To Cylinder Base Gasket on Not?

The Norton Tech Digest says the early 850s deleted the base gasket and the later ones reverted back to using it. Current thinking?
Any idea why this was deleted on the 73s only?

I do, it is a lot to take apart if it leaks.
Put my favourite gunge of the day on it as well.

I don't bother with the gasket. I use Loctite 574 multigasket, its an anaerobic and doesn't leave rubbery lumps inside the engine.
It hasn't blown yet but has the advantage you could partially lift the barrel and reseal if you had to.

I've read that they brought the gasket back because dodgy mechanics were filling the rear drain with silicone. Provided that you're careful then there should not be a problem with deleting the gasket.

I wouldn't discontinue the gasket without at least checking for a wear ridge in the bores as this would give the top ring a hard time if not attended to.

I suspect the real reason for Nortons trying to do without the gasket on the 850 is that the through-bolt system doesn't facilitate re-torquing. I follow the practice of removing the head to re-torque the through-bolts after 100 miles but this means doubling up on the head gasket re-torquing and probably an extra gasket as well.

If one tightens only the accessible flange fasteners on an 850 then the through-bolts will effectively be doing nothing except acting as bump stops for the cylinder !

As advised above >>>

If bike is not on edge of detonation tune, then only reason for
base plate is extra oil and clearing solvent pollution and subtracts
from the already marginal stability of barrel on cases.

If ya really run up to redline in anger at times, I've found
the Yama-Honda-bonda grey thick crap will be hammered in the
seam slap to crush and fracture to weep>leak. So only goop
my Cdo's will ever get on purpose is Hylomar Racer Blue.
Also a bugger to get cases split again, not with Hylomar.
Them Brits knew a thing or two way back when on sealing.

For the anal like me, its a few less ounces inertia and mass
to fling around or lift back up right.

hobot

No base gasket here, just Wellseal. It's been noticeable that the barrel nuts have needed re-torquing (by my calibrated spanner-holding hand!) a couple of times, but I have no plans to lift the head to get at the outer bolts.
Not 100% relaxed about this, but that's how it is.

ludwig said:

Or maybe I should buy a cheap second hand oven for garage use and for the sake of peace ..

Click to expand...

I've considered this, but my wife is decent enough to take the kids out for the day - her timing is usually spot-on :mrgreen:

If you are looking for more compression, this isn't the place.

Although this is a low pressure area (crankcase pressure limited) it is however a high stress area(dealing with the force of the stroke). Their isn't a lot of surface area on the cases to just lay down some sealer, no matter how good it is, and just ride on into the sunset. If you go gasketless, you better make sure that the mating surfaces are perfect and that they kiss up to each other without the slightest deviation. Short of removing the studs and some how lapping the surfaces together which would perhaps require resleeving, just go with a good fresh gasket and spray both side with Permatex spray on copper coat. Torque to spec and THEN ride on into the sunset.

I grant you, some have had success without a gasket, but really, if you plan on tearing down after every race you paticapate in, then maybe going without a gasket holds some merit, otherwise, don't go there.

In answer to you question, God only knows what they were thinking back then, which today leave us with only common sence to figure it out.

Is that my final answer?

YES

Sold, I WILL use a base gasket.

Thanks for all the comments!

Never have, never will!!!

Seeley920 said:

Never have, never will!!!

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+1

Never a weep.

pvisseriii, I'm sorry I misunderstood yout inquire thinking you
meant Base Plate,
AS it it Incomprehensible to me that AnyOne With much
time in Commandos would Even ask about or Consider putting
a crushable spring mooshing gasket under the cylinder
unless paid good money too on someones Else's bike.
You're call but never more for me.

On this subject there is only one place Norton engine even needs
a gasket - TS case cover, and that's not for its sealing
aid but only to space oil pump case seal.
Not even the head, but that

hobot

Not an argument, just a forum for opinion. Highdesert may do as he pleases, as You and I do
I have had jugs off many time and as Incomprehensible as it may be to you, I will never concider NOT using a base GASKET. Unless I want it to leak. Again, just an opinion base on my experiences.
In addition, I do have a compression plate sandwiched between 2 base gaskets and would not concider doing it any other way.

79x100,
I agree with all of your comments except for the last one about the through bolts going slack because they can't be re-torqued. The 5/16" and the 3/8" studs probably couldn't begin to take over the clamping force on the cylinder. The former because of their size and the later because it's anchored to an unsupported finger in the case. I think they function more for sealing than clamping, it's just that they couldn't hope to hold things together on their own. So if you use a gasket and it takes a crush after the engine's run in, the bolts loosen up some, the studs float a little, and whatever equilibrium you end up with is what you get. Most of the time it's sufficient. Personally, I've gone over to leaving the gasket out. When I did use gaskets I found that if I let the cylinder sit overnight or a few days I could re-torque all the fasteners and get around 1/8 turn out of them.
To go from the sublime to the ridiculous, those allenbolts might have been better off with a waisted design meant to stretch?

Leaked with a gasket. Rebuilt without and used Locktite Plastic Gasket, no leak. I'll never use another base gasket.

No gasket, Permatex ultimate grey moto-seal and a lot of care installing the barrel with a long pipe cleaner inserted in the barrel drainhole/crankcase drain hole, removing pipe cleaner after barrel is seated. Then run two more pipe cleaners moistened with lacquer thinner up/down drain hole, followed by compressed air from crankcase side. The Norton tech sheets explain that, as noted earlier, the gasket was reintroduced because shop mechanics were careless with sealer, blocking the (IMHO badly designed and too small) intake rocker box oil drain.

http://www.permatex.com/products/Automo ... r_Grey.htm

Ron L said:

Seeley920 said:

Never have, never will!!!

Click to expand...

+1

Never a weep.

Click to expand...

+2
If an engine comes apart in my shop with a base gasket, a new one isn't going back in. Just a light smear of Permatex Ultra Grey is all it takes, and that joint never leaks.

I've repeated this description before...Permatex or gasket sealer should be applied so thin that if you were spreading it on newsprint, you should be able to read the text through the sealer.

Just bored so only cluttering list in this banter >
as the data to use or not a base gasket has been covered above.
I won't no more unless just to say its factory restore down to the
worst weeping wart.

As to British or rather English manufacturers knowing how to
do it right they were the fountain head for most of the
best we got now, engine types to sealing and running em
to extremes.

But Gov't and Banksters and Shysters snuck in -
tooling not re-newed profits siphoned off and biggest
CEO of gasket manufacture in post war was convicted 6 yr ago
for criminally substituting any trash bulk material he
could in the whole range of gaskets, cars bikes,
home appliances.

Hylomar was a Rolls Royce developed product, they
sold it off for a train of sellers with some gaps in
availability , last one just a few years ago, until
Permatex took up the formula for us and rest of world.

In summary there is only One Place any gasket is
needed any where in Nortons, gear box to engine
and that as a spacer not sealer for TS cover - oil pump nipple.
Amal float gasket is second place a gasket is good idea.
Best head seal is sans gasket with wire in groove or
just Hylomar and good fit and hi torque.

hobot

Fitting a base gasket reduces the compression by around half a ratio I believe, so that could help to give the 850 MkIII's starter motor (and especially the sprag clutch) a slightly easier time? I've always had a base gasket on my MkIII and it's never leaked.

L.A.B. said:

Fitting a base gasket reduces the compression by around half a ratio I believe, so that could help to give the 850 MkIII's starter motor (and especially the sprag clutch) a slightly easier time? I've always had a base gasket on my MkIII and it's never leaked.

Click to expand...

The 880 that I built and did a proper CC check there was 1/4 point change with a gasket.