Leaded gas and synthetic oil

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Jun 5, 2003
Apple Valley, California
I read here somewhere that certain synthetic oils are not compatable with leaded gas.

Said that the syn oil cant clean the lead out of the ring lands.

Here is my problem. I have a Hi-Performance 4-stroke atv. I has 11.3-1 compression from the factory.

It has a sticker that says 92 octain or higher. I can only get 90 octain at the gas station and the bike pings on it.

I don't want to burn a hole in my piston (again!). So I'm toying with the idea of mixing some race gas with the 90 octain unleaded to increase the octain a few numbers.

I cant find unleaded race gas, only leaded and I'm running Mobil-1 10w-40 oil.

So can I run leaded gas with this oil?

Also say I mix one gallon of 100 octain race gas with one gallon of 90 octain do I get 95 octain?
Do they sell toluene or xylene in the stores there? I remember I couldn't find any methanol for sale at the hardware stores in CA. Those wouldn't leave any deposits.
Not an issue. IIRC some early ester based synthetics had troubles holding lead "in solution".

Think about it this way: Redline synthetic racing oil and racing gas. No problem. Amsoil, Mobil1 no problem

However, I'm not sure Av gas is your best choice.

You should be able to get 92 octane, no? If so mix with fuel power and xylene.
Isn't aviation fuel based off kerosene?

Don't worry about synthetics...I whole-heartedly recommend Redline racing oil SAE 40. Looks like a very, very good oil in a racing application.

My two cents...buy 90 octane from the local pumps, but find a good octane booster since you say detonation is a problem.

Originally posted by userfriendly:
Hole in piston maybe from lean mixture.

I dunno. I blew the bike up 3 days out of warranty.

I ended up rebuilding it myself and it has been fine for 2 years untill they switched over to the "Winter gas"...Now it's rattling.
The reason av gas came up in my post is part brain fart and partly because the issue with leaded gas and some syn oils was an aviation issue.

No they aren't the same.

The nice thing is, you have a relatively small gas tank. So get the 90 or 91 octane, and add the appropriate amount of FP, xylene, etc mix...as for ratios....well ask Molacule.
I have a home brew mix for like 10 gallons of fuel.

I would do like 1.5X the recommended amount of FP.
Xylene.....hmm...don't sue my a$$ butt 8oz in 1 gallon, a little Amsoil 2 stroke oil, maybe some Amsoil PI, and a dropper or three of Amsoil fuel stabilizer (don't laugh - the stuff works great under boost in my turbo)
Some octane boost formulas contain nitropropane, an o2 carrier.
If the hole in the piston was caused by a lean condition, the octane boost could make the hole bigger, faster.
Be careful with those av gsolines, they have a rich/lean dual octane rating.
Through just a little Amsoil 2-cycle oil in there along with Outlaw octane booster. Userfriendly has a good point, check the mixture.
I don't know where you're located but around here, a lot of the guys run VP Racing fuels. They have a whole line of unleaded racing fuels with varied octane ratings. I'd steer clear of anything with lead. You engine is modern and was designed for unleaded. All you'll be doing with leaded fuel is watching your spark plug life go down...

[ October 23, 2003, 03:55 PM: Message edited by: jsharp ]
The Kawasaki Mojave is a 4 stroke, so what is all the talk about 2 cycle oil. The gas and oil in that engine should never have anything to do with one another?
Are you sure the race gas is leaded? Unleaded, oxygenated 108 octane race gasoline is the one most commonly available in California. A major oil company, 76, even markets it. Apple Valley is not Los Angeles, but you should still be able to find a distributor in your area.

Leaded aviation gasoline and PAO oil did have a serious problem, but that fuel has a lot of lead in it and aviation oils are almost pure base oil minimal additives.
It would be a good idea to take an elastomeric O-ring and drop it in a jar of whatever nasty hydrocarbon you plan to use as an octane boost, to see how it does after a few weeks. Specifically, I'd look for volume changes and crosslinking of the polymer, which will cause the O-ring to lose its' elasticity. All elastomers are not compatable with all hydrocarbon fluids ....

Ignorance is often bliss, but I wouldn't bank on that!

Too, if you're addressing the use of toluene--often misspelled tolulene, BTW--in gasoline, it's already used in all (as I understand it) modern gasolines. I'm not worried about adding a little more.

And I certainly hope my blissful ignorance does NOT prove to be undeserved.

BTW, this toluene smells JUST like the 91AKI gasoline I buy!
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