rocker box leak

[a101960]

Copper gaskets are good, but for a really effective seal they need to be used with 3 bond. Mine always leaked fom the L/H exhaust valve area, and the reason for this is that at that point the cover and head surfaces do not line up very well. They are slightly out of alignment so subsequently it is not a good match in that area. I tried many times to get a good seal without success. It would be OK for a while before it started to weep and then getting progresivley worse. Copper gaskets with 3 bond have thankfully resolved the issue.

[CheeserBeezer]

Halfords sell a Loctite product ref: MR5922 (from memory) in a white 'toothpaste' tube. This is the best gasket paste I've ever used for conventional joints. I find with rocker boxes it is necessary to flat the surfaces, use good quality gaskets that aren't too thick and tighten the box down very tightly, then go back and retighten. The problems are that the pushrods and valve springs are trying to lift the rocker box off the head, the head steady is vibrating the rocker box on the head, and generally it's not one of BSA's finest designs. Coupled with the fact that it is difficult to fit without smudging the paste and damaging the gaskets we're up against it! However, using the above I've managed to get (most of!) my rocker boxes reasonably leak free.

[BagONails]

I have had leaking RB's since owning the bike and lived with the mess until now. After a full weekend of riding two up, my wife started noticing specs of oil on her jeans!
Maybe its time I got into this and sorted it out I thought so without further ado it was tank off, carby off, zorsts etc.

I found more RTV than I've seen in a long time, PO was a true exponent of the art and as I go around the machine fixing his bodge ups the blue lines have been gradually diminishing. At least I can see where I've been! All joking apart I'm very glad I bit the bullet and got stuck in as look what I found!  I will start another thread for this broken valve spring collar but a fortuitous intervention to say the least!

It seems he tried copper gaskets but I'm not sure they are meant to be slicked in RTV like this? Anyway I have a bit more work to do now than I initially thought but do count myself lucky that I got to this before finding out the hard way...Thanks to the missus for having a moan too, cor never thought I'd be caught saying that!

[Worty]

Nice one BoN - did the broken bit end up in the engine?  Exhaust side a bit better than carb side I would reckon as no-one wants to lose bits down the pushrod tunnel.

Still trying to find a benefit from a moaning wife myself

[BagONails]

You'll have to switch to the new topic for further updates Worty but yes I found all the bits fortunately. Now to find out what's wrong...