Silicone rocker cover gaskets

Andy Higham · 2026-02-27T07:39:20-0700

An offer has popped up on my Ebay page, White silicone rocker cover gaskets.
Has anyone tried these? Are they rigid enough not to get squidged out? Do they keep the oil inside? I assume they are re-useable

kommando · 2026-02-27T08:14:12-0700

The ones I have are Red and bought many years ago, reusable and leak free. They are thicker than a standard gasket so you have to be light fingered on the nuts or they do bulge out. How well white ones on ebay will do ???

Andy Higham · 2026-02-27T08:24:50-0700

Suppose £10.35 isn't a big risk

AndyDMC · 2026-02-27T08:44:18-0700

Andy Higham said:
An offer has popped up on my Ebay page, White silicone rocker cover gaskets.
Has anyone tried these? Are they rigid enough not to get squidged out? Do they keep the oil inside? I assume they are re-useable

yes, I have them on the Dommi. Excellent, re-usable, I use just oiled, no sealant, no leaks (not even misting). As with all silicone gaskets, I find the compressibility concerning, but I guess just check them after a few miles, as they never really snug down tight like paper ones.

So yes, they do get a bit sqidged out, but re-calibrate your internal torque wrench, and use if often initially until you are happy!

And yes, re-usable
Andy

Lineslinger · 2026-02-27T09:41:06-0700

I purchased mine from "Real Gaskets" in Tennessee, USA.
The ones I purchased are red so maybe a different compound?
Great gaskets and pricey.
They maintain their integrity really well as long as you don't over tighten them, like I did and I thought I was going easy in terms of snuggling them up....not really tightening.

I called them and asked about installing and tightening using the castle nuts and a single stainless washer.
They recommended....
Install them dry. Clean both the cover face and the face on the head with alcohol and wipe completely dry.
Place the gasket on the studs, put the cover in place and tighten 10 to 15 INCH LBS. not ft. Lbs. alternating tightening sequentially back and forth.

Fast Eddie · 2026-02-27T10:24:45-0700

I went back to standard gaskets for the rocker covers.

I think silicone ones are fine for covers with lots of screws, like the timing cover.

But for Norton rocker covers, I just feel that the low torque specified increases the risk of losing a cover!

Yes, you could drill and lock-wire the nuts, but then again you could just use paper gaskets and a decent ‘nip up’ !

Just seem like a solution in search of a problem to me.

YMMV.

Andy Higham · 2026-02-27T10:32:37-0700

The ideal situation would be if they had inserts, slightly thinner than the gasket that can be torqued down on to.

Schwany · 2026-02-27T10:58:18-0700

I use JS Motorsports gaskets. They work, but do squish out some. If squishing out gets your anal device in an uproar, you'll have to go with paper.

I had white silicon gaskets on the pushrod tubes of a 60's something 650 Triumph. What a mess. Talk about a problem looking for a solution. Didn't find out until 56 years later how to keep oil inside those pushrod tubes. Bike was long gone by then. If I were 40 years younger I'd buy another old Triumph and see if I could keep the pushrod tubes from dribbling. I would not use silicon rubber alone though.

jseng1 · 2026-02-27T11:06:39-0700

Regular silicone sheet can squish out, loosen up and leak - sometimes enough that the nuts will come loose. The solution is fiberglass reinforced silicone that does not squish out and loosen up like regular silicone does. You can torque down the fiberglass reinforced silicone gaskets the same way you torque down paper gaskets - they stay tight and leak proof. Close up view below shows the fiberglass:

ashman · 2026-02-27T15:35:23-0700

I been using Jims silicone rocker gaskets for years and have never had any issues with them, I never use a torque wench when working on my Norton except for my main head bolts everything else is done by my torque hand/feel been doing this for near 50 years of owning and working on my Norton and other British bikes, works for me and have never had any problems with lose nuts and bolts.

Ashley

AndyDMC · 2026-02-27T15:53:36-0700

Fast Eddie said:
But for Norton rocker covers, I just feel that the low torque specified increases the risk of losing a cover!

Yes, this was my concern. But I did 1000-odd miles round Europe and no issues. Definitely to keep an eye on initially if fitted tho

Yakatak · 2026-02-27T16:23:09-0700

I use silicone gaskets (or Jim's hybrids on everything applicable. I just use a little blue locktite for peace of mind.

Silicone rocker cover gaskets

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