What gas do you run?

[Robsauto]

Hey guys, I run VP C-12 in my 95 KX5. I just heard a rumor that the E.P.A is going to outlaw race gas in California. My bike pinged on pump gas, so I ran c-12. Here in so cal we only have 91 octane at the pump. Does anybody run pump gas here?

[Paul]

In my everyday KX I do BUT... that bike has had the Eric Gorr head modification. My race bike runs on a 50 - 50 mix of 91 and Sunoco Purple (110 octane). That works out to 100.2 - or so the calculator says - and the black / white race bike is happy with that.

[Sharc]

I run Premium anything gas in my 2002 and no pings...I'm a crazy old-school guy though - Golden Spectro at 50:1, any brand premium gas from any station thats open....havent fouled a plug, pinged, or fried a top end since the bike was new 4/02...the sweet K5 sucks it up and spits it out...!!

Sharc

[teamgreen500]

I run 50:50 pump gas/76 110 race gas w/ Maxima Super M. My top-ends are doing real good...even after "Too many hours". Haven't heard about the "no race gas" thing. If so, I'll just go visit my friends up in Oregon and buy a drum.

The head mod's are a good idea and on my last "pump" motor, those mod's produced more/quicker rev's than stock.

Manny

[Sharc]

TeamG -Who did your head mod...Eric Gorr...? I've seen mixed reviews of his work. I have a friend with a KTM 310 ala Eric G. It blew up the first time, fixed it free, now runs like a mofo (faaaassst...!)

[teamgreen500]

My last "Mod-head" was in '91. It was done by Jon Stoodley, my first and best race mechanic! He "Bumped" my KDX up and "Bumped" my KX down on compression.

You can find him over at the Gas-Gas Trials Bike/U.S. site: www.gasgas.com (Go to right side of the homepage,"GasGas Guru...)He's the "Tech-Questions" guy over there!

Go ask him and have him do it. You won't find a better engine tuner. He treats every motor like a works motor.

Best of luck,

Manny

[Robsauto]

Thanks for the info. Sharc I am amazed you don't ping on pump gas. You wont hear it ping if you ride mx, but in the desert, when it gets hot as in a long hi-speed sand wash, mine pinged no matter how i jetted it. Kawasaki sells 3 different head gaskets for the kx5, so i will try the thick one (1mm) and see if it will help.

[Rick]

It's important to remember that the farther you are from sea level the lower Octane required.  For instance, in my Corvette, I have a 327 small block with 11.5:1 forged pistons.  At 4000 feet elevation, I can get away with 92 Octane Chevron.  However, when I take a little drive towards the coast, I'm  looking for Octane boost just so she'll idle.  I did try and use 85 Octane once, but had to siphon it out and add the good stuff, as it wouldn't even idle.

Same goes for the 500.  Higher elevation means the bike is less sensitive to Octane rating.  I used to run VP exclusively, riding and racing.  After several years, I switched to 92 Octane Chevron for the bike.  If we head for Southern California for a race at sea level (or close to sea level), we step up to VP one again.

Rick

[John]

I seem to recall    that the octane level is (relative to / indicative for) the point of self combustion. The higher number the less likely to self combust. The higher octane - the more you can compress the air / fuel mixture before it self combust. Pinging engines where everything is OK benefits from an octane boost (high compression setups).

This is something I remembered from school; maybe some aviation techie can correct me if I'm wrong?  

/John

[HULKSTER]

I run Premium anything gas in my 2002 and no pings...I'm a crazy old-school guy though - Golden Spectro at 50:1, any brand premium gas from any station thats open....havent fouled a plug, pinged, or fried a top end since the bike was new 4/02...the sweet K5 sucks it up and spits it out...!!

Sharc

Me too....me too....

[mikesmith]

I run Chevron (pretty shure in Nor Cal its only 91 octain)and as long as Its jetted spot on no ping with out any head mods and stock gasket thickness.And it gets HOT up hear in the summer.