Hitchcocks Forum

Can someone please give me the lowdown on the EFI Unit construction primary chaincase. How is it lubricated ? There is no reference to oil change or levels in the manuals that I can see. Is there some sort of mist feed from the pump through the inner chaincase or what. There does not appear to be a level or drain screw. I've done 14000 miles on mine now without even looking at it and certainly not topped it up. Of course it could be empty - it doesn't leak !!

Thanks folks

It uses the engine oil I think.

Oil is fed through a hole between the sump in the crankcase and the inner face of the primary case. Same oil as the sump - it's unit construction. Change the engine oil and you have already changed the primary too. Tip the bike to the right when draining oil for most drainage from the chain case...

I assume that there is a drain hole from the inner chaincase to bring excess oil back to the sump so it doesn't overfill. Is that right ?

Think so... One drilling near the bottom at about the 7 o'clock position behind the clutch basket for sure. About the size of a 2 pence piece. Can't recall where any others are though, but some oil feeds through a gallery on the crank to the engine sprockets and sprag too I think?

Clive, I thought "Gods" knew everthing?😉

Yes they do Nettshubby. Everything except how the primary drive is lubricated on a EFI engine !

Don't forget Michael, all later uk bikes were unit construction but you still had to glug oil in the chaincase. The EFI engine has moved on a bit then. And all the better for that.

You still have to lob half a coke cans worth of oil in the chaincase after an oil change on the EFI too. Or so the book says...

"You still have to lob half a coke cans worth of oil in the chaincase after an oil change on the EFI too. Or so the book says..."



What? I'm looking at the workshop manual now and it doesn't say that (page 03-14). Nor does the owner's handbook (p63).

And it's sort of important to use an oil formulated for motorcycles as some of the additives in car oil can have detrimental effects on the clutch action.