Oil weep

[Andy_C]

I was hoping that my oil weep was caused by the lack of a sealing washer on the drain plug but no.

Was out on it yesterday and it was pretty hot, and I noticed a small drip from the engine after I stopped.

I put it up on my bench when I got home and could see oil on the underside of the engine from just in front of the drain plug to the rear of the engine, having a good look with an inspection lamp I could not seen any signs of a leak at the top of the engine, it all seems to be at the rear - about half way up the back of the engine.

I checked all of the case bolts and all are tight, also looked at the gearbox sprocket thinking it could be the oil seal, but no signs of leakage.

When parked up the amount of oil it drops is probaly less than a teaspoon full, it is just a couple of drips, but when in motion I guess it is dripping out and blowing towards then end of the engine.

I dont really want to take it off the road so I am going to keep a close eye on oil level, hope that I can run it this summer then look at fixing it over winter, guessing it is probably the seal between the cranckases.

Any thoughts?

[MickeyMoto]

There are two crankcase bolts internally. The heads are available if you take off the right casing.

Are you sure it is not from the breather pipe? It does blow from the join of the pipe at the crankcase.

Any evidence on the centre stand and front of swinging arm? It may still be the oil drain plug. Oil stains are a bugger to trace.

This is why I have switched to 20/50. I think 10/40 is a bit thin when the weather warms up. Just an opinion, but I'm sure others will disagree.

[3potjohn]

When I first rebuilt the Sport motor I made a mistake with sealing the two hidden bolts, resulting in a considerable leak from the right hand side.
A weeping clutch will run down under the left case.
If the dipstick is not sealing that can leak.
I recently developed a weep which in fact was coming out of the case bolt immediately behind the rear cylinder. I seem to have stopped that by coating the bolt with Threebond.

[Andy_C]

@ Mickey - I assume you mean the RH casing as sat on the bike, i.e. the one the starter motor would be housed in, if so I will pop the cover off and take a look.

Nothing signifigant from the breather or rear cylinder, or breather areas, yes it still could be the drain plug even though I fitted a new copper sealing washer, have to admit I did not anneal it as I assumed it would have been supplied in the annealed state.

I did put 20/50 in it when I changed the oil and to be honest I think that the weeping may have got slightly worse since the change which point to the washer so guess I had better drain the oil and anneal the washer.

@ John When I first had the bike there was a weep from the rear cylinder, tracked that down to head botls not being torqued down correctly. The rear case bolt behind the rear cylinder looks to be OK.

Apart from this I have absolutley no issues with the bike.

[MickeyMoto]

Yes, behind the starter cover. The nut is held in a hex cut out on t'other side.

Don't drain the oil until change time. If it is running well and the oil level isn't disappearing down the dipstick like the UK economy going down the pan then she'll be reet. Just a pain to keep clean.

[Andy_C]

Eeey Ooop Mickey I shall take a look at t' bolt.

At the moment the oil level is not dropping, so may well follow your suggestion.

I give the underside of the engine a wipe down with a piece of cloth after every ride, to try and keep it reasonably clean.

Now when I were a lad...........

Thanks.

[3potjohn]

My T150 was known as the Amoco Cadiz, so your leak has a way to go. People have used talc on a clean engine to try and identify the source of a leak. Can you even still get it?
Did you say your fill volume was 2.5 L?

[Andy_C]

Yes 2.5l.

I had a T150 like yours many years ago wasn't VC0 872M was it

[3potjohn]

KYT something I think. Only bike I forgot the number. T160 SVH681P was still about recently. My A65 MPL676L went past me once I could not run fast enough to catch the rider at the lights. Oh well…

[Andy_C]

Had a 150 and a 160 and enjoyed both.

Much preferred the 160 still one of the best looking bikes ever made IMHO.

If you ever see T160 reg No PYH 488R that's my old one.