calling all sled experts

[2g00d4u]

So I got this 1975 ski doo TNT everest 440, should I be running leaded gas in it or just straight gas? (with oil of course) I was told to by the previous owner and got a bottle of Formula 1 lead substitute for gas, but I've learned not to trust the opinion of a previous owner. and all the vintage sled forums I could find say nothing about leaded gas, just a 32:1 mix of gas/oil which I will do anyway.

simplest question: Should I use leaded gas or no? whats the difference from straight gas/oil mix?

thanks for any help. I:I

 

[motoman9911]

You really don't know the difference between straight gas and "oil mix?" "Oil mix" is premix, which has oil already in the gas. You have a Blaster, you should know this.

You should not need lead additive with a 1975 model. I thought that lead sh*t was gotten rid of in the 60's or something? Someone want to confirm? I wasn't alive then and don't want to research it.

 

[2g00d4u]

when did I say I didn't know the difference?

the question is do I add lead substitute or not.

 

[Awk08]

i can remember "regular leaded gas" still being available when i was 16, way the hell back in 1979, and for .75 cents a gallon to boot,
and having to scratch off the "unleaded only" sticker on the gas cap with my key, so the "station attendant" would fill me up with the cheaper regular leaded gas, he seriously wasn't gonna do it because of that sticker on my 75 impala, so it had to go, hahahaaaa

and the theory was that the lead lubricated the valve train,
which a 2 stroke doesn't have,
so you'll be fine with some good 'ol 93 sunoco mixed 32:1

and that was a sketchy read on the "premix question" and an easy misunderstanding, i think it was missing a coma ,,,,,, somewhere

 

[Braaaptor]

No, you don't need to use any lead additives in a vintage 2-stroke. The lead in gasoline back in the day was primarily used to help lubricate the poppet valves and seats in 4-stroke engines.

In short, vintage 4-strokes did not have hardened valve seats from the factory, and so without a lead additive, problems with burned valve seats or sticking valves may arise. People who, to this day still run their old 1940's Allis-Chamlers, Farmall, Case, and Deere tractors on modern gas with no valve problems would probably argue otherwise, but ag engines hardly qualify as "high-performance". Most just chug along happily, putting out maybe 35-50hp @ 2,000 RPM.

Bottom line is, since there are obviously no mechanical valves in MOST 2-strokes, as long as you use a quality pre-mix or injector oil (whichever your sled requires), you will be fine. No lead needed.

Yeah, reeds qualify as a valve, I know, but they work off crankcase vacuum. Rotary intake valves are another story, but since they aren't subjected to high temps/pressure, they shouldn't be affected by a lack of lead. Not familiar with sleds, but I'm sure most use the standard reed induction system, rather than rotary valves.

 

[2g00d4u]

thanks guys. I have XP Pro 2 stroke oil or something to that effect, there is no injector.

 

[Braaaptor]

Then go ahead and mix and ride! Have fun! Like on a Blasty, I'd mix it 32:1. Some older 2 strokes recommend a richer ratio, but pre-mix oils are lightyears better than they were back then. You don't need to use as much oil per gallon now that its 2011.

Oh, just don't use oil engineered for outboard boat motors. Be sure its rated for powersports engines.

 

[2g00d4u]

gotta bring this back for a sec.

I was told the lead additive I was given for my sled was not for lubrication, it was to help the engine run cooler. Can I still run it without the lead additive and not be running hot because I have a good quality 2 stroke oil? for that matter, does the lead additive even make a difference in running temperature?

thanks again you guys.

 

[2stroke4ever]

the extra heat would be coming from friction, not the burn of the fuel, someone planted this leaded gas idea in the previous owners head, forget he ever said anything about it, mix er' up and ride, comparing 2 stroke oil's lubrication to leaded gases' is kinda apple's and oranges but ya your 2 stroke oil will do that motor just fine

 

[2g00d4u]

alright just had to be sure. rep given to you all.