Hi All, 

I'm a 2-stroke novice here but I have been working on bikes for a while and I'm just curious to know what the difference between all the different oil types is. 2-stroke oil, SAE, Fork Oil etc. Are they ever interchangeable and what sort of problems could it cause if you use one over the other?

Thanks,
Jess

Don't over think this. Best to use the proper oils in there proper applications. Although you can use SAE motor oil in older Yamaha forks instead of fork oil and sometimes works better.

In the transmissions you can use different types of lubricates as well but i always stay with Yamaha's Trans-oil plus gear oil 20w-40 for 2 stroke gear box/ transmissions. Works extremely well with these old wet clutches.

Wet clutches in old two strokes don't like the newer oils with anti-friction additives in the transmission. Makes them slip. I also use YamaLube 20w/40. For your AutoLube or premix, always use dedicated 2-stroke oil. I've been using Lucas semi-synthetic, because it's available at the local AutoZone and seems to work well. My 1971 to 1973 shop manual says to use 10w/30 motor oil in the fork tubes.

Yes, motor oil in the forks is not just something you can do on the older models...  As Tom P. said, it's what they were designed to use.

(The switch to actual fork oil by Yamaha in the forks started sometime in the mid 70's)

Good info, thanks guys. I used about a tablespoon of 10w30 in the spark plug hole to lubricator the cylinder walls while I was testing my replacement stator. Figure once it’s running whatever is still in there will just be a little smoky but will eventually burn off.


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You're absolutely fine.  When I was a kid two stroke oil was not readily available....  Yamaha recommended two stroke oil but plain old 30 weight motor oil was listed as ok in the owner's manual too. 

I put a lot of miles on my Yamaha using Chevron Delo 400 30 wt.  It was what my Dad had in the garage.