Primary oil

[65restoration]

I have a 65 panhead on an Electraglide frame and need to know if the oil in the primary is the same as in the engine. I have heard two different stories and I know someone out there has the real story. Please help as I just picked this up a couple of weeks ago and am trying to get it fired after sitting in a shed for 30 years. ???

[vintagehd]

Really I think it is a personal thing...I run 50W in both oil bag and tranny...some run thicker in tranny...as long as you have some in it...no help I know but my opinion...V.

[03Roadking]

65Restoration
Do you mean the transmission like vintagehd is referring to or do you really mean the primary case that the chain from the motor to the trans is enclosed in?

[VPH-D]

The oil in a hard primary comes from the engine and is scavenged back to the oil tank. A hard primary set-up must not have any leaks, or it won't be able draw back the oil. Some people isolate the primary and fill as required. I remember something about not returning harmful crap to the engine. I use the factory oil line routing on the Shovel I've owned since 79, and have had no problems.
VPH-D

[65restoration]

This is the oil between the engine and trans. I was told that there were three different oils in the Harley, engine, trans, and primary but I also was told the engine oil provides the lube for the primary drive to the trans. Thanks for all the help and hopefully it will come alive tonight. I did get a manual but it is vague. Thanks again

[fourthgear]

Its as VPHD has said the primary chain is lubricated by a valve screw on the oil pump and breather venting into the primary case from the motor. What ever oil type /weight you have in your oil tank goes to the primary and scavenged back to oil pump and then back to the oil tank. As has been said , the primary case has to be air tight for it to work properly. I have changed a few to the new type HD's meaning a sealed primary system with its own type of oil. The trans has its own oil , separate from motor/primary and there are diff. weights of oil you can put in there , I use Synthetic 75/90 gear oil in mine.

[65restoration]

Thanks fourthgear, this helps a lot and I am slowly learning about the Harley's. Good information.

[Cotten]

To make it worse, there were running changes in production that affect the vacuum return on the '65.

By now most have been updated to a drained starter housing with an o-ring in the deflector plate to isolate it. (They drew rainwater into the startermotors!)
And later '65s had a larger breather hose to the oiltank, as somehow that affected the draw on the enclosure, maybe.

The idea of separate oil for motor, primary, and tranny is an Indian thing. But basically so is the Harley aluminum primary enclosure!

....Cotten