Oil mix


Can you guy's give me some pointers as to the recommended mix for the YZ 250? I have just got a 2001 and this is my first 2 stroke bike. I have never had to worry about mixing fuel before as I have only ever owned 4 stroke bikes.
The manual say's to mix 30:1 but a buddy of mine said to mix 25:1 and someone else has told me it should run on 40:1.
I am really confused and thought maybe you guy's who actually ride them would be able to tell me better.
Cheers in advance


Some say to do what the manufacturer says and some say to do what the oil company suggests. To make it simple, use a good oil like Yamalube (I use Bel-Ray H1R in my RM250) at 32:1 or whatever the race team uses. That amount of oil (30 or 32) in the mix gives the most lubrication. Some oils can be mixed at 40:1 in your bike like Golden Spectro (I've heard nothing but good from this oil). If you ride slowly, at low revs you can factor that in and run it richer (less oil). However, if you race and are keeping it pinned all the time it is best to use more oil (leaner) for more protection. Chances are anything near 30:1 or 40:1 will be fine on a 250. But either way, you should jet the bike (starting with calibrating your float bowl height) for mixture ratio you decide on because the premix ratio affects jetting. Good luck!


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Depending on how scientific you want to be, it depends on a lot of factors.  My old 84 Cr250 (back in the day) called for 20:1.  I used to fould plugs like mad.  I switched to 32:1 and it greatly improved.  That was at sea level.

Fast forward to now and I have a 500 2-stroke and reside and ride around 5,000 to 7,000+ feet above sea level.  I run 44:1 now and she runs like a champ - never had a spark plug problem, no overheating, very minimal spooge.

Do a search on oil ratio and I'm sure you find good stuff.  If you see Mr. Rorich's techy posts, wait until your head stops spinning before you decide to sell your 2-stroke. :eek:
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Who me?
I have run every 2 stroke (motorcycles, weed wacker & chain saw) I have ever owned at 40:1 with various oils and have never had a problem.


I use golden spectro at 50:1 and it works good. The 20:1 and 32:1 ratios were based on the old castor oils, whereas the newer syntec and syntec mixes like golden spectro are concentrate oils that can be safely mix at 50:1 ratios. Anyways, good luck with the bike.


Cheers Guy's
I went out yesterday and ran it on 40:1. It does smoke a little, which is something I am still not used too having only had 4 strokes before. I love the bike, it is a mixture of joy and fear to ride :)
I may experiment over the coming weekes to see how I get on with different mixtures, but I think 40:1 will be the norm.
Thanks again for your time
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