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Has anyone used 100LL(100 octane low lead) in their motorcycle.Manual calls for 95+ octane and we only have 91 here in ca.

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Yes. A drawback is that 100LL is leaded fuel, therefore your plug and cylinder will be prone to lead deposits. How fast this builds up depends on your jetting and use. Lead build up may not be an issue over the life of the cylinder and piston between rebuilds but I would check the plug at a safe interval in order to observe the trend.

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Ive been running leaded gas since Ive had it and no problems with build up. Prolly has about 30 hours on it.

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I've used 100LL over the years both straight and 50/50 mix. I've never heard of anyone having problems because of lead. Actually, the lead acts as a prolonging agent to some degree.

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AVGas, most common 100LL, is not race fuel. It is disigned to run in engines that run at constant, reletively low RPMs. Its a good quality fuel, but you really won't gain any power and the blue dye makes a mess out of FCRs. I used to run it in my WR250 (2stroke) It was a great fuel for that bike in the woods because it totally smoothed out the monster hit. Everyone liked riding behind me because I smelled so good :cry: It will leave a lot of lead depositis in the motor, 100LL still has a high lead content compared to most race fuels.

Here is a write up a found a while back reguarding the subject:

"Avgas is less dense than most racing gasolines. Instead of weighing about 6.1 to 6.3 pounds per gallon like racing gasoline, it weighs 5.8 to 5.9 pounds per gallon. The racer must compensate for this by changing to richer (larger) jets in the carburetor when changing from racing gasoline to avgas.

The other major difference is octane quality. Avgas is short on octane compared to most racing gasolines. Many racing engines with "quick" spark advance curves or with no centrifugal advance have more spark advance at low rpm than avgas and some racing gasolines can handle. The result is detonation, especially during caution periods in circle track racing because all of the spark advance is "in", rpm is low, and part throttle air fuel ratios are too lean for the operating conditions. If the driver does not "work" the throttle back and forth, pistons can be "burned" which melts away part of the aluminum piston material. Inadequate octane quality is one of the quickest ways to destroy an engine. Pistons can be severely damaged during one acceleration where detonation is present and the racer may not know what is happening until it is too late.

For maximum performance and power from a racing engine, racing gasoline will normally provide better performance than avgas. Avgas can be a good gasoline for some applications, but since most racers do not know the octane requirement of their engines, they would be better off with a "real" racing gasoline that will give them the overall resistance to detonation that they need to protect their investment. If someone has spent from $15,000 to $50,000 or more on their racing engine, it is foolish to cut corners on gasoline be sure you have a gasoline with adequate octane quality."

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Has anyone used 100LL(100 octane low lead) in their motorcycle.Manual calls for 95+ octane and we only have 91 here in ca.

i can say without hesitation or qualification that AvGas works great in low compression engines like air cooled 4 strokes and stock 2 strokes. IMO, it works much better than pump gas but not quite as good as race gas. however, it costs less than half of the cheapest race gas and only a little more than premium unleaded.

about lead deposits: untill the AMA banned leaded fuel every race gas on the market was leaded, so i find the whole supposed lead-deposit issue to be bullschidt.

FWIW, i do not own a high performance 4 stroke so i can't say 1st hand, but i've heard mixed reviews of AvGas in modern 4 strokes. i can say unequivocally that it made a dramatic improvement in ease of starting and throttle response in my XR600R.

EDIT - if you're using pump gas, you may have to re-jet. i found that AvGas leaned my jetting.

jeremiah

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get 110 oct race fuel (i use cam2 but theyre all fine) and mix it with hi test pump gas. mix it one part to one part. thats hundred octane fuel right there. if you feel like saving on race fuel and feel like doing mathe just figure out how much 110 combined with how much 91 will average 95 and your good to go

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I mix 110 leaded race fuel with the 87 pump gas for our KXF250 with a Wiseco Hi-comp piston. Too much octane will hurt performance. Never had any deposit issues when running 110 straight. 110 is easier to get around here. I use it mostly hoping the lead will help with the intake valve issue. It does run leaner also than 93 pump gas.

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It will leave a lot of lead depositis in the motor, 100LL still has a high lead content compared to most race fuels.

if you actually check, you will find that most vp fuels contain substantially more lead than avgas. i posted a link to vp's specs the last time this came up.

mw

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I wouldn't suggest the use of aviation fuel.

For automotive high performance forced induction applications I have always used Toluene to create a homebrew high octane fuel. Toulene is a very common ingredient in octane boosters in a can. Realize that 12-16 ounces of octane booster in a can will only raise octane 2-3 *points*, i.e. from 92 to 92.3. The aromatic content of pump gasoline is defined by ASTM D4814, which specify an aromatic content of between 20% and 45%. Since toluene is the major aromatic component of pump gas, there is plenty already on board at the pump.

You can purchase Toluene by the gallon at many paint supply stores (Sherwin Williams) for around $2.50-$5.00/gal. Assuming 92 octane pump fuel with a mixture of 30% Toluene results in 98.6 octane. This calculation is based on that Toluene is 114 octane.

Toluene was used extensively back in the 1980s by all the Formula One teams as a 84% mixture. BP of Australia actually recommends the use of Toluene <30% mixture as an octane booster. http://www.bp.com.au/products/fuelnews/faq.asp#1

The Buick Regal site has some information as well:

http://www.gnttype.org/techarea/misc/octaneexplained.html

Here is a good general FAQ on gasoline: http://www.mr2.com/TEXT/gasoline_faq.txt

There is tons of information on this subject if you search on google.com or any forced induction automotive forum.

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i looked into using AVGas in my hot rod chevy truck. i was told that the lead content will acutally damage the valve and the valve seats. in the long run AVGas is not worth it.

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FWIW, lead is good for 4-strokes. The whole reason that lead was introduced to fuel was to provide valve and top end lubrication. I run leaded race gas mixed 3:1 with 92 octane unleaded in my DRZ with 13.5:1 piston. My valves have not budged one bit.

The value of lead far outweighs any downside, unless you factor in the environmental concerns.

Also, I've heard that avgas contains additives, such as de-icing agents that can be harsh on the carb and such over the long term.

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Anyone who claims that the lead deposits are bunk had obvioulsy never torn apart a motor after using leaded fuel. I ran nothing but unleaded pump gas in my WR250Z motor was alwas deposit-free. Started running AvGas (100LL) continued running it for a whole season. Tore the motor down, WOW what to yah know, lead deposits on the rod, coating the intake ports & sides of the case next to the crank. If I had pic I'd post it.

Avgas also has a high alcohol content, to displace moisture. It is also formulated to enable high altitude operation. AvGas, Race fuel & Autogas are very different in formulation, about the only thing they have in common is that they burn and let us go fast :cry:

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