91-98-avgas

[neil_cb125t]

hey i run and always have run 50/50 mix. I only got real gains once i raised the compression ( and bored it out and blah blah blah ) in my ZXR400.

I also know a bit bout avy ( as im in the Airforce ) All the post pre this are correct - its designed for LOW Rpm and high altitude. Both of whcih we dont use!!

But Simply put if your bike is standard then you wont really gain alot from the xtra $$ your spending.

Mossey will agree that my "little bumble bee" has enought go... if its standard run it on 96-98. Save up then bore it out its the best EASIEST mod to do if you want power. 65hp straight to 75hp.

[mossy1200]

hey i run and always have run 50/50 mix. I only got real gains once i raised the compression ( and bored it out and blah blah blah ) in my ZXR400.

I also know a bit bout avy ( as im in the Airforce ) All the post pre this are correct - its designed for LOW Rpm and high altitude. Both of whcih we dont use!!

But Simply put if your bike is standard then you wont really gain alot from the xtra $$ your spending.

Mossey will agree that my "little bumble bee" has enought go... if its standard run it on 96-98. Save up then bore it out its the best EASIEST mod to do if you want power. 65hp straight to 75hp.

You might need more Neil.Nitro maybe.Carved 9kg off my fat boy and added 5hp and more torque.If that doesnt work im going to the gym.
I tried the av gas last year and found more grunt going back to pump gas.

[SARGE]

Ok you guys before anyone says look in search i have but my question is for my bike.
86 gsxr400 in pre 89 i have been running it on 98 but have just aquired some avgas.It seems to run ok down the drive [only just put it in ].
The manual says 85-95 octain or higher and unleaded or low lead recomended.
From whot i understand avgas is low lead now is this true?
So question: will it run ok on pure avgas or a mix without detrimental effects on the motor?.
Question 2: does avgas run richer or leaner than petrol?
Cheers for any advice im a noobe to racing and want as much performance without risking blowing the motor up through lack of knowledge so am here to ask the experts.

i dont race but i run Av (from the airport) in my street bike .


saying that though.. it is slightly higher compression than standard


it IS a 'slow burn' fuel though .. low temp flame fronts .. i mix in some Acetone to boost the flames fronts within the chambers

[sugilite:Me]

You lose low end power with 100% av gas due to that pre mentioned long burn time. 91 has very short burn time. Running a 70% av gas 30% 91 remedies this.

[kiwi cowboy]

hey i run and always have run 50/50 mix. I only got real gains once i raised the compression ( and bored it out and blah blah blah ) in my ZXR400.

I also know a bit bout avy ( as im in the Airforce ) All the post pre this are correct - its designed for LOW Rpm and high altitude. Both of whcih we dont use!!

But Simply put if your bike is standard then you wont really gain alot from the xtra $$ your spending.

Mossey will agree that my "little bumble bee" has enought go... if its standard run it on 96-98. Save up then bore it out its the best EASIEST mod to do if you want power. 65hp straight to 75hp.

ok seems the avgas aint fer me so back ta 98 it it after all im out fer fun fun fun till i get somit bigger lol cheers all you guys that postedthat was a mannot a gayby the way

[I14]

What about running 10% toluene (used to be called methyl benzene in the old ads) in 98? It lifts the octane number and has no lead of course but again I assume unless the compression is raised and/or the timing is advanced then no benefit will occur? If you google its use in petrol you will find plenty of posts (mostly in the US) on its effectiveness.

[neil_cb125t]

9KG OMG!! i wish i could find that in mine - im getting maybe 800 grams out of my rear sprocket - got a kilo from my carbon pipe.... just getting my Airbox sorted - hmmm maybe i should try Sp cams that should be another 3-4hp.

Long track sounds like a good testing ground for us ....... less straights.....

see you there dude!!

You might need more Neil.Nitro maybe.Carved 9kg off my fat boy and added 5hp and more torque.If that doesnt work im going to the gym.
I tried the av gas last year and found more grunt going back to pump gas.

[mossy1200]

9KG OMG!! i wish i could find that in mine - im getting maybe 800 grams out of my rear sprocket - got a kilo from my carbon pipe.... just getting my Airbox sorted - hmmm maybe i should try Sp cams that should be another 3-4hp.

Long track sounds like a good testing ground for us ....... less straights.....

see you there dude!!

Neil my stock exup header pipes were 9.2kg now yoshi under 3 and airbox fell of bike while on dyno 3kg.Sounds like more little straights just shorter each one.LOL .If i ever learn to ride there will be trouble......
Just 12 more sleeps..See you there.

[Peter Smith]

Carved 9kg off my fat boy

Oh, sorry Mossy, I thought you meant you lost 9kg, not your bike.
It might be worth coming down to Manfield just to watch you and Neil.
Ya gotta keep them little bikes behind ya. Mojo at stake and all.

