The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: jfligg on 10.03. 2012 20:19

Title: A10 Rocker box gasket???
Post by: jfligg on 10.03. 2012 20:19
I was wondering if anyone has had any luck sealing a A10 Rocker Box with a 3 bond sealant or an RTV sealant with out using a gasket.  Thanks Jeff
Title: Re: A10 Rocker box gasket???
Post by: rockthedog on 10.03. 2012 20:25
hi jeff i tried silicone lasted 3 days ,mal
Title: Re: A10 Rocker box gasket???
Post by: Rich on 11.03. 2012 19:50
I have just fitted the copper gaskets from the USA, every time I ride it I get oil on the top fin left side, no oil on the rocker box and no sign of the supply pipe leaking, so suspect that I have not quite got it oil tight yet, 5 years of trying, still plenty of time left yet!! I wish you more luck than me
Title: Re: A10 Rocker box gasket???
Post by: BSA_54A10 on 12.03. 2012 10:12
Rich,
Wash & degrease the head thoroughly.
Go for a ride ( easy bit )
Come home remove the tank and liberally dust the head with some thing like talcum powder or cement powder.
In a couple of minutes there will be a trail directly from the oily fin to the culprit and I bet is is some where you thought would never leak oil.
Title: Re: A10 Rocker box gasket???
Post by: muskrat on 12.03. 2012 13:14
CEMENT POWDER I would use asbestos dust first. LOL
Title: Re: A10 Rocker box gasket???
Post by: Rich on 12.03. 2012 21:31
I may well give that a try as and when I get the time, I have a new toy to ride this year, I am going to swear now so those of a weak nature look away--------------a BMW R80 with a Hedingham single seat sidecar and Hedingham leading link forks
Title: Re: A10 Rocker box gasket???
Post by: trevinoz on 13.03. 2012 01:55
Jeff,
          Seeing as you are asking, I sealed the rocker box on the Flash with standard gaskets with Loctite 515.
So far, after some years, it does not leak at all, not even a smear.
I sealed the chaincase the same with the same result.

    Trev.
Title: Re: A10 Rocker box gasket???
Post by: BSA_54A10 on 13.03. 2012 10:17
Yes Musky cement powder works really well as it tends to set and stick to the engine when contacted with the oil.
Talc will tend to fall off so it is not as good for the job.
I have traced a lot of oil leaks this way for members over the years and usually the leak is no where near where they thought it was.
Prime candidates have been rocker shafts and head gaskets via a stud hole or if we are talking B40 / 44's blown cylinder base gaskets sending oil up the stud hole to the head.
Title: Re: A10 Rocker box gasket???
Post by: gold33 on 14.03. 2012 10:23
In answer to the original question... Yes, and yes it did work and still does work even after 2700 miles
I had a workshop reassemble my the top end after having new valve spring seats fitted, a bore hone and new rings. The first attempt using gaskets failed, I returned the bike to the workshop and they then used the silicone type gasket material, I haven't had a leak from the rocker box since.
Title: Re: A10 Rocker box gasket???
Post by: a101960 on 14.03. 2012 11:45
Just an observation. Loctite 515. USA Amazon price $16.99 (£10.81). UK Amazon price £36.72 ($57.72) Just what is it it about UK prices? I do not know wether the US price includes sales tax, but the UK price will be subject to VAT at 20%.

John
Title: Re: A10 Rocker box gasket???
Post by: Rich on 18.03. 2012 20:04
The oil was leaking from the front part of the rocker box face on the left side and also on the right side, today I removed the rocker box, cleaned the sealing face and set to with the pane of glass and grit paper, cleaned the head sealing face, annealed the copper gasket, then using clear silicone fitted the gaskets to the head, I then used a different silicone that is used to replace gaskets, cork and the like, on the rocker box face and have left this to cure. My thinking is that when I bolt the two together it will squash down and form a good seal.
I will find out later in the week
Title: Re: A10 Rocker box gasket???
Post by: bsa-bill on 18.03. 2012 20:52
This has been discussed earlier and elsewhere on the forum.
Comments suggested Copper Gaskets which I have still to get around to buying and also the fact that I have seemed to have cured the problem by making my own gasket (from gasket card).
The problem in my case arises from the fact that purchased gaskets do not match the outline of the rocker box, with very little gasket at one point around the joint (at the front of the rear section of the box)
Try a bought gasket on the head at that point and note how it misses the join
Title: Re: A10 Rocker box gasket???
Post by: jfligg on 22.03. 2012 23:43
Hi Guys I spoke to a friend of mine who has been playing with these bikes for 30 odd years uses aluminum gaskets.  So I am going to try that I'll keep you posted.  Jeff
Title: Re: A10 Rocker box gasket???
Post by: Rich on 23.03. 2012 19:49
seems to have worked, will be riding it out tomorrow for a longer ride so shall check it again when I get back home
Title: Re: A10 Rocker box gasket???
Post by: TT John on 15.05. 2012 11:32
As this seems to be an ongoing problem I thought I would look closer into it, It seems I had a leak from, what I thought was the rocker box gasket and as the oil was going all over the place when I went out on a ride, usually over the top of the cylinder was a pool of oil. After several attempts at replacing gaskets etc, I happend to notice a drop of oil on the tee piece that feeds the rocker gear, so this was removed and checked, then I saw it, the tee piece was silver soldered but one side there was a small crack which was hardly noticable. As I had no source of heat enough to re silver solder I cleaned it up and used soft solder on the part which I thought was leaking and after a 200 mile trip, no oil leak. Fantastic, after all these problems, its wonderfull to have it leak free. ;) *yeah*
Title: Re: A10 Rocker box gasket???
Post by: 0116harley on 15.05. 2012 13:16
This has been discussed earlier and elsewhere on the forum.
Comments suggested Copper Gaskets which I have still to get around to buying and also the fact that I have seemed to have cured the problem by making my own gasket (from gasket card).
The problem in my case arises from the fact that purchased gaskets do not match the outline of the rocker box, with very little gasket at one point around the joint (at the front of the rear section of the box)
Try a bought gasket on the head at that point and note how it misses the join
Bills idea worked for me. Brought some 0.8mm gasket paper, made the gaskets slightly bigger. 400 miles further not a drop of oil leaking from the rocker covers. Just gotta sort the other leaks out now
Title: Re: A10 Rocker box gasket???
Post by: Topdad on 16.05. 2012 11:30
I don't know if i've posted this before but here goes, inline with Bill's comments and fix, Lightning spares in Sale cheshire e-mail lightning-spares@-spares.co.uk used to make oversize gaskets , (i think they still do) which worked well ,could be a way forward ,i'm going to give them a call to see if they are still available and will let you all know the outcome regards BobH