Possible gearbox case crack or not ?

[bevanclark]

Hi folks, I haven't had need to disturb the gearbox drain plug since I got my 1950 VB a while back, but while doing an inspection I noticed what may or may not be a crack
I've attached a photo - sure looks like a crack, but when zoomed up a bit, maybe not. What do you think ?

Does the appearance of the casting look typical for a G107J box ? Seems odd to have a shoulder only part way around the drain plug.
Cheers,
Bevan

[Pete.Silson]

It just looks like a normal casting mark to me.

Incidentally I don't think that BA boxes have a "drain plug" as such, the grease just exits of it's own accord through various orifices. The plug is just there to access the speedo drive worm gear.

Pete

[nevhunter]

Just part of the coring used for the casting. Wouldn't hurt to clean it out in there and put some clean grease in. Sometimes water gets in from the top Cable fitting. There's no drain plugs on a BAP unless you tap out a hole for it near the lower mount and use a taper thread plug, as there no metal thickness to spot face it. Nev

[bevanclark]

Thanks guys, one less thing to worry about

[paul.jameson]

I haven't seen the underside of a BA box look so clean since the last time I did a major rebuild of one. Normally, there are signs of grease leakage. Just to be sure, I would advise removing the gearbox filler plug and poking something down into the box to see if there is any grease in there.

[bevanclark]

Thanks Paul,
Yes, it definitely has plenty of grease in it. Although I haven't removed the drain plug, I did actually have the cover off a few weeks ago so I could remove the mainshaft in order to replace the worn gearbox sprocket and had been concerned that a crack may have resulted.

With new sprockets and chains and some magdyno woes now resolved, the VB seems in pretty good fettle so is ready for the approaching summer here. It is the least powerful motorcycle I've ever owned, but probably the most fun to ride; the sound of it chuffing away was worth the eye-watering cost of importing it !

Anyway, Geoff Brown's article in the October Cheval is a timely reminder to check your gearbox oil/grease levels !

Cheers,
Bevan

[garycullen]

Bevan, I hope you are using a grease oil/oil mix?
If just grease it will spin off the gears and shafts and collect on the case insides.
I use a grease oil mix from Aegis oils. ( Paul Radisich company based in Turua.)
They assure me the grease component, a Molylibdimin base ( I probably haven’t spelt that right ) in the mix will not destroy the bronze selector calipers.
https://aegisoil.co.nz/
I find them very helpful and I use their oils and greases for my 1933 Austin 10.
Cheers
Gary

[bevanclark]

Gidday Gary,
I bought a big tub of Amtex Viper 00 semi-fluid grease for my Panther's Burman box, so have topped up the VB's one with that. It is pretty runny, so hopefully o.k..
Cheers,
Bevan

[garycullen]

Haven’t heard of that brand.
I would check it is not an EP specified mix. Seems that a lot of EP has acids that eventually eat bronze.
So maybe your selector calipers and the two bronze bushes may be at risk.
EP is Extreme Pressure grease.

By the way I really liked your picture of your VB that was used on a recent Chevalier der Fer magazine!

I am still having problems getting my VB to reliable start each time I try.
Have to sort this out before I go for re-registration…
A brand new Amal 276 from Burlen Fuel in the UK with jetting for VB hasn’t fixed it!
Cheers

[garycullen]

The Amex web site tech data sheet describes a copper tarnish test they do.
Can’t find the resulting number for the Vipe 00 though…