New release - better gaskets

Wouldn't it be nice to have a silicone gasket that wouldn't squish out or lose its tension over time? You wouldn't need sealer. You could re-use it. You could tighten it normally like with paper gaskets. Sound like a dream? I was dreaming of such a gasket - some silicone with a fiberglass filler. Then I researched it and found out that this gasket material already existed. So "bang" I made up all the gaskets in my motor and now its oil tight.

Sure you can glue on cheap paper gaskets but then its a PIA to scrape them off each time you replace them. But the fiberglass reinforced silicone gaskets come off with no mess - and go back on the same way.

The other important thing is thickness. You don't want your gasket to be too thick - especially the timing cover because you need the same tension on the conical oil pump seal where a 1/16" thick timing cover gasket is not a good idea. Fortunately the fiberglass reinforced silicone comes in 1/32" thickness. It almost seems as if this material was made for British bikes. Someone had to do it and I didn't feel like waiting around.

Available JSM reusable gaskets:

Timing cover


oil junct block


Rocker covers


spindle covers


Tachometer drive

wow, are they also available for sale ?

@nixwiefort Jim has posted them on his website for sale - go and check them out!

http://www.jsmotorsport.com/gaskets.asp

Seems so:
http://www.jsmotorsport.com/gaskets.asp
Package deal would be nice though!

Nice one Jim.

I'll be trying some out for sure.

jseng1 said:

The other important thing is thickness. You don't want your gasket to be too thick - especially the timing cover because you need the same tension on the conical oil pump seal where a 1/16" thick timing cover gasket is not a good idea. Fortunately the fiberglass reinforced silicone comes in 1/32" thickness.

Timing cover

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This must be an atlas gasket. ??? No oil return hole, or points cable hole
And as most Atlas people know the early gaskets were even thinner than commando and very hard to find now. Even AN substitutes the thicker commando timing gasket for 20/Atlas.

True a 1/16" timing gasket is not a good Idea however ...in 28 years...I've never seen a 1/16" timing cover gasket?
None of the 3 brands of commando paper gaskets I have are 1/16". I have .028", .031", and .034" ...basically 1/32"

Nice stuff, Jim. Looks like a good choice for folks like me who tear down our engines with some frequency.

Ken

Dave -yes that was an Atlas timing cover gasket (its in my Cafe bike now). Thanks for pointing that out. The Commando gasket is below (and I edited the original post). I mentioned 1/16" thick gaskets because some rubber gaskets are that thick and I know of someone who special ordered a timing cover gasket from a gasket company that came out at 1/16" thickness (should be thinner). I checked the oil pump conical seal and there is plenty of compression with a 1/32" gasket.

Ken - Yeah these would be good for those who work on their bikes a lot. Especially a racer who doesn't have time to mess with sealer or gasket scraping (between races emergency etc).

Commando timing gasket

jseng1 said:

Dave -yes that was an Atlas timing cover gasket (its in my Cafe bike now). Thanks for pointing that out. The Commando gasket is below (and I edited the original post). I mentioned 1/16" thick gaskets because some rubber gaskets are that thick and I know of someone who special ordered a timing cover gasket from a gasket company that came out at 1/16" thickness (should be thinner). I checked the oil pump conical seal and there is plenty of compression with a 1/32" gasket.

Ken - Yeah these would be good for those who work on their bikes a lot. Especially a racer who doesn't have time to mess with sealer or gasket scraping (between races emergency etc).

Commando timing gasket

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Racer's set for $50 then

So Jim, are you making an Atlas/650SS timing cover gasket?
Rob

Standard gearbox and primary gaskets seem to turn to mush over time regardless of use (or not). I'd buy some of those in a heartbeat or even some of the sheet goods to make some.

Danno said:

Standard gearbox and primary gaskets seem to turn to mush over time regardless of use (or not). I'd buy some of those in a heartbeat or even some of the sheet goods to make some.

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I just haven't gone past the engine gaskets yet (except for the tranny inspection gasket I'm using and may put on the website).

These seem like an excellent idea. I was talking to someone about the possibility of gaskets like bees about a year ago and the general consensus was that it was going to be expensive to tool up for them so they thought it would not be done. I'm glad that you're doing it and plan on ordering a set.

