BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: chrisx1 on 20 Mar, 2026, 10:49

Title: Primary lubrication
Post by: chrisx1 on 20 Mar, 2026, 10:49
Has anyone used chain lube instead of oil in the primary?
Title: Re: Primary lubrication
Post by: DAVE BRADY on 20 Mar, 2026, 11:26
Hi,

Never used chain lube.  I would suspect that as with a rear chain, over time it would get flung off and result in a dry chain unless sprayed before each ride.  Also the the primary does hot unless you have a vented case.  The oil gets splashed about by the chain on its bottom run and so keeps the sprockets oiled as well.  There is also the cooling effect of the oil splashing about and running down the inside of the case.

Dave.
Title: Re: Primary lubrication
Post by: Catz on 20 Mar, 2026, 12:11
Quote from: chrisx1 on 20 Mar, 2026, 10:49 Has anyone used chain lube instead of oil in the primary?

Do you mean lube in an aerosol or something like Scottoiler lube?
I've got a Scottoiler on three of my bikes and i always re-fill them with engine oil or fork oil or whatever i've got handy. So if you're thinking of Scottoiler lube then just use the oil designed for the primary case. That's my take on it. ;)
Title: Re: Primary lubrication
Post by: limeyrob on 20 Mar, 2026, 12:41
I would not use anything like that in the primary.  The primary oil is lubricating the clutch inner and basket and the clutch rod and bearings. Its also keeping the oil seals wet.
You could dismantle the clutch and grease pack the inner roller bearing but oil is better.
Title: Re: Primary lubrication
Post by: chrisx1 on 21 Mar, 2026, 17:10
Thanks for the replies.
Title: Re: Primary lubrication
Post by: V500 on 21 Mar, 2026, 18:15
I have, as a stop-gap measure.
No problems with it.
Title: Re: Primary lubrication
Post by: DAVE BRADY on 21 Mar, 2026, 18:48
Hi,

How long was it used as a 'stop-gap'?

Dave.
Title: Re: Primary lubrication
Post by: idie on 21 Mar, 2026, 22:49
The chain case oil doesn't just lubricat the chain, it does the clutch chain wheel bearing. It also lubricates the the crankshaft shock absorber.
Title: Re: Primary lubrication
Post by: V500 on 22 Mar, 2026, 09:38
Quote from: DAVE BRADY on 21 Mar, 2026, 18:48 i,
How long was it used as a 'stop-gap'?
Dave.

Most of last Summer, until I could get around to resealing the chaincase properly. A few squirts of oil on the moving chain via the filler hole is adequate too.
Additionally there's usually enough oily mist in the primary chaincase to lube the crankshaft shock absorber and clutch components, especially given the "Sunday afternoon" use the vast majority of our bikes now get.
Title: Re: Primary lubrication
Post by: DAVE BRADY on 22 Mar, 2026, 09:57
Hi,

I can see that for short occasional runs it would be adequate but as said as a stop gap.  A bit like rear chain lube, the more riding the more often the lube needs to be applied.
It does not take long for a dry chain, either front or rear, before it can be reduced to scrap and damage to be caused to the sprockets.

Dave.