The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: oldbikerbill on 14.10. 2017 16:19

Title: Chaincase leaks
Post by: oldbikerbill on 14.10. 2017 16:19
My 52 A10 leaks from the primary cover joint after chagning my clutch plates.  Where in the US can I get a thick gasket, both of the ones I ordered were thin paper.  Anyone ever cut one out of cork sheet?
Title: Re: Chaincase leaks
Post by: Black Sheep on 14.10. 2017 17:19
A paper gasket should be sufficient. Did the gasket kink when you put the cover back on? Easily done.
Title: Re: Chaincase leaks
Post by: Greybeard on 14.10. 2017 19:36
If the case surfaces are flat you could just use a sealant; my choice is Blue Hylomar; no need for a gasket. Use a smooth file laid across opposite faces to keep the file flat. You might also slightly countersink the threaded holes. If you are using Allen screws tighten them with a screwdriver type handle rather than an Allen key to avoid over tightening.
Title: Re: Chaincase leaks
Post by: duTch on 14.10. 2017 20:00

 I think someone was offering to have some 'Cometic' (funny word, hey *smile*) chaincase gaskets made up, but maybe just for Swing-Arm models  *dunno*

 Mine tends to incessantly drip from either the drain screw or the tensioner bolt...Nice Plungie, and I don't mean to be picky, but hope the wiring (?) on the fender stay doesn't catch in the rear wheel or sprocket.....and maybe you've addressed it too, but the brake should work better if you rotate your brake arm anti-clock so it's at better angle to the rod (90ยบ @ full-on)

 
Title: Re: Chaincase leaks
Post by: Clive54bsa on 14.10. 2017 20:26
Don't buy the pale green ones that you see from time to time, they tend to slip out from the mating surfaces over time. Rocker gaskets do the same.
Title: Re: Chaincase leaks
Post by: KiwiGF on 14.10. 2017 22:56
My 52 A10 leaks from the primary cover joint after chagning my clutch plates.  Where in the US can I get a thick gasket, both of the ones I ordered were thin paper.  Anyone ever cut one out of cork sheet?

Not an answer to your questions.....but have you considered making your own out of gasket paper? I use a 1mm thick "flexoid" brand paper, some use old cereal boxes etc  *smile* it takes a while to make one but it stops you being reliant on suppliers, and you can make pretty much all your own gaskets once you have the punches, and a paper source.

I make the primary gasket deliberately oversize so that it sticks out inside and outside the case a bit, this is not an issue with the primary drive (might be with an engine gasket) and seems to make it less likely to leak, and it certainly makes it easier to make and fit, as a bit of misalignment does not matter, and it's less likely to rip etc.

You can't easily trace around the inside of the case (e.g around bolt holes) so I just do the cutting of the inside about 5/8" (from memory) from the outside trace. It might need trimming a bit to avoid hitting the chainwheel.

I stick the gasket to the inner then use a couple of long 1/4" whitworth bolts with the heads cut off, temporarily screwed into the inner case, to help guide the case on, thus avoiding disturbing the gasket goo you carefully applied. I only goo up the bottom edges.

If I can be bothered I trim off the excess gasket showing on the outside, using a blade.

The "wadd" punches I use were dirt cheap and one of my most used tools now!

I spend more time trying to prevent leaks from the case bolts, rather than the case joint  *problem* *work*
Title: Re: Chaincase leaks
Post by: muskrat on 15.10. 2017 13:06
I too make my own gaskets either 0.4 or 0.8mm. Once every 10 years I buy a gasket kit and use them as templates to mark out my own. I buy 1 meter wide x a few meters long in those thicknesses at about $25 a meter. That lasts me many years. Less than 5 minutes to make a primary gasket. The US would have to have a supplier like this   http://www.swiftsupplies.com.au/oil-jointing-general-purpose-gasket-paper
Cheers
Title: Re: Chaincase leaks
Post by: a101960 on 15.10. 2017 13:20
Quote
Mine tends to incessantly drip from either the drain screw or the tensioner bolt
Mine used to do that then I bought some of this stuff  https://www.permatex.com/products/thread-compounds/thread-sealants/permatex-high-temperature-thread-sealant/ seals the threads but does not set hard so nice an easy to unscrew when the time comes to do so.
Title: Re: Chaincase leaks
Post by: t20racerman on 15.10. 2017 19:56
I gave up and bought a belt drive clutch that runs dry. A bit radical maybe, but it transformed the bike - smoother, quieter and no more leaks.
Worth every penny 😁
Title: Re: Chaincase leaks
Post by: kiwipom on 15.10. 2017 21:57
hi guys, yeah I too make my own, I scanned all the originals then I can print them on gasket paper, works for me, cheers
Title: Re: Chaincase leaks
Post by: worntorn on 16.10. 2017 00:04
You could check with Cometic Gakets, USA, they might already have the pattern.
They now have everything on file for later A10s, not sure about the early bikes.
The Cometic gasket has an aluminium coated core  with rubber both sides. They seal completely and can be reused indefinitely.
 When you switch to a Cometic, it's the last gasket you will need to buy or make for that particular joint.


Glen
Title: Re: Chaincase leaks
Post by: duTch on 16.10. 2017 04:07

 I've already said plenty times, I also use ~0.8mm paper to make my own, and use 3-Bond both sides stuck to outer case, but silicon grease on the inner case to aid removal and re-use
Title: Re: Chaincase leaks
Post by: Zander on 16.10. 2017 07:14
During the rebuild on my GF I was short of said gasket, having managed to break the new one I'd bought, so I used the cardboard backing from the large envelope that the gaskets came in to make one.  I greased it on both sides and its been on and off a couple of times and seems ok.  Needs must etc..
Title: Re: Chaincase leaks
Post by: bikerbob on 16.10. 2017 08:47
My tips for making your own is use the casing as a template, that way you get a better fit around the outside of the gasket also punch the holes in the gasket before cutting out and I find it easier to cut the inside of the gasket first then the outside. While you are making one you may as well make two then you have a ready made spare. Finally I do as dutch does and fix the gasket with adhesive to the case and a smear of grease onto the other side of the gasket makes it much easier to remove and as long as both surfaces are flat I do not get any leaks and I use 0.4mm paper. You can buy a roll off ebay quite cheaply and will last for years.