Synthetic oil and petroleum based oil

[robertnj63]

Hi, I have searched this forum and found many topics that pertain to this but i cant find an actual answer. Maybe somebody can help. I have 2 2009 tomos moped with about 300 miles on them. They have a small oil tank for oil injection and currently are filled with Belray S2 2 stroke oil. I would like to switch over to Belray Si-7 synthetic oil. Can i simply just start adding this oil to the oil resevoir even with the other oil in there? I really would hate to have to go to the process of trying to drain out the oil tank. I emailed Belray and have yet to get an answer. Any thoughts would be appreciated. Thank you

 

[Bluestream]

I would run the tank as low as you are comfortable with, then top up with the new oil

 

[boraticus]

You're OK to go from conventional two cycle oil to synthetic oil. Some oil manufacturers actually make conventional/synthetic blends. Why do you want to switch to synthetic? I doubt that you will notice any difference other than how much you spend on oil.

Being such a small engine, with minimal consumption, I guess cost is not an issue. I buy two cycle oil by the gallon. To me, cost vs. benefits just isn't worth the difference in price.

 

[robertnj63]

I want to switch just for the added protection. These mopeds run at full throttle in hot weather for hours at a time. The synthetic has a slightly better rating. As you said, the use is minimal so cost really isnt a factor. I just read so many conflicting reports about mixing synthetic with regular 2 stroke oil, such as the oil will gel, etc.!!! I would hate to remove the oil tank to drain it as the little hose fittings dont seem like they would seal as tight once i remove the ferrules. I was hoping to just pour it in when the regular oil starts to get low.....

 

[boraticus]

If you're that concerned about the mixing, take equal amounts of what you're using now and the new synthetic, put them in a clear glass container and mix them up. Let it sit for a couple days to see what happens. I suspect that they mixture will stay mixed. If it does separate, so what? Whichever is on the bottom of the mix will be used by the engine first. It's all still oil.

 

[robertnj63]

That makes complete sense, just figured there had to be someone in this forum board that was in the same situation as me!!!LOL wanting to add synthetic oil to dyno oil in a tstroke motor. I think im just going to pour it in. Thank you for the great idea about testing it.