Oil ratios and types

[gasser]

Don't get hung up on what the factory recommends for fuel/oil mix ratios - they don't know which oil you're using. They do know however that most dino oils are not made to work well beyond a ratio of 40/1 and most synthetic oils aren't made to work well at ratios above 50/1 so they probably jet the carbs for a 40/1 ratio. Yamalube 2T is a great oil mixed at 36/1 but do not run it at 50/1. Amsoil Dominator is a great oil mixed at 50/1 but do not run it at 80/1. Always mix any oil you use at the ratio recommended by the oil manufacturer. You can decrease the ratio (more oil to gas) with no ill effects and you will pick up more power because the rings will seal better. That's why a lot of racers will use 36/1, 32/1 or lower.
Now to help you out - If you want to squeeze every bit of power out of your 300 then mix a good dino oil or synthetic mix at 32 or 36 to 1 (kawasaki racing, Yamalube 2T, and Klotz are some that I like). Be sure to rejet your carb if you use the lower oil mix ratios because adding more oil will result in less gas being mixed with the air in your carb therefore leaning it out and making the bike run hotter - maybe too hot. If you want to run 40 or 50 to 1 any of the better synthetic oils should give you just as good wear protection as those same oils would give your engine when mixed at 32/1 but not as much power. The advantage to running less oil is less smoke, less pollution, a cleaner engine, and a cleaner silencer. Personally after trying all the good synthetics I settled on Amsoil Saber(100/1). It is noticeably cleaner than the others and offers full wear protection up to 80/1 under racing conditions and 100/1 under normal conditions. I run 64/1 which is 2 ounces per U.S. gallon. My reasons for switching from 43/1 to 64/1 was to save money, reduce cleanings of the power valve and silencer, and smoke less than the other 2 strokes. Changing my mix ratio that much did cause jetting to be a little rich.

[stay_upright]

I found that running clean has more to do with how well the bike is jetted at low throttle openings than the oil ratio.

If the bike does not pull cleanly from low throttle openings i.e. just off idle then it is 4 stroking and every other cycle is a misfire which deposits plenty of oil all down and out the exhaust, particularly when you accelerate this all comes out as smoke and spooge.

I'd also be nervous at running 100:1 the protection oil provides depends on the thickness of the oil layer between the metal bits it is trying to seperate, which is dependant on the quantity of oil between the surfaces among other things, some-one on here has already proved scientifically that using more that 50:1 reduces wear significantly so I'll be following his findings and richening up my 50:1 but with a clean jetted bike I should have nothing but a small waft of smoke out the exhaust.

[iancp5]

I think the quantity and thickness of oil on friction surfaces is more than just the ratio. It'll depend on how well the oil is sticking and sticking together. I run Putoline MX7 at 50:1 and when I do a strip down I'm always surprised how much oil is clinging to everything but very little carbon on the crown or head. I only wish that Amsoil was easier to get over here because I'd love to try running even less oil.

[firffighter]

What do you all think about running Motorex?

I have a local KTM dealer nearby who is about the only shop open since 2 others have gone out of business lately, and they sell Motorex exclusively.

[skid jackson]

motorex is a swiss company
The swiss are usually pretty good at whatever they do .....
not that that is a good way to pick 2t oil ..... but ....
I certainly would not be afraid to give it a try.
I bet its pretty good stuff .....
Never used it though

[gasgasman]

That's all I use, Motorex full synthetic.

[geraldh]

I've herd of guys that have been running full synthetic CHAIN SAW oil in there bikes for years with no problems.... I gues that as long as the ratio is right it should work... Do you guys think there can be that much difference as far as aditives go. Now that I am thinking about it dont Chain Saws run to 18000 rpm or somthing like that.

[iancp5]

Originally Posted by gasgasman

That's all I use, Motorex full synthetic.

Used the 4T oil. No problems. Never heard of anyone having a problem either.

[Skidad]

Originally Posted by geraldh

I've herd of guys that have been running full synthetic CHAIN SAW oil in there bikes for years with no problems.... I gues that as long as the ratio is right it should work... Do you guys think there can be that much difference as far as aditives go. Now that I am thinking about it dont Chain Saws run to 18000 rpm or somthing like that.

You're probably thinking of the Opti-2 oil. Actually very good stuff and no kidding can be mixed at 100-1. There are a bunch of people on KTM Talk who use this oil. Some run it at 75 or 80-1 ratio because it makes them feel more comfortable but it can be used at the 100-1 ratio. Pick it up at many lawn and garden shops. I would consider trying this oil.

http://www.opti2-4.com/html/opti-2.html

[tprnottp]

In the past, I ran Mobil MX2T at anywhere from 32:1 to 40:1, depending on riding conditions. After finding it hard to get my hands on MX2T, I switched to AmsOil Dominator and have used at the same ratios. Again, both oils have performed well. (Some smoke/no spooge, but then again, I know I'm running a bit heavy on the oil for added protection.)

However, I'm now considering switching over to Opti-2 since, by all accounts, it seems to run clean and provide an inexpensive alternative to Amsoil Dominator (will use less oil?)--which I now have a problem getting.

Question: Since the Opti-2 web site recommends mixing on packet (1.8ozs.) of their oil with one gallon of gas, a sort of "one size fits all" mixture for every two-stroke application under the sun, should I consider re-jetting to be on the safe side?

For me, I'm a bit apprehensive when it comes to running mix ratios at 80-plus to one.

Thanks for your advice,

TP