Exhaust nuts/studs
 

I always have trouble with exhausts studs rusting then breaking when I try to remove the exhaust on my XT, even after replacing with new genuine studs and nuts 6 months later a stud will snap when I try to remove the exhaust.
I have just seen a Honda XL600 that had chrome domed nuts on the exhaust studs. They looked like 8mm XT is 6mm stud.
Do you think domed nuts would help ?
Is it possible to fit 8mm studs in the XT600 with out causing other problems.
What would be the best studs to use?

I had similar trouble recently....Two of the four snapped and one of the snapped ones had to be drilled out. I upsized that one to 8mm without problem. Even though I fitted a stainless header, I still intend to re-apply copper grease once a year, but hope the exhaust will outlast the bike now!

DC:thumbup1:

My Yamaha dealer tried to remove the factory exhaust, because it had holes in it. It took them 12 hours of labour because all 4 studs just snapped. They used burners and whatnot to take the exhaust pipes off. Then they put it all together again, stainless pipes and such, and then we discovered they dropped a piece of metal in the cylinder... They paid for the entire repair. Now I take the pipes off every month, just to be sure.
Stainless and aluminium just isn't a good combo.
My advise: don't use an XT in wet, muddy conditions. :D:Beach:

Good advice...But dont think your troubles are over if you slacken the studs now and then. The problem I had was that the 'shoulders' on the exhaust remained tight against the engine in their sockets as the old exhaust was rotten. Access to remove them was difficult and it took a weekend of swearing to get them out of the block.

DC

Brass nuts might work better than steel as they ought to fail before you can apply enough torque to break the studs. However, the only brass nuts i've found have been no more than 5mm depth.

"However, the only brass nuts i've found have been no more than 5mm depth."
Bigger ones I've never had a problem getting, but usually from a car parts place.
firewall forward

But isn't there something about brass nuts and cold weather?

studs
 

My answer to this is to just make the brass nuts any size that I want. I can do that as I have a pretty complete maching shop but if you bought brass stock in hex of the size that you needed any machine shop could cut them and thread them on a lathe with a tap for little money. At least compared to 12 hours of cussing and swearing and wrecked blocks and things.

If you mean the saying "cold enough to freeze the balls of a brass monkey" then this refers to the fact that brass will contract a lot more during cooling than steel - so could potentially damage the stud?

I replaced my studs with stainless steel nuts and bolts with the heads sawn off. Due to the heat and exposure the original nuts had rusted firmly onto the stud causing the stud to either release itself entirely from the head or snap. Stainless steel with liberal doses