Re: Opti-2 Great stuff!
I used to be of the mind that any engine should be broken in on dino oil before switching to synthetic, but for awhile now I just run what I a going to run right from the start.
I build up my own racing GX200 clone kart engines turning up near 7000 rpm and have found no advantage to breaking my engines in on dino oil. I run Amsoil 5w 20w synthetic right from the first start and my engines have more hours and more hard laps then most I race with. I run with an oil catch can on my kart and the catch can is always empty which tells me that I have good ring seal and very little blow by.
I also convert Ryobi weedeater engines into radio control aircraft engines and have used many purpose built Zenoah aircraft engines. I used to be a firm believer that nothing but Lawn Boy ashless 2 stroke oil mixed 32:1 should be run through my engines, and using a 100:1 mix was insane. However after watching others aircraft engine after engine running 100:1 Amsoil with great results....I switched to 100:1 and my engines couldn't have been happier. After a few tear downs just to see how the engine was affected....I was happy to find my engines really clean with little signs of wear or over heating running 100:1.
So..when it came to trying Opti-2 mixed 100:1 in my 66cc "HappyTime" ....I was not surprised to see it performs well. I started my newest build using Opti-2 100:1 the very first start. The engine is breaking in nicely and I expect the engine to do well and be quite happy running this mix.
I am still a fan of Castor for some applications and some of the dino oils are just fine , but with some of the great full synthetics and partial synthetics there really is no reason to have an engine covered in messy castor inside and out or to have to put up with a smoking 2 stroke engine when 100:1 Opti-2 will eliminate both those issues. These are my own experiences with using 100:1.