500 Two stroke gas/oil mixtures

[DenverSnowBike]

What's everyone using running the 500 smokers?

Anyone using high octane or just pump gas?

What oil?

Engine mods?

32:1?
40:1?

 

[M5-]

I've been running mine pretty rich oil wise. Usually right around 30:1 at the most, it is a 25 year old motor designed some 30+ years ago. There isn't any real harm and there are some benefits like better ring seal and better bearing oiling. People believe you will foul plugs but that's a jetting problem not the oil mix.

M5

 

[portgrinder]

30:1

C12 equivalent. got a fair amt of engine work

 

[needpowder]

40:1
4 gallons 91. 1 gallon 110. 16 oz motul 800.
Probably don't need the race gas, but it smells good.

 

[SEOINAGE]

32:1
91 octane, although I might have to get my hands on a bunch of avgas as it stores better than pump gas, and is well worth running.

 

[DenverSnowBike]

32:1
91 octane, although I might have to get my hands on a bunch of avgas as it stores better than pump gas, and is well worth running.

That's what I was thinking too. Even in my 450 I get a 101/91 blend (makes it like 94) of non ethanol. I just like to run clean, stable gas.

I want to do something similar for the KX5, maybe just run a straight 101 or av gas or something....

 

[summitboy]

Depends on the state of tune of the 500 motor. If its stock i would run nothing but a good quality Shell 91 at 32:1. Any mods what soever id run some race fuel such a C111/C12 at no less than 50/50. When the 500's get hot up the trail they can become susceptible to detonation. Really comes down to how the motor was ported and modded etc. I'm not a fan of Avgas for the simple fact it wasn't developed to run at high rpm, rather a low rpm constant throttle situation such as air cooled Cessnas ! Lots of people run it though in mod sleds etc. Pick your poison ! I know some are lucky enough to have race fuel at the pump in places like MT which is what i would run straight if we had the option here !

 

[CATSLEDMAN1]

WHAT TO RUN

times have changed the compostion of the 2 stroke oils a lot in the last 15 years or so.

first, its the additives in the oil that provide lubricartion for your bearings and rings not the greasy vehicle you feel on your fingers, more additives is good, more grease is not good. all the high quality 2 stroke oils with correct rating have far more and far better addatives than were avialable 10 years ago. MEANING: 50 or 60 to one will do a better job today than 32 to one 15 years ago.

do the research, more oil body does no provide more ring seal, oldest old wives tale in motorcyling, that was a yamaha thing in the 70's. been proven on hi perf sled engines that this does not work or help, just smokes alot and builds carbon.

sad part is gas has gotten way worse, deto all over the place on old 2 stroke hi perf engines with old world porting and pipes, buy some good gas and run rich, more oil will equal more deto.........bad news.

 

[rhino89523]

My bone stock trail bike gets 40-1 Super M on 91 pump gas with a stock PJ carb, stock pipe, stock ignition and gets jetted right out of the book. I run it at my house from 5000ft to 9000ft on the first pull out of the garage. I run it in Colorado up to 12,000 ft and in California at near sea level. I run Arizona every year where it's hot, and the temps range from 0-100 at my house near Reno NV all on Book jetting. She runs perfect, 97 motor in a 250x frame.

My sand bike is a steel framed bike with a 1991 bottom end (close ratio) ported with Bridge removed, squish modded, bottom end ported, PWK carb, FMF Fatty pipe, no spark arrestor unless caught, CR250 ignition, high compression motor. I still run the same oil at the same ratio but that bike needs some more octane. I go 50/50 pump/ race gas. I could probably get by with less race gas but I love the smell and how crispy it runs on the stuff.

Both bikes get all gas dumped out of them and floats drained off if I am not going to use them for more than a couple weeks. The sand bike I only run a few times a year so it gets drained basically every time. The trail bike never needs it I pretty much ride it weekly, sometimes I'll get carried away for a month or so riding just my 650r and then I will drain it.

This year coming up will be my first year with a snowbike. I had enough pieces and motors around to build up a dedicated CR500 for snow. I'll probably just do the same thing I have been doing with every other CR500 I have been riding. Started riding them in 1988....never been on anything that makes me smile the same....well maybe the xr650r...but its different.