Very interesting. I posted this in another pre-mix thread:

I did some calculations on the oil consumption rate and gas mileage for my S5 n/a. Based on those numbers, the stock OMP is metering out oil at about an average rate of 1/2oz of oil per gallon of gas burned or 1:256 ratio overall. Now on long highway trips that rate drops to 1:400 ratio and raises to as high as 1:128 or more at track day events.

So if I were to start to premix just as an insurance measure, I would most likely do it at a rate of say 1/4oz per gallon. That would be a 50% increase (on average) compared to what the S5 OMP is already doing. If I were to premix at 1/2oz per gallon that would be double what the OMP is currently doing (again on average) - which maybe what I would do for track day events.

I just rebuilt the engine in my moms weed eater...I know it isn't a wankel, but it still applies.

When I first fired it up, guess what was slowly dribbling out of the exhaust port? Somewhat burned but still slippery 2 stroke oil. :)

I had the muffler off, to test the rebuild before I put everything back together and yes, not all of the oil was cooked off during combustion. This supports a previous posters point that not all of the oil is burned off. It wasn't much, but something so that tells me, the oil will SHOULD keep the combustion chamber lubricated if you have no OMP.

I know it's apples and oranges type of thing, but it can't be that different.

EDIT: Beer, not Vodka

you stated in your first post; gasoline is volatile. oil is not. since the oil separates and is non volatile, couldn't see it burning off completely.

kind of in the same token here, on the topic of fuel cut on decel and lubrication with no omp, i would think without combustion occurring that less lube would be necessary. really just assuming though. also, since, as previously stated, we've found that the premix hangs around, that should be adequate

I really think I need to start pre-mixing, the original owner used nothing but Mobil1 full synthetic... sigh
Bye bye money!!!!

I have a motor that just recently went south being rebuilt tomorrow that runs only premix no omp I will post the damaged housing and the good housing for comparison sake. I will be running no OMP again :) I premix 1 oz of 2 stroke oil to 1 gallon of gas.

cool, I have been wanting to see a premix run housing.

For people asking how to measure: I just wait until I get home and then pour it in a measuring cup, then into the gas tank. Simple and better than keeping an oily bottle in my car lol.

The only issue with that is, some of the oil you pour in stays sitting in the filler neck. Not that it's a huge issue, just pointing it out.

as promised it is a day late sorry for that. but here are the pics of the good and bad housings
Bad Rear Rotor Housing
Attachment 651322
Attachment 651323
Good Front Housing
Attachment 651324
Attachment 651325

it might be better, but i would hardly call it "good". :)

its very usable still within specs no groves or anything

..

Been away for a good while and back to find this thread. Original GXL owner here, never premixed but also never used synthetics. Now sold on the premix, emissions not withstanding, and regret not learning earlier.
Thanks! (and now back to the pre-mix FAQ)

Ha! I was looking up housing wear pictures on google and stumbled back to my own thread here.

I read through it again, and I'll add this since I keep seeing incorrect numbers being posted.

There is 128 ounces in a US Gallon. So adding one ounce of premix per gallon of gas is 128:1 ratio, not 100:1 people have claimed...it's basic math.