Is there be a gasket for the MK3 Primary in the works?

speirmoor said:

Is there be a gasket for the MK3 Primary in the works?

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A primary cover gasket would be very expensive because of the amount of material involved. The material is pricy and arrangements would need to be made to use the wasted material in the center for other gaskets. This would have to be worked out and the cutter people don't like complications. Presently I am having some gaskets made by waterjet cutters and some are painstakingly hand crafted by yours truly because the minimums required by the cutters start adding up to thousands of dollars. So I'm working this out as I go. Other gaskets may be added and there may be some price adjustments (gearbox gaskets should be next). But I had to break these out right now because they work so well and I was amazed that no one else was making them - its a no brainer.

Danno said:

Standard gearbox and primary gaskets seem to turn to mush over time regardless of use (or not). I'd buy some of those in a heartbeat or even some of the sheet goods to make some.

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Danno - I added the tranny gaskets (and a few others) to my website, see below.

Robs SS - the timing cover gasket fits either Commando or Atlas magneto type. The triangular magneto gasket is nice because it doesn't need sealer and you can loosen the mag, move it to adj the chain and it will be oil tight again. I've never had such an oil tight (as in dry) Norton before.

Tranny cover


Tranny intermetiate gasket


Tranny inspection cover


Magneto Atlas style


Sump reed valve breather to case (Combat location)

speirmoor said:

Is there be a gasket for the MK3 Primary in the works?

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Cometic has the MK3 primary gasket in a nitrile rubber coated aluminium type, I just ordered one.
I think they have most or all of the other Commando gaskets as well.
I just had them make up a full set for my A10. If you provide them with paper or other patterns to copy, they do not charge for setup, just for the actual gasket. I guess the bonus for them is that they now have A10 gaskets in their data base
I've used the Cometic nitrile rubber and aluminium gaskets for a few years on the Vincents. They are very good, completely reusable many times and always seal , even with imperfect surfaces.

Glen

Nitrile is only rated up to 220 deg F. Norton motors heat up beyond that.
Fiberglass reinforced silicone is rated up to 500 deg F. Its much more longer lasting than Nitrile in hot conditions

Norton heads typically run around 300 deg F and can run up to 400 deg F or more. The cylinder base normally runs at about 230 deg F.

Nitrile has poor resistance to ozone which means that its starts to crack and deteriorate when exposed to the air (in about a month) it must be kept sealed in an airtight container. I don't want to have to worry about this. You can leave fiberglass reinforced silicone laying around in the air no problem. I'm sure nitrile works fine as a primary gasket but it won't last nearly as long a silicone in the motor where things get hotter.

I have some Cometic Nitrile gaskets that have been in a drawer for three years, no sealed container. They appear as new.
Cometic Nitrile Rubber/Aluminium gaskets are rated at 250f, not 220.
I've used them for years now on timing covers, cylinder base, tappet cover, magneto, intake, trans and primary without issue.
I will say that the silicone gaskets have the advantage of being easy to trim. The aluminium centre of the Cometics makes them quite difficult to trim flush with cases, if needed.

Glen

worntorn said:

I have some Cometic Nitrile gaskets that have been in a drawer for three years, no sealed container. They appear as new.
Cometic Nitrile Rubber/Aluminium gaskets are rated at 250f, not 220.
I've used them for years now on timing covers, cylinder base, tappet cover, magneto, intake, trans and primary without issue.
I will say that the silicone gaskets have the advantage of being easy to trim. The aluminium centre of the Cometics makes them quite difficult to trim flush with cases, if needed.

Glen

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I going by what they told me when I called Cometic. They said Nitril (also called Buna N) was rated up to 212 F deg (I rounded up) and they told me about the cracking in about a month's time when exposed to the elements. My own experience with Nitril cracking is with only with O rings. If you use them outside to seal things like I've tried on swingarms pivots and fender mounts - the Nitril starts cracking. Its the ozone that does it. Viton does better. Silicone doesn't seem to crack. I'm not knocking Cometic - just quoting them. They make a good product and their prices are cheap.

I could offer Fabric reinforced Nitril gaskets instead of silicone. What do you think I should do? Offer a lower temp gasket? Or one that I know is not going to over cook in this California heat I live in?