Why is it so hard to find this info?

[White Horseradish]

I decided this is the summer that I WILL ride my motorcycle. To further that goal I ordered the two things I know it needs (mirrors and clutch), got my learners permit, and started reading the Clymer manual on clutch replacement. This would involve draining and refilling the oil. I can't figure out what kind of oil that is supposed to be. Everywhere on the web and in the manual it only tells me the capacity, but not the weight "Consult your owner's manual" my foot. If I had an owners manual I wouldn't be looking all over the web. Oh, and someone is offering the manual for $50. 

Seriously, is this such common knowledge nobody bothers writing it down? Or is it a closely guarded secret revealed only to a 20th degree mason with halitosis? Or am I just failing miserably at searching?

[zxcvbob]

My Google-Fu says you need an oil that is JASO-MA certified -- like Shell Rotella T.

[Tuco]

What kind of bike?
Back when I rode, the 1970-1988 YaHondZuSakis all took motor oil, e.g. 10w-30, in the bottom.

Call your nearest dealer, ask if they have gearbox oil for your bike.  They just might tell you.

[White Horseradish]

What kind of bike?

1980 Honda Twinstar. It ain't much, but it cost me $100

Back when I rode, the 1970-1988 YaHondZuSakis all took motor oil, e.g. 10w-30, in the bottom.

HA! That's perfect!

Call your nearest dealer, ask if they have gearbox oil for your bike.  They just might tell you.

That's an idea. It will have to wait for tomorrow, I don't think they are open at 8pm.

[RoadKingLarry]

Castrol 20w-50.
Rottella T 20W-50

[White Horseradish]

And this is why APS is my go-to board for just about everything. Thanks!

[never_retreat]

If its just a gear box almost anything would work. Transmissions only get funny because of the clutches.

[RoadKingLarry]

Just use a diesel engine spec oil. Most everything else is designed more to protect the cat converter than it is the engine.

[Antibubba]

Per Wiki, it's one of these:

CM 185T -- 1978-1979 Twinstar (6v)
CM 200T -- 1980-1982 Twinstar

All the manuals you could want:  http://www.repairmanual.com/category/1980-honda-cm200t-twinstar/

Some other cool sites:

http://www.velocepress.com/
http://oldmanhonda.com/MC/MC.html
http://www.cyclechaos.com/wiki/Honda_CM200T

I have most of a '64 CB77, and I've supplied you with several months of my own searching.  You can pay me back by posting pictures.   

[White Horseradish]

Per Wiki, it's one of these:

CM 185T -- 1978-1979 Twinstar (6v)
CM 200T -- 1980-1982 Twinstar

It's a CM200T. Soon as I get to work on it I'll try to remember to take some pics.

[griz]

I worked at Honda dealer about that time.  Honda even sold their own brand of oil, or at least it had their label on it.  All the Japanese bikes of the time used oil comparable to what you would put in a car.  10W-30 was the most common, today's 10W-40 would be a little better.  I would stay away from the more modern 5W-30 and other thinner oils.  Your bike (and most bikes) uses the same oil for the engine and transmission, so don't venture too far from the normal weight oil.