I just purchased a 1974 FXE Super Glide and it has been recommended that I isolate the primary case from the engine via disconnecting the chain oiler hose and primary-to -oil pump hose due to the potential of crap from the primary case being sucked back into the engine.

Q--if I do this, will it hurt the clutch if I fill the primary with oil to the level of it just touching the primary chain, in order to keep it lubed?

Q--will blocking off the feed and return hoses affect the engine breathing/ venting?

 

your engine vent most not be changed - the small feed pipe from the oil pump is plugged and I leave the small hose connected to the inner primary for it, and run the hose over the trans so the primary case has a vent - the vent into and oil return out of the primary can be tied together so nothing leaks - then replace the vent line and T with a single hose from the block vent fitting to the oil tank -

I use 70W oil one cup in a measuring glass - early bikes don't have a removable derby we use the foot rest door but you have a derby pore it in that one

it works just fine that way

 

The chain oiler can just be shut off, hose cut, and then use the part in the primary as the vent. The return to engine line can just be plugged. It just uses internal engine vacuum to suck the primary oil back.

I use ATF in my isolated primary's, you just need enough oil to catch the starter ring gear teeth. If you put too much oil in, it will eventually gum up the discs and you'll need to clean them. I think it's only take around 4 oz of fluid. If you're using original frictions, they will likely gum up eventually anyways, but I haven't had to clean any after switching to the red Alto discs; they seem to do better. (I have 4 or 5 bikes set up like this)

 

They make wet clutch disc...the only difference is they have grooves in them so the oil can sweeze/sling out. I have always run a quart.

 

If you are going to isolate your primary.

 

Thanks for this info-- it's exactly what I was looking for.