Opti 2 Issue - bad bogging at full throttle

[RB55]

Hi,
66cc Chinagirl engine has about 170 miles on it, has been well broken in. Decided to try Opti 2 @100:1 today, as suggested by many in this forum. As soon as I switched, the idle drastically decreased (idled far too low, had to increase) and now it bogs badly most of the time at full throttle. I read that this is because the fuel/air mixture is richer with a smaller content of oil. Is this correct, and if so, could I just run the Opti 2 at 24:1 like I do with my regular oil? Thanks!

 

[GreasyChris]

I run redline synthetic oil at 32:1 and I've got over 2000 hard miles on that engine and it still pulls strong. You most like need to adjust your carb for that oil mix ratio

 

[Frogslayer]

You can run more oil to help your fuel air ratio but it kind if defeats the purpose of the opti mix

 

[gary55]

I error toward the side of longevity so suggest 32;1, but have heard many have good luck with the Opti at 40;1. 100;1 in these engines is just not a good idea.

 

[RB55]

Update to all - switched to 30:1 standard oil mix and bogging is gone. Used standard STP 2 stroke oil. Interesting to see how much oil can affect the air/fuel ratio; it’s like a different bike now! I will be trying 30:1 Opti 2 after I get through this gallon of gas and post the results here.

 

[Street Ryderz]

Update to all - switched to 30:1 standard oil mix and bogging is gone. Used standard STP 2 stroke oil. Interesting to see how much oil can affect the air/fuel ratio; it’s like a different bike now! I will be trying 30:1 Opti 2 after I get through this gallon of gas and post the results here.

32:1 is a standerd mix ratio rather than 30:1 and 32-40:1 is safe with good oil and not a crazy high performance rig.When single speed,single cylinder 2t's are used in high rpm high load conditions like a kart engine the mix is 16:1 and guys running scooters use 17-20:1 as normal running mix. 40 and 50:1 are around 2% of oil by volume and where the oil does alot of the cooling along with stopping the moving parts from shredding them self's it's probably better to have to much rather than to little right.

 

[FNTPuck]

Everyone has their own opinions on oil but if you are running a newer sleeved chinagirl keep it at least 32:1 to prevent soft seizing or damaging the piston skirt - especially if its a steel sleeve instead of iron. For standard chrome jugs I like 40:1 of a quality synthetic, and recommend 32:1 if its using cheap stuff. They only run "better" with heavy oil when stock because they are very rich from the factory and that leans it out.

I would never run 100:1 in a chinagirl, I don't care what exotic expensive magical oil it is . Its not a nikasil coated chainsaw, its a super thin chrome layer on crappy chinese aluminum...heat and friction will kill it FAST.

 

[IcePS]

I would just play with the notches on the main jet until most of the bogging goes away. (Be careful not to jet too lean)