oil leak

[54model20]

hope someone can give me a bit of advice ive just been out for a short ride on my 1954 model 20 about 40 miles when i got home i noticed oil on my right boot and on gear change rubber . the bike is running ok and only drips a bit from primary chain case when standing i noticed a bit of oil where oil pipe enters crank case ( front one) and wondered if there is a seal or something in there im no expert with speanners so would appreciate a few pointers before i do any permanent damage cheers guys

[Eric]

The connection is made with something called a Banjo Union either side of the banjo part should have a fibre washer. Drain the oil from the oil tank then undo the hexagon head of the feed connection (the front one) to check the washers.

You will probably find one has split or is damaged or the union may just have been loose. Replace as required and you may as well check the return one (the rear one).

Re-fill the oil tank and everyting should be OK.

[1608]

Beware, I thought the hose was loose on my feed (G12). Eventually discovered that the solder joint had failed on the short copper tube that is attached to the banjo.

[54model20]

thanks guys have some new washers on the way

[mikek1980]

my 54 G9 leaked from the stud for the dynamo, that also resulted in oil on the boots

[54model20]

how did you remedy the problem with dynamo

[Groily]

Should we infer your dynamo leaks too?

As to a cure . . . I have looked at 3 things.

First thing, make sure the oil seal in the bearing end cap on the drive end is good, and that the end piece is securely attached by the three small screws to the dynamo body. I use a gasket between end bit and main body. Oil shouldn't come out of the dynamo as there shouldn't be any in it - but seal failure can allow oil into the bearing housing and then back out the sides via a poorly-fitted oil seal housing. And some will get into the guts, which is messy.

Second thing, make sure the draw bolt plus nut is OK and that the dynamo securing strap is OK - and that both can be pulled up just reasonably tight.

Third thing, contrive a decent gasket for the joint between dynamo and the rear of the timing case. I have not found that a cork ring works well; nor an O ring; nor a flange gasket of ordinary thickness; nor any combination thereof.
I use a laminated gasket made up of several layers of decent gasket material with the dreaded gasket goo between each, thick enough to be sure that the dynamo comes up against the case evenly and squarely before any metal-to-metal contact can occur, at the machined recess/spigot or outboard of it. The design is suspect in that the drawbolt won't necessarily pull the dynamo up square owing to the off-centre position. 2 chunkier short studs and nuts would have been far better, but then we'd have to take the timing cover off to do it, and maybe remove the exhaust camshaft pinion to get to one of them.
I was plagued for ages by leaks there - which certainly covered the right boot on a good run, and forced a trickle of oil round the engine front right, towards the oil unions you mentioned initially.
But no more - not a weep, hint, lick or smidgeon.

As to the order of assembly, I have found that shoving the dynamo firmly into its slot, drawing it through on the drawbolt till the gasket is clearly being compressed all round, then nipping up the clamp/strap firmly but not hard, works best. Then I leave for a few hours for the goo to set before running. Particular care needed not to let goo into the timing case.
Others may have better ways.

[Steveajs30]

[Steveajs30]

My right boot is always oily, I use it to put the side stand down