Castrol 4T oil

[Truckedup]

Castrol website doesn't show ZDDP content of their bike oils...Castrol conventional oil is reasonably priced and I have several Vintage Triumphs with the engine oil shared with the clutch, but not the transmission. These old turds need a decent amount of ZDDP with a weight to protect the cams...Anyone seen a recent listing of the Castrol additive package? They also need a 20/50 oil because of engine internal clearances... Thanks

 

[jeff78]

Can't help with Castrol, but as alternatives, there's Valvoline VR-1 and their Motorcycle oils. Both available in 20W-50 and have healthy doses of ZDDP (>1300ppm for VR-1 and >1000ppm for M/C). Their motorcycle oils at least can be found pretty cheap at Wally world.

 

[Truckedup]

Can't use VR1 in the later 70's Triumphs that share the engine and clutch oil just like new bikes requiring a JASO oil...I believe the Valvoline 4T is around 1100 ZDDP.

 

[jeff78]

I've been running VR1 SAE 40 in my shared sump bike for almost two years and 20K miles and have had no issues with the clutch, but I get that some people are wary about running 'out of spec' oils.
If money is not a concern, Red Line motorcycle oils have over 2000ppm of ZDDP.

 

[Truckedup]

It depends on the clutch lining material....

 

[Silk]

The clutch on the old Triumph is not running in oil like a Japanese bike, the oil is for the primary chain, and a bit will get into the clutch. Any 20W-50 would be good, a V Twin 20W-50 even better, and Castrol 4T would be perfect for the job.

 

[Truckedup]

I work on the old heaps daily...the clutch plates do get wet with the correct oil level in the primary...

 

[Silk]

And they will slip with too much oil. After years of Triumhs and BSAs, when I got my Norton 99, when filling the primary case I'd put a glug or 2 extra in to allow for leakage. But the Norton primary cover with the big rubber seal didn't leak, and the clutch would slip....at 95mph in 3rd. It's only the later model unit engines that used the primary case as the engine breather, earlier models had the timed breather with the hollow inlet cam. Although I did convert my T100C engines to the later method, as I was using solid cams.