Yes Bruce, it was no ones fault but mine
I SHOULD gave checked the specification of the oil before I used it rather than making an assumption that being a modern oil it would be syncro safe ( usually way to note a non sulphur oil )
Sulphur oils will attack the grain boundry region of most copper based & some zinc based alloys which causes them to crumble .
I know that I was in a previous life a non-ferrous foundry metallurgist and prior to that an alalytical chemist for a foundry that made secondary foundry ingots.
And while it happens faster at higher temperatures, it still happens a lower temperatures.
Also the local temperature can get a lot higher than 250 C
The oil is also electrolytic apparently to do wit the electronic sensors in the gear box which makes things worse, but I would have expected the Cu-Al circuit to be a lot stronger than the Fe-Cu cell but circumstances were to prove that wrong.
Usually you only find sulphur in truck & tractor oils so I was surprised to find it in this stuff.
So I stuck the remaining 23 litres on evilpay and was floored when it got $ 18 / l .
The box needed a good rebuild having been through "best of the bad" rebuilds / repairs over the past 30 years
As stated I choose to use the oils I use for the reasons I mentioned .
As for using the original specification oil that would be impossible as that has not been made for near 50 years
And I was not trying to start an oil debate, just to highlight just how robust the horseshoe boxes really are.
In fact nearly all BSA boxes are full of gears cut from forged blanks , way over engineered for the relatively low output of BSA's in general and definately over engineered for our M series bikes .
I used to run Royal Purple in the box because it was in fact purple
Primary was dextron
Thus purple spots = leaky box
Red spots = leaky primary
black spots = engine leak
For this ride I geard up the bike as I was riding with Shane on his speed triple & I did not want hin to wear out his 2nd gear going slow enough not to leave me behind as we went down via Goulburn & Crookwell then Borrawra because the servo at Crookwell was closed and most of those roads are fairly strait fas roads , not really where a WM20 shines .
However I ran out and it was going to be a big 3 day weekend ride in & ride out so I used some VolTrans that got ages ago at a auction.
This was on the assumption that it was going to be fine as it normally goes in Volvo auto boxes & diffs and the syncro cones in auto boxes are a bronze powder pressing
Well it wasn't
What really floored me was the layshaft bush worn oval
