I started out running Amsoil Terminator (full synthetic), a very good oil, but then got hard to find at a good price. So I looked around and got some good deals on snowmobile oil (full synthetic), as I recall I bought 2 different gallons of the stuff. I don't remember brands, but no problems, no smoke, worked great.
After that, I didn't see any more good deals on snowmobile oil, so I decided to try some semi-synthetic. I figured, just street riding, I was wasting my $'s on expensive full synthetic. I looked around and decided on Lucas Semi-Synthetic, had good reviews, and very good price. I bought a gallon and started using it. Weather was warmer and was working OK for me, so I bought another gallon.
I think it's a pretty good oil in hot weather, but cooler weather it was giving me trouble. 1st it smokes, not just a little, but a lot. Next, with the LC engine, I think it takes awhile to warm up, and 1st couple of red lights after idling awhile, it became a mosquito fogger, and ran bad until it cleared out after the light turned green. I even think it was messing up my carb tuning, plus was fouling plugs fast.
So, I started looking for another full synthetic and after a lot of research I settled on Lucas Snowmobile Oil (full synthetic), another snowmobile oil. The other choice was Bel-Ray Si-7 full synthetic, but Lucas Snowmobile was less $'s so I tried it. I also looked hard at Royal Purple Full Synthetic, but was pre-mix only, not recommended for oil injection systems. Funny thing, I read that Royal Purple makes the full synthetic snowmobile oil for Lucas. You have to look at the Lucas website, but the Lucas Snowmobile oil is recommended
for premix and oil injection.
If the Lucas Snowmobile gives me trouble, I am going to Bel-Ray Si-7 next. So far, it's like night and day, no more smoking, idles better, no more loading up at red lights. When weather turns hot I will try to run the Lucas Semi-Synthetic again, but for cool weather I don't like it.
Cheers