering is can I use 104+ additive or perhaps avgas? Will a stock crank hold up under 175 lbs of compression, or do I simply need to come up with the cash for a set of 20cc domes? Thanks for the input. Check you numbers... You should be at 145 @ 3000 w/ 19cc domes. http://www.thebansheezone.com/Bansheezone/CoolheadChart.htm If you don't have one, get a compression gauge to verify your numbers and save some grief... your probablly about 154 @ 1500 Otherwise I agree with Toomey Banshee Quote Link to comment Share on other sites More sharing options...
yamaha350 Posted February 19, 2004 Report Share Posted February 19, 2004 my buddies banshee has lasted 2 years on a stock top end with 19cc domes. and he only runs on sand at sea level. and he runs avgas. avgas is half the price of race and in my opinion it is better. Quote Link to comment Share on other sites More sharing options...
boonman Posted February 19, 2004 Report Share Posted February 19, 2004 Without getting into the Aviation fuel disasterous argument, you will need race fuel with 19cc domes. BUt, grab yourself a compression guage and check for yourself. Also, while your at it, check your squish as well. These two factors can most of the tme determine your octane requirements. If you do in fact have 160 at 3,000', you will most certainly need high octane fuel.... Quote Link to comment Share on other sites More sharing options...
Fever Posted February 19, 2004 Report Share Posted February 19, 2004 AV gas makes airplanes fly...not atv's Quote Link to comment Share on other sites More sharing options...
Aussie Quad Racer Posted February 19, 2004 Report Share Posted February 19, 2004 yeah and if its good enough to keep planes in the air then its good enough for your quad Quote Link to comment Share on other sites More sharing options...
sredish Posted February 19, 2004 Report Share Posted February 19, 2004 yeah and if its good enough to keep planes in the air then its good enough for your quad I've never actually used the stuff. Is there much benefit if you don't have the necessary compression. I think I'm at 150, give or take. I'm going to check tonight, because I just realized I forgot. My problem is, with work, I never know if I'll have time to ride, and sometimes it may sit for a week or two. I'd hate to buy a jug of gas and it just sit, and if I buy a small amount, and I run out, that really sucks. Quote Link to comment Share on other sites More sharing options...
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