Running Avgas 100LL Comments?
Posted July 04, 2004 - 06:04 PM
Posted July 04, 2004 - 07:23 PM
People usually run that stuff when they have modded their motor with super high compression, etc and they need the higher octane to stop it from knocking
Posted July 04, 2004 - 08:04 PM
Here's a direct quote from Team Honda's Bruce Ogilvie when he listed various tips from testing and racing the XR650R. I wouldn't take his comments as gospel, but it's something to think about.
"A stock XR650 will run better on pump gas than a high-octane race fuel, which needs a higher compression ratio to be effective. (All gas in the Honda pits is Chevron 92- or VP 93-octane unleaded.)"
Posted July 05, 2004 - 06:00 PM
You can take Ogilvie's word for gospel, trust me.
No one knows more about the 650R than him and his team.
Those opinions were formed from racing, a lot of racing.
The only time they run higer octane is when they pump up the compression.
Their Baja 1000/2000 pre-run bikes ran 110-114 MPH on pump gas and stock compression.
Posted July 05, 2004 - 06:09 PM
L.L. '00 XR650R
Posted July 05, 2004 - 09:24 PM
Posted July 05, 2004 - 09:54 PM
But racing, you run what you can get
Nova / blue
Magna sin / green
Premium / red
Posted July 06, 2004 - 03:47 AM
2) it keeps forever. gone are the days of varnished or gummed up carbs.
3) it works excellent in my 600R.
4) contrary to jetpilot's assertion, AvGas works best (from my own observations and informal surveys) in low compression engines like un-modded XRs and 2 strokes. it tends to run lean and bog in high compression engines.
5) of course you don't "need" to burn AvGas. pump premium works great in XRs, but AvGas works better: better throttle response, easier starting, etc.
6) i run a 60/40 mix of AvGas/pump gas in my 2 stroke. for the sake of convienence i use the same (not pre-mixed) gas for my XR. i've never run it straight.
7) give it a try. just top off your tank once and then let us know how it worked for you. you'll be surprised how full of it the nay-sayers (who have not or do not burn AvGas) are.
Posted July 09, 2004 - 03:30 AM
Posted July 09, 2004 - 06:09 AM
Case in point: I did a trip to Cabo and brought 20 gal's of Avgas for my 600. The bike ran better on 93 Pemex, started easier and smoother than on the 100 avgas.
Posted July 09, 2004 - 11:46 AM
I'm not one, and I know from facts (read many a thing on this to win a bet 3yrs ago)... that Aviation Fuel is VERY DRY. The lubrication of the fuel sucks for a two stroke or four stroke... and the 4strokes don't benefit one bit.
I'll take a Pump gas Premium over any AVgas anyday. But that's me. Same reason cars/vehicles are made not necessarily to run on Premium... and when you run premium your cars are running richer (unless stickered "premium unleaded fuel only")
Why do you think when you buy a "chip" for your car... making it faster and more performance related, that they require you to run premium?! Besides knock and ping, it's been remapped to run rich, or leaned out a tad for the premium fuel. (come on guys... tell me if I'm blowing smoke here!)
There's a lot of myths about AVGas, high octane fuels and standard pump gas in stock four strokes. I wish someone had all the answers and could put us all in the think tank.
Posted July 10, 2004 - 12:03 PM
Just because some engines need super high octane gas doesnt mean ALL engines benefit from it. AVGas is probably bad for the XR in the long run with no real advantage other than it having a longer shelf life. But then again I doubt anyone is buying 100LL because they want to leave the same tank of gas in thier tank for a year. So bottom line is no benefit in the way your XR will run, and a very real downside to using 100LL, but there is alwayws someone that cant figure it out
There is very strong consensus out there that AVGas is just not a good idea in the XR, with the exception of Beer Studd. There is always someone that will get an idea in thier head and twist the facts to fit what they "Beleive". Personally I respect and listen to guys who are capable of learning and putting aside their misconceptions.
Posted July 11, 2004 - 07:57 AM
And I'm for sure no expert in the subject.
Posted July 11, 2004 - 04:22 PM
besides that, she's an 85. if i get 19 years of easier starting and better throttle response instead of 25 years of harder starting and so-so throttle response, well then IMO that's a good trade.
FWIW - there is no "consensus" on AvGas being bad. that's just haters like you parroting what you heard some other expert say
Posted July 11, 2004 - 06:04 PM
1. Avgas IS a dry fuel and should be mixed with car gas for
use in a stock motorcycle engine. It will evaporate off
your hands like alcohol, leaving no smell.
2. Avgas has more lead than any car gas ever had at any time
3. A mixture of 2:1 will benefit the power output of a
motorcycle engine if said engine is compressing 10:1
or higher, however the avgas additives are for aircraft.
4. Avgas may in fact burn exhaust valves running it
straight, however a 2:1 ratio with car gas will provide
enough protection against that problem for a bike.
5. The 2:1 mixture will also provide the necessary car gas
additives which are also beneficial to motorycle engines.
6. Avgas is formulated for out-dated, very low compression
air-cooled aircraft engines and contains additives
specially made for those engines.
7. Avgas is much higher quality than any car gas
8. Shelf life is only slightly better than car gas. It will
still turn to varnish over time.
9. Running super-unleaded car gas in a motorcycle is the
safest solution, however a noticeable improvement in
upper rpm power output will be noted by running a mixture
of avgas in the bike. Additive protection will be reduced
I told the guy that when I tried a 2:1 mix of the avgas and super unleaded, that my bike did in fact run stronger in the upper revs, but got hotter and spewed a little coolant after I shut the engine off. He said that if I only ride the bike on weekends and don't run the engine for long periods at wide open throttle, then the fuel mix will not damage the engine. More deposit buildup and/or plug fouling might still occur however.
Posted July 12, 2004 - 03:27 AM
Beer stud says "FWIW - there is no "consensus" on AvGas being bad. that's just haters like you parroting what you heard some other expert say". Haters ? I dont hate avgas, used it in my plane all the time, but im just smart enough to know that its not for my XR. As as far as consensus, there sure is one heck of an consensus against using it in the XR, just another fact that beerstud is totally wrong about and to ignorant to see. But then again, thats exactly what I would expect from a person twists facts and immagines improved performance to fit what he WANTS to believe is true.
To give beerstud a little credit (which is hard), there are indeed a couple of upsides to AVGas. It has a neat blue color and a pleasing sweet odor... Has beerstud been adding 100LL to his beer as well as his XR ? that would explain a lot.
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