What's in your primary?

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About to fill all of the parts requiring oils on my '69 750 S for the first time. Engine is getting Castrol 20W/50, gear box 80W/90 EP.
Every reference book I have is 30-40 yrs. old and even they aren't consistant with one another. I'm sure that there are more modern lubes recommended for the primary and forks nowadays.
Your suggestions/ experiences are appreciated.

Thanks in advance,

Tom
 
Harley-Davidson primary case oil or ATF depending on whats on hand. Going belt so nothing in the future.

Hope that helps.
 
Mine is missing, pitched it to save weight. Has a 40mm belt in it's place. One less thing to leak.
 
ATF. Helps to see if you have a seal leak from the crankcase, too, if you find oil in the ATF.
 
In about any drive train that contains friction plates most of last century ATF is the fluid of choice. Many if not most belt drives can be run in ATF or oil, cam belts for instance, same with our primaries, but then half the joy of belt drive is lost. ATF is perfect for chain drives even w/o clutch plates. If been used by Brit Iron owners for decades now, just takes time for news to spread I guess.
 
I put 50W Havoline Racing Oil in the oil tank, kind of like honey, and the same in the primary, which is what the Riders Manual called for. Of course that will last about 50 miles and then get changed. Right now I only have 10 miles on it, so there is a bit to go yet. I'm not sure what I'll really end up putting in either, but probably something different. I am of the opinion that if it has oil and it's clean and full, it will be OK. But then I am not racing it either.

Dave
69S
 
If general the faster stuff turns the thinner the lube should be.
 
I've always used the same stuff I put in the engine. Old school green 20W-50 made by Brad Penn in the old Kendall plant.
 
I use Dextron II or power steering fluid in forks, Ford type F in primary with clutch, Dextron II in AMC gear box. I use 140 gear lube in my '38 JD tractor and in Commando if ATF not on hand at the time, then hold back on how long I rev hi in low gears, or it turns the interface of sleeve gear bushes and shaft to a caronized metalized dry ceramic abrasive.
 
[quoteFord type F in primary.quote]

Not that big of deal but F type has friction modifiers to help friction bands in Ford automatics to grip where Dextron does not, so might let clutch plates slip though I did not have an issue - even had to ease off my Combat's 1st to 2nd shifts entering hwy steep because the acceleration would hesitate d/t tire spin w/o wheelie. Even made a chirping sthat fooled me as clutch slip for a while.

Less drag is just predicable if ya switch between them one ride to the next. Slick shifts are also noticed though AMC gearbox is a sweet delight heavy or thin oil.
 
I never seemed to have any oil on my clutch plates even if there is oil in the primary, it just seemed to leaked out that stupid sliding seal around the trans counter shaft. But I'm not sure there wasn't oil leaking all over the place anyhow. Exxon Valdez or BP Horizon.

Dave
69S
 
Over a number of decades using atf and whatever extra oil I have left in oil containers has been used in all my old bikes primaries and I haven't noticed any difference in performance good or bad with any of the oils or atf
 
Primary = JASO spec oil as it is supposed to be for wet clutches and can sourced cheaper than ATF now, so if gets in clutch it does not matter, Engine = Tesco fully synthetic oil, better performance than straight single grade oil from cold, runs cooler, and less crude on the magnetic plug I have noticed, and cheaper than single grade oil of dubious quality. Used with a quality MANN filter for synthetic oil I have noticed the oil in the tank does not go totally black like it used to.
 
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