Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: Maico500cc on August 18, 2010, 07:58:45 AM
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We run 2003 and some 2001 water-cooled along with some 1982 and older air-cooled two stroke dirt bikes. Would like to NOT to use pump gas with ethanol 10%, and could go to 15% if big brother has it's way. Looking at Turbo-Blue 110 pump with lead, or Turbo-Blue 100 Unleaded. Any thoughts?
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If your bike is stock I wouldnt recomend running high octane gas your bike can actually run worse. There was a website awhile back that showed gas stations that still have leaded gas I dont remember what though. lf anything try to find leaded gas or run a 50/50 mix of pump and race gas
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I try to avoid any fuel with alcohol in it it spoils to quickly. 100 octane is what my 2ts run best on including my chainsaws. I use a mix of VP 110 and pump gas 93 (no ethanol) octane at a 50/50 mix to get near this.Higher octane burns slower which will make your bike less responsive you may have to re-jet.Try the 100 blue and see what you get.One of the reasons for lead in fuel is to lube valve guides...but thats a 4t problem.
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http://pure-gas.org/ (http://pure-gas.org/)
I think this link should be made a sticky.
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Race gas mixed 50/50 with premium from a pump. Then a 32:1 premix ratio.
Runs great :D
[HD] When In Doubt Throttle Out (http://www.youtube.com/watch?v=lYoIejMnXyc#ws)
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If I wanted to get gas without ethanol, it looks like I'd have to burn an entire tank of the stuff, just to get to where I can buy it! I just use premium pump gas and then mix in the oil. I used to think we used 40:1 but it turns out my math was all wrong - we're at some weird decimal like 28:1.
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When I was racing in Iowa, I used only Turbo Blue, so don't have any fears of running that. It is very good. It was cheaper than VP and I had very good running bikes. It was also easier to find than VP fuels. Good luck.
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Where exactly can you buy 110 octane fuel? Or VP racing fuel, do any gas stations carry it, or would my local bike dealer carry it?
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My fuel is blue, 100LL Avgas, my bikes run just fine on it (especially the YZ490) and it's free.
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I use super unleaded with pj1 octane booster in the stock bike.Cheaper then c12.C12 in a race motor.Even my lawn tractor runs and starts better when i use that combo in it.todays gas is garbage for sure.
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sunoco leaded 110, its the purple stuff, my mechanic keeps a fresh drum in his shop so my fuel is always fresh. i would not trust race grade fuel from a pump station, god only knows how long its been sitting there. oh and i run my yz 32:1 mixed with rock oil syn2
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Ya, but where do you buy this stuff? At your dirt bike shop?
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My fuel is blue, 100LL Avgas, my bikes run just fine on it (especially the YZ490) and it's free.
Whose airplane are you syphoning fuel from? haha. I used to run the 100LL in my GSXR 1000, but I got it from my dad since he's a pilot and has easy access to the pumps. Still costs me $4.09 a gallon.
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My fuel is blue, 100LL Avgas, my bikes run just fine on it (especially the YZ490) and it's free.
Whose airplane are you syphoning fuel from? haha. I used to run the 100LL in my GSXR 1000, but I got it from my dad since he's a pilot and has easy access to the pumps. Still costs me $4.09 a gallon.
I'm an aircraft mechanic, when I work on the fuel systems I have to drain the tanks, I have about 75 gallons of fuel in my backyard right now ;)
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Johasus! Some people have all the luck, apparently.
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Never actually used race fuel but i heard if you dont keep it cool it goes bad. And i've also heard that race fuel does not increase performance, actually talked to blake whartons mechanic about it 2 weeks ago he said in a high compression head you have to run race gas and that it makes the engine run cooler. And running race fuel in a stock engine very well may make it run worse
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Never actually used race fuel but i heard if you dont keep it cool it goes bad. And i've also heard that race fuel does not increase performance, actually talked to blake whartons mechanic about it 2 weeks ago he said in a high compression head you have to run race gas and that it makes the engine run cooler. And running race fuel in a stock engine very well may make it run worse
That's true, higher octane fuel burns slower so if you don't have high enough compression to burn the fuel efficiently you have more unburnt fuel going out the exhaust and therefore less power. Too low of an octane fuel promotes detonation.
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riff, I keep hearing about detonation and things like my engine is pinging. What exactly is detonation?
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Detonation or pinging, is where the fuel charge is combusting before the spark plug can ignite it. It sounds a bit like someone put ballbearings in your combustion chamber.
It can be caused by a number of reasons, but mainly heat.
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Detonation or pinging, is where the fuel charge is combusting before the spark plug can ignite it. It sounds a bit like someone put ballbearings in your combustion chamber.
It can be caused by a number of reasons, but mainly heat.
yep that's it, and to expand on it... as your piston is traveling up the cylinder on the compression stroke the fuel/air mixture ignites before the plug sparks and tries to push the piston back down, sorta like smacking the top of the piston with a hammer
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Also, unlike normal combustion, detonation is rather violent. Normally, when the spark plug sparks it creates a small and slow-moving flame throughout the combustion chamber. This flame expands so slowly, in fact, that the piston would be at the bottom of its stroke by the time this flame managed to burn everything. Fortunately, the flame is hot, so after a very short time the heat from it causes the rest of the gas to ignite and you get a complete combustion. However, when detonation occurs, usually it's because there's just flat-out enough heat in the combustion chamber to ignite the gas in this manner, BEFORE the spark plug gets a chance to do anything. So instead of a slow burn that shoves the piston down, when your engine is pinging you just get a big bang that puts major stress on all the parts in your engine, and loses you power. And as if that weren't bad enough, pinging creates more heat which makes the engine more likely to ping on the next cycle!
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If it goes on long enough, it will put a nice, nickel-sized hole in the top of your piston. I know from experience!!! That's why ever since they went with 10% methanol even in premium 93 I mix in about a gallon of C12 with 3 gals of pump gas. The race gas is just much more consistent and make jetting easier.
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Wow lol thx for the info guys, that does sound violent for sure. I think I may be a little more wary on my gas selection now.
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Now I have a question. Doesn't ethanol have a higher octane (slower burn) than regular gasoline anyway? What is it about ethanol that makes it undesirable for these high-performance motors? Did they add 10% ethanol and then 5% water just to keep the octane down like it is?