the question of alcohol has been raised a few times so I broke out my holley carberator handbook for cars . According to holley methonal can give you about a 9% increase in power but more can be had becasue of the tuning leway you can get with higher compression and/ or different spark timing. That is about the only plus unless youre making your own :confused:
The downside is
That storage of the fuel is hard since alchohol is going to try and soak up any water in the air.
Corrosion is a problem after you run the the methanol you should run gas thru the engine to remove all of the methanol if the engine is going to sit for a couple of days.
Methonal recquires 120% more fuel for a good mixture than gas . So if youre main jet is about 1/8 " in diameter you will need something about 5/16 in diameter for the main jet now.
Methonal is not kind to certain rubber seals & plastics so you might have to change you needle and seat<probably would have to anyway to get the flow > and floats.
camshaft and intake runner selection is more critical because the air fuel mixture is so heavy with fuel that the fuel might "drop out" of the air
that would be the information that I got from the books
Holley Carburetors&Manifold
HP Books
written by Mike Urich & Bill Fischer
Athough this information was written specifically with Holley carbs in mind for cars. I am sure the characteristics of alchohol would be very similar in any application of a carburated four stroke
Good info. I think , though, that the 120% rule would be applied to the area of the jet, instead of the diameter? A lot bigger than for gas, either way.
"Of course we have to pay the price of adding 130%more fuel.Again,because methanol is a little heavier metering orifices need only be 120%larger in coss-sectional area."
That sounds like to me that a carberator on a average dirt bike could not flow the amount of fuel that methanol recquires. Everything would have to be bigger, fuel supply line<shouldnt be rubber> needle and seat, pilot, needle jet /jet needle, and main. And of course fuel capacity of the float bowl would be suspect if running wide open for any length of time. The Holley book goes into great detail about how to use bigger stainless steel lines ,high performance pumps , fuel presssure regulators and a fuel return line to make sure that there is adequate fuel supply.
The book covers each topic of alchohol from storage to combustion chamber design and flame front and everything in between. It only covers each topic briefly making for easier reading but you get an idea of the forces your up against to get the power that could be had in it.
Sounds like it's more trouble than it's worth, for most people. No doubt there's a few guys out there who would try it just for the fun of solving the problems. I've also heard that methanol is very sensitive, jetting-wise, to weather changes.
Methanol in your bike??? Can't say I would do it. I have worked with methanol engines at the research lab where I work, and that stuff is super corrosive. Over time it will destroy even "methanol safe" parts. The real advantage to using methanol is that it allows such high compression ratios (we were running at over 19:1), so if you just dump it in your gas tank and try to run it, you aren't even reaping the benifits of the fuel. Just my 2 cents.
I would have to agree. The only way I would even think of messing with alchohol is if I had two bikes of the same make and model. If I had a bike that I could ride every weekend and then another bike like it with a lot of extra cash to throw at it I wouldn't mind going thru all the aggravation just to learn about alchohol but..........
If you're flat tracking,tt,dragracing, hillclimbing,etc. I think it might be worth a try. Many moons ago we played around with it when I worked at a Kaw. shop.(my dad was a petro. engr.for Valvoline Oil that helped) I also got involved with some hill climbers using methanol ,But the morel of the story is it cost alot,attracts moisture when not carefull, it does take a larger float bowel because you double the jet sizes,you change the oil every run(it gets contaminated from the meth.),the jetting changes easily with the weather(humidity&temp.),you have to advance the timing,it does make the engine run a lot cooler,along with everything else posted here. What little experience I had it was fun. If you insist on that methanol smell & a little small boost we'd run about 10% in our steet bikes,much more dose'nt stay mixed in gasoloine very well. Talk to some of the go-kart racers most of them run it
Just a thought :think:
D.E.A.
I used to run methanol in my KX250. Instead of modifying my stock carb, I used a double powerjet 40mm Lectron carb with their richest metering needle. This worked well. The bike made great power from mid to top and was excellent for power robbing sand tracks with long straights. Nothing short of an open bike would be able to run with it. I did mill the cylinder .015" to increase the compression and I advanced the ignition timing as well.
The down side is that methanol is hygroscopic, meaning it absorbs water straight out of the atmoshpere. I had to test the specific gravity of ever new batch of fuel. If it was too high the bike would run lean. At the end of every ride I had to run the methanol completely out of the carb, then run some gasoline w/ premix through it to remove the methanol from inside the engine. This is a lot of work after a hard ride.
In the end it was a fun experiment that worked well but made for a lot of extra work to stay on top of things.
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