Exhaust Header Nutz

Decided to remove the down pipes and pretzel as Mr Roper calls it, luv using his terms as baffles my mates
To facilitate getting the down pipes professionally polished prior to fitting my new Mistral Shorty that's due very soon.
Noticed inner flanged nuts were rusted to f*ck and only 10mm? outer nuts looked to have been replaced as were not flanged and were 13mm?
Obviously stud size is identical least I imagine it is? as had to shift my arse sharpish for another engagement.
Was concerned as f*ck as thought the studs might snap off, but after nut removal studs seemed quite healthy
Intend to use some stainless domed nuts to keep the rust out when refit them.
Would consider fitting some stainless studs too as there are kits available on Gutsibits for other guzzi's.

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Use brass nuts with some neverseize on them - they will not bind like steel and stainless nuts. You might be lucky and get chrome or nickel plated ones - dome nuts too.

Or just make some from brass hex bar...

Oz1200Guzzi wrote:

Use brass nuts with some neverseize on them - they will not bind like steel and stainless nuts. You might be lucky and get chrome or nickel plated ones - dome nuts too.

Or just make some from brass hex bar...

Found that silver molycote stuff all over the bike, though non on the head nut studs, pity
So nut size 10mm or 13mm?

I put stainless steel studs and stainless lock nuts on my Cali 1400 a few years back.  Suffered severe galling.  Here's an article about galling.  

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The nuts were stuck on to the studs, and I could not undo them, just unscrewed them from the heads.

Even then placing the studs in a vice and winding the vice up real tight, and using a long bar driving a 10mm socket wouldn't separate them.

Proceed at your peril!

kiwi dave wrote:

I put stainless steel studs and stainless lock nuts on my Cali 1400 a few years back.  Suffered severe galling.  Here's an article about galling.  

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The nuts were stuck on to the studs, and I could not undo them, just unscrewed them from the heads.

Even then placing the studs in a vice and winding the vice up real tight, and using a long bar driving a 10mm socket wouldn't separate them.

Proceed at your peril!

Hence the moly coat if I was to use stainless on stainless studs or even stainless dome nuts on the steel ones. Stuff is designed for use on head bolts.
I've never suffered galling and been using stainless on stainless for decades.
Did you use moly coat or any form of anti seize paste?
Did you torque them down or just wang them up tight?

I just described my experience with stainless on stainless.

I repeat do it at your peril.

Brass exhaust nuts are common and work well.
Because they are used on all sorts of vehicles they are cheap Linky to Ebay = 12 nuts at £4.99

you can get (cheaper) copper flashed nuts but the copper surface can be penetrated on assembly - brass is safer.

The nut head size is not an issue just get the right thread - i think it is 8mm x 1.25 mm but you should check before purchase

I'm not familiar with "molycote", but it seems you're describing an anti-seize compound. If so, DON'T use silver. Those tiny silver flakes are nickel, the same element that make stainless, well, stainless. Use the copper based compound, widely known as "high heat" anti-seize.

lcjohnny wrote:

Brass exhaust nuts are common and work well.
The nut head size is not an issue just get the right thread - i think it is 8mm x 1.25 mm but you should check before purchase

It is correct checked the parts manual, only difference is the originals are capped so had to avoid ebay. Ordered both regular and capped just in case.
I can't say have ever heard about the galling issue though have seen plenty of nuts rusted to studs whereby the studs extracted instead of the nuts.

Stainless on stainless and tightened up. Add multiple heat cycles - what on earth could go wrong. It will.

Oz1200Guzzi wrote:

Stainless on stainless and tightened up. Add multiple heat cycles - what on earth could go wrong. It will.

Ok Ok O-k--a---y, might be stainless cap head on regular steel, then when the headers bronze up swap to brass on steel?

Stay away from stainless steel for this application.

I repeat again (to infinity), do it at your peril.

I'm thankful to have never experienced these troubles.

Steak wrote:

I'm thankful to have never experienced these troubles.

