sandmanmike1
New member
What is the mix ratio for a 78 yamaha et 250. The tank has a messed up cap so I am eliminating the primer switch on the dash and oil tank and doing pre-mix with a gas tank from a yamaha blaster. Should fit nicely under the hood.
I would guess like 20:1. More oil wont hurt. I looked at a YamaLube can and it might either be 16:1 or 24:1.
then I would lean that out and check plugs....
sandmanmike1
New member
Thanks for the info. My son was pretty excited to here her run. I bought it off a co-worker for $150 who said it just stopped one day. Put a 17 dollar coil on it, pulled it 7 times and it fired up. Needs work but with the help of TY It will be good too go.
Awesome 
Keep us posted.
Keep us posted.Oleyamirider
New member
- Joined
- Jan 1, 2025
- Messages
- 4
we have a had a 78 ET 250 since 84. i run Av gas 20-1.. only reason i use AV gas is it doesnt get used every yr and AV gas lasts waaaay longer than the chit ethenol gas we have now. it wasnt used 4 yrs and new yrs eve it started in 3 pulls.my son repainted it 4 yrs ago.and i redecaled it..a friend that has 4 of em rebuilt the seat and i just got a new windshield for it..also put ski skins and ice scratchers on today with the no snow we have,, going to Edsons Antique ride in 2 weeks,and our poker ralley if its not cancelled like the last 3 yrs.
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Nice!!
BornYamaha
Member
To anyone, Do not, I repeat, Do not use yamalube R for snowmobile premix if you are out riding and need to do the old gas station fill it up, put the gas in then shake the sled to mix it. I did this one time when it was about 15*F. All the oil went to bottom of the tank in a big thick glob then got sucked into the carb with nearly no gas in the mix. It went about a 1/4 mile out on to the lake then stalled with the all oil mix. Had to be towed back. The yamalube R is just too thick. Not sure about regular yamalube. Never tried it. If the non-synthetic even still exists. I have beed using Polaris pre-mix oil made specificly for old sleds at 32 to 1. Been working great.
Have always used 2R for the dirt bike and 2S for the sleds. 2S hasn't had any issues in the 340 Enticer with the injection removed.
BornYamaha
Member
I always used 2R in my dirt bikes too and road them in the cold. Not saying the oil is bad. Maybe the 2S is fine. Never tried that. If it is properly premixed in a can or where the oil starts out warmer it may it stay mixed just fine. I am just telling you from personal experience that if you are out riding at about 10* and need to fill up at a gas station, fill it up with gas then dump in the oil it will go straight to the bottom of the gas tank like a big blob. It does not want to mix with the gas at that temperature no matter how much you shake the little sled. I hate mixing that way but if you are out away from home and need gas it becomes a necessity. I saw many people do this when I was young on their old premix sleds with no problem. I never liked the idea of it but that's what they had to do. I rode a Yamaha then so I had injection and didn't need to worry about it.