Rigid A7 engine breather fault?

[Jim Griff]

Hi All,

I'm after a bit of advice. I went out for a good run today on my 1948 Rigid A7 and when I got back I found quite a bit of oil around the right hand silencer, oil tank, gearbox. It looks as if all my fibre washers etc have gone, but one curious point is that the seal on the oil tank cap also seems to be leaking as oil was evident from the cap.

I'm just wondering if my breather is blocked and is creating negative pressure, forcing oil back and causing the leaks including through ther oil cap (my washers, etc are recent so I think something else is at fault here)

Suggestions on checks etc would be greatly received

Jim :-/

[52t-bird]

Hello,A simple answer is BSA and others with gear oil pumps wet sump when left standing i.e the oil tank contents drain into the sump. If you started the bike with the sump full of oil that could/would cause excessive pressure until the oil was scavenged back to the correct level. If you topped up the oil tank before the ride it would also explin the oil tank cap oil leak as once scavenged back the oil level in the tank would be too high.If you are aware of this and either have some form of oil line block(not recomended) or drain the oil from the sump if the bike is left standing then you need to look elsewhere. For the record i am against oil line taps or valves and take the advice of the T160 owners club that the best cure for wet sumping from standing is to ride the bike!!!

If you havent recently reassembled the camshaft oil breather it is unlikely to give trouble in service. Take the timing cover off and make sure the breather does not have any end float as if it does that will need the inner cover removed and new cork shims fitted to remove the end float.
Failing that it may well just be you have one or more broken rings causing crankcase compression and only inspection will answer that.
good luck! Regards David

[Jim Griff]

H iDavid,

and thanks for the response. To answer your question though, no it's not wet sumping and doesn't seem to suffer from this either. I agree with your thoughts on the anti wet sumping valves, too easy to forget and leave closed with disasterous results! The T160 owners I feel have the right answer!

I'll check for any line blockages and additionally check the breather.

Thanks again
JIm

[fidobsa]

You could also do a compression test. If one cylinder is losing compression into the cases it will give a lower reading.