Neither have I ever and used stainless nuts and bolts on lots of jap multi exhaust studs/mounting holes.
That said because the fittings themselves are so durable I've also never removed them after fitting them.
As usually got bored of the bike and moved it on

On the GRiSO because I may well remove the headers again at some point am inclined to go with what the old fellas suggest

Cleaned up the steel studs and lubed them with Copaslip as it's anti seize to well over a 1000c
Ran a nut up and down by hand to ensure was a smooth action.
Aquired some brass manifold locking nuts so hopefully this will apease the old codgers

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By the way, it's not nutz, it's nuts. Just being pedantic with the English language.

Oz1200Guzzi wrote:

By the way, it's not nutz, it's nuts. Just being pedantic with the English language.

Actually the reason for typing Nutz was because was two different head sizes, so reason in the madness

@buellbloke they look like copper flashed nuts. As long as the copper does not scrape through they should be as good as the brass.

The problem is that the spray arriving on the exhaust will be saline (very saline in winter).


The force of electrochemical corrosion between metals depends on the electrochemical potential between the two metals.

So you want a non ferrous nut with the lowest electrochemical potential to steel.

lcjohnny wrote:

@buellbloke they look like copper flashed nuts. As long as the copper does not scrape through they should be as good as the brass.

The problem is that the spray arriving on the exhaust will be saline (very saline in winter).


The force of  electrochemical corrosion between metals depends on the electrochemical potential between the two metals.

So you want a non ferrous nut with the lowest electrochemical potential to steel.

Went to my local stainless supplier, they told me they were brass, f*ckers
They do look like copper, guess they will be suprised when I take them back
I dont know about you johnny but I dont ride in the rain, occassionally get caught out in summer rain but its rare.
Obviously ride through the odd salty puddle though this time of year no doubt.
I did have problems sourcing locking brass manifold nuts online so was surprised when they came out with these

If they stick to a magnet, take them back.

My nuts are rusty, and I don't care.

Rusty Nuts, or not.

As winter is pushing it's way into the US Mid West I'll probably be visiting my exhaust headers in the coming months.

If brass nuts are what you're looking for then I suggest a supplier like Bell Metric. Easy to remember, BellMetric.com and search for your particular bits. Bell Metric carries Brass Nuts in M8x1.5 at $0.63 each and M8x1.0 at $1.09 each. These guys are a no BS supplier of esoteric hardware here in the States. The other place I may look for odd hardware would be McMaster-Carr. They don't show any Brass Nuts but have Bronze Nuts at $8.39 for a pkg of 5 in the M8x1.25.

As far as Molykote, that's a brand name of coatings from DuPont. I believe we used to use the Molykote G-N on the exhaust parts of Pratt Whitney 4000 series exhaust bits. We used this other stuff by the name of Silver Goop, no shit real silver, for the Rolls Royce engines.

So, don't get your nuts in a bunch. Quality hardware and coatings are available. Maybe just not Guzzi owner cheap.

Obviously on boats virtually all fastenings are 316 stainless steel. Galling is a real problem without
a lube coating. Tef-Gel is the product we used on race boats and superyachts. You won't have galling is you lube the threads with it.
Copaslip and brass nuts are best for the headers  I don't think Tef-Gel would take the heat.

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Titanium is fairly inert, right? That work for said nuts nutz?

Westfield fasteners, simply bearings etc in UK.....like these (not sure what pitch you need)

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Thanx for all your help peeps but think am on the ball with fastners as one of the cheapest upgrades you can buy for your GRiSO, any bike for that matter.
Most of the fastners already fitted are in stainless from what I've encountered.
Except the rear mudguard and front belt guard which were rusted to f*ck.
I hear peeps complaining about water ingress around the fuel cap and rusting bolts mine are stainless.
The only ones to avoid changing seem to be the tapered ones used to mount the Becker stand as regular bolts wont fit.
Only brass fittings I failed to secure were split locking washers, maybe they are too soft for the job or too brittle.
Not even sure to use them split washers as normally head studs/nuts arent secured except for gasket pressure and torque.
I could always use the regular brass nuts and lock the brass capped nuts up against them effectively blocking water ingress from the front?

Checked all my new brass fittings pictured with a neodynium magnet and non are attracted, though not the so called brass locking nuts as these are up the garage.

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