[GSVR]

hey i run and always have run 50/50 mix. I only got real gains once i raised the compression ( and bored it out and blah blah blah ) in my ZXR400.

I also know a bit bout avy ( as im in the Airforce ) All the post pre this are correct - its designed for LOW Rpm and high altitude. Both of whcih we dont use!!

But Simply put if your bike is standard then you wont really gain alot from the xtra $$ your spending.

Mossey will agree that my "little bumble bee" has enought go... if its standard run it on 96-98. Save up then bore it out its the best EASIEST mod to do if you want power. 65hp straight to 75hp.

If its standard it will probably run on 91 if the mixture and timing are right. The addition of the avgas is mainly to get the antiknock properties.

The biofuels may make a bit more power too but you have to run a little richer.

As you say getting a 450 bore and fresh well tuned motor will make massive gains compared to the little you will get from running the best fuel. That and good handling, tyres, and weight savings. Oh and good riding skills is always a help too.

[mossy1200]

Oh, sorry Mossy, I thought you meant you lost 9kg, not your bike.
It might be worth coming down to Manfield just to watch you and Neil.
Ya gotta keep them little bikes behind ya. Mojo at stake and all.

If your coming to watch bring your bike you girls blouse.You still got couple days to post your entry.Im sure i found 0.07 of a second
If Neil keeps beating me ill start buying him hotdogs to weigh him down a little.

[quickbuck]

I also know a bit bout avy ( as im in the Airforce ) All the post pre this are correct - its designed for LOW Rpm and high altitude. Both of whcih we dont use!!

So what exactly do you do int he Air Force???


The posts that are correct are the ones that say AvGas has a very high lead content. 4 Times that of the old 96.
AvGas also Burns slower.
The 100 means Octane rating (Research Octane Number).
There is another test called Motor Octane Number.
This is when they blend Iso Octane with Normal Heptane in a proportion to work out the knock value of a fuel. Ie 91 was 91% Iso Octane and 9% Normal Heptane.... etc etc ...Blah Blah.....

The posts that are slightly misguided are the ones that confuse Octane Rating to Calorific Value.

To Add to the list of Aircraft engines...
TVO435 (Turbo Charged Vertically Mounted 435 CuIn 6 Cylinder) pokes out 280BHP Max. 220 BHP cruse @3200 RPM.
Yes, each pot is over ONE LITRE!
Also the lead will fowl your little plugs.....

My advise is mix it with 91.
Get used to servicing your plugs.
BTW the plugs on Aircraft engines are cleaned every 100 hours.
That would be approx 6000km on your bike....
Also the plugs are HUGE and allow a bit of deposit on them.....

[Peter Smith]

If your coming to watch bring your bike you girls blouse.You still got couple days to post your entry.Im sure i found 0.07 of a second
If Neil keeps beating me ill start buying him hotdogs to weigh him down a little.

Ya don't really want to come 3rd, do ya, behind me and Neil.
Seriously though, I need to save some money for next season, I might sell the Katana as well.
I'll be checking the results, SO YA BETTER WIN.

[dangerous]

The "octane" figure is it's resistance to detonation (anti knock value)
I've had access to avgas for the last 18 years.... and wont touch the shit to run in my road vehicles

interesting and a guy in your situation of relying on good gas would know...
I have noticed a mid power increase in some of my engines, older Japers slower reving higher compresion, cept for the CX500 Turbo... but that certinly prefered it.
To answer 'the' question in a high reving muilty... no advatage acept for the below.

There is an advantage to avgas that no one has mentioned. Because you cannot get out and push if an aircraft engine stops because the fuel has water in it, it must be guaranteed not to have water in it. If you get it from a certified supply source at an airfield you can be reasonably sure that it has been stored in good conditions.

and this also with the fact it is +/- 5% compeared to +/- 15% acurate octain means you can tune a engine much beter due to the MUCH higher quality. I never had carbon issues, Lead as you know is a natural coolent/lube and oct booster.


This being the reason I run avgas in my race bikes, I doubt it very much that I have any performance advantage with HP, but I do know that when using it in my strokers it means a far more relible BOOM, same reason I use a fully syn oil.

[neil_cb125t]

Cheers - i still cant keep with your 'missing' thing thou!! I have noticed with the addition of my flat slide even thou i gain nearly 5 hp i didnt really get anymore straight line speed - but my roll on drive out of the corners is SO MUCH better!!! I dont quite understand that//.....

As you say getting a 450 bore and fresh well tuned motor will make massive gains compared to the little you will get from running the best fuel. That and good handling, tyres, and weight savings. Oh and good riding skills is always a help too.[/QUOTE]