Hitchcocks Forum

I know this topic has been aired plenty of times. I just wondered if anyone has had success with using a sealant (like Permabond 130) instead of the rubber O ring? On my 500 Twin I've tried just about everything - larger size O ring, sealant and no sealant, had the face of the outer case shimmed (surprisingly it was bowed outwards creating a gap in the centre, which it from where it still leaks). Using a torque wrench I've tried low tension on the central bolt, starting at about 8 lbs, checking for leaks and then trying more rising to 14.
I suppose the inner case might be deformed.
Anything I haven't tried? (positive suggestions only please).
Thanks

How about checking how the two halves meet with engineers blue so you can see where the gap is.

ok thanks for that- will give it a try

The same problem I had with my 500 Twin. I realized finally that the leak was between the mainshaft and the inner primary cover. Worth checking. Solved after installing new sealing there.

Pike beat me to it.
Gearbox shaft seal!
Check by cleaning everything first then after a run you will see where it's coming from.

How about checking how the two halves meet with engineers blue so you can see where the gap is.

I agree. I presume your twin is similar but on my Bullet I had to grind down the part where the bolt goes through when I found the two surfaces were still not touching no matter how tight the nut was. . Check this with no gasket and you will probably even be able to run a feeler gauge round the edge. I cheat a bit and put silicone sealer on the rubber gasket as well but it it now pretty much sealed.

Thanks for those suggestions. I've just had the gearbox out and replaced the oil seal. It's definitely running our of the bottom of the casing - I'll try the engineers blue and make sure the bolt facings are obstructing the sea. Chapter 10 in the battle commences!

Incidentally. I don't actually have any engineers blue so I degrease the surfaces then scribble on one with a sharpie....

Hi, had the same problem, to level the outer plate I sanded it down on a wet paving stone. Use a circular motion. It was surprisingly quick to do. Vince