2 stroke oil question

If you can avoid mixing the old with the new premix, that would decrease the likelihood for problems.

That being said, the likelihood for a problem in mixing the old premix using Motorex with any new premix using a JASO FD, or ISO L-EGD rated oil is pretty slim.

Lots of brands carry those ratings, so see what's readily available to you and go for it. If you have the patience to look through spec sheets, try to narrow your selection down to something similar in viscosity and flash point to the Motorex product you were using. That will at least get you in the same ballpark with regard to physical properties and solvent content.

I rum Amsoil Dominator in my bike and like it a lot. I had 90 hours on my stock top end with very little wear. You can mix it since its only a half tank, I don't see that hurting anything and I've done it myself.

I've never been a fan of Motorex. KTM used to dump out their oils and refill the bottles so people saw them using it in the race bikes when it was really rotella.

I personally don't like to mix oil. Half a tank of gas? I dunno... dump it in your truck? It's probably race gas, though, right? So there's a $20 bill in that 1/2 tank, basically? What I guess I'd do is mix up fresh whatever and then go riding for a bit. Once I've ridden it down to 1/4 tank or less, then I'd add the new stuff.

As far as the oil itself goes... I don't think it's going to matter all that much. I've used Maxima Super M, Maxima K2, Lucas 2-stroke, Yamalube, Kawilube, Klotz in 3 different variets, and I'm using Motorex Cross 2T now. All at 32:1 in a 125 or 40:1 in the 150's. We tried 50:1 and didn't like it... didn't burn off as well (more fuel = cooler burn).

You gotta consider how hard you ride and pick a flash point that more or less matches. Klotz didn't do well for us- lots of plug fouling and spooge in our enduro KTM's. Lucas has a low flash-point and works fine in an off-road bike (I use it in the Gas Gas TXT) but I didn't feel good about it in the 125. Yamalube and Maxima Super M both spooged a lot. K2 was good but expensive. Motorex Cross 2T seems just right.

I'd just just mix up 5 gallons of whatever and go back to Motorex when you can. But this is an oil thread so who really knows?

As long as same type oil you shouldn't have an issue. I've switched synthetic to synthetic many times with no issues between HP2 & Maxima K2. And I am picky as heck about fuel stuff. As for actual brand -any quality synthetic oil will work fine.......

What do you have access to?
Are you shopping online or at the dealer?

Belray is the Husqvarna equivalent of Motorex and most bike shops have H1-R as their top esther synthetic premix oil. I would say that choosing the right oil is critical on highly tuned small-bore 2-strokes and less so on 250cc + bikes.

I would never throw away good premix, unless it was getting too old. Mixing brands has never been a problem or a concern for me.

I used Maxima SuperM, Supertech, Bombardier and Honda HP2 at 60:1 to 50:1 on my 2017 250SX. For me, it's like putting logs on a fire. We all have a favorite, but when it's cold, you'll throw on whatever works.

Any of the OEM snowmobile oil is good too. Those motors get absolutely thrashed.