New to dirt biking, questions regarding oil mixture for a MX250

[inotocracy]

New to dirt biking, questions regarding oil mixture for a YZ250

Hey guys,

I recently picked up an older 88 Yamaha YZ250, it runs great and looks clean! One question I have that I never bothered to ask the original owner is how much oil should I mix in when I fill the gas tank? What kind of oil should I be using (10/30?), is there a special oil made for dirt bikes? I assume that I should be using 92 octane gasoline too?

The last dirt bike I had was a tiny little 80cc when I was a kid (10 years ago) so I have no clue as to what the proper ratio of oil/gas is. Also, any maintenance tips you guys could give me? Anything I should be checking/changing on the regular?

Thanks in advance! I cant wait to take it to Carnagy this weekend! :laugh:

edit: wow embarassing, its a yz250 :bang:

 

[robbieisurfriend]

You should go buy some decent 2 stroke premix from your local shop or online. I suggest a good synthetic like Klotz or Bel-Ray. With a cheap oil I would mix at 32:1 or greater or with a good synthetic at 40:1. It all depends on your jetting. Any premium pump gas will work fine. Just stay away from regular. Usually you would ask these questions to the person you bought it from.
As far as maintanence goes, I would change all of the fluids before even riding it. Then change your oil after every couple of rides. I use type F Automatic Transmission Fluid but you can use anything from 10w40 to 80wt gear oil in a 2 stroke.

For future reference, use the search button before you ask a question. There are about 5 of these posts a week atleast, all of which could have been done without. Most people wouldn't have even answered your questions. . .

Welcome to the forums, and dirt biking.

 

[inotocracy]

Thank you! I did try searching but the topics that came back weren't specific to my bike (wasn't sure if it should be or not). Just one last question.. should the oil be dumped in the dirt bike's tank with the gas or should I put the oil in the gas canister and shake it up? Forgive my ignorance on the topic :(

I used an online calculator and for every gallon of gas I should be using 4 ounces of oil if I do 32:1, and 3.2oz for every gallon if I do 40:1 with synthetic. Does that sound about right?

 

[robbieisurfriend]

Thank you! I did try searching but the topics that came back weren't specific to my bike (wasn't sure if it should be or not). Just one last question.. should the oil be dumped in the dirt bike's tank with the gas or should I put the oil in the gas canister and shake it up? Forgive my ignorance on the topic :(

I used an online calculator and for every gallon of gas I should be using 4 ounces of oil if I do 32:1, and 3.2oz for every gallon if I do 40:1 with synthetic. Does that sound about right?

Yes that sounds right. I suggest filling a 5 gallon can with 4 gal and adding your premix to it. You could mix a tank at a time, but why. . . More room for error.
I honestly have no idea what a MX250 is but most 2 strokes run about the same mixture. Most bikes call for 32:1 from the factory from what I have seen. You could in theory run one at 70:1 or better if you had it jetted correctly.

 

[inotocracy]

I'll give 40:1 a shot with a synthetic like you recommended. I'll take a trip over to cycle gear later today and see if they have what you mentioned, and also pick up a 5 gallon can while I'm there. Thanks again for the tips! If anyone with my particular bike, or anything similar, wants to chime in with anything please do!

edit: trying to find the manual for this bike online but not having any luck. Anyone have a link to a similar manual, or even a link to a maintenance guide?

edit #2: found a maintenance book for my particular bike, seems to be a good one!