I just built a 70cc 2 stroke zip. I had a stock airbox with normal sponge in, 72 main jet, leovince zx exhaust. Was running good n shit then after i took it for a ride after like 2 days it just died. I took it home, next day i checked all i see that spark plug is totally full of oil/fuel. Then I changed spark, working good left it idle but then i saw it was spitting drops of oil from exhaust. I put main jet 70, still same airbox, air screw 3 half turn/4 half turns. Ran it, was working alright on idle then after few mins it started spitting oil again..... Why does it do that? Any idea? Idk if i should put any lower main jet cus everyone I know has 72-78 jets on their 70cc and everyone told me to put at least 72....... Anyone know? Thanks
Plug was also black and oily thats why i set the jet to 70 for now looks ok but im not riding it cus of oil dripping from exhaust (black oil), i use premix 1:33.
You want to run the bike on the biggest jet it runs smoothly with as it’s safer. I’d say that’s a little to much oil, What oil are you using ?
zea but when i had jet 72 spark plug was covered with oil. u think mixture is bad_ what u suggest me to do_
Ok good, I’d run that at 40:1 for a few miles then check the plug again. But like I said if there’s no difference in the ride with 70-72 jet I’d put the 72 back init
Yeah ok. the high end race kits only just call for a 33:1 mix so I’d hazard a guess that it’s just to much oil. Use fully syinthetic if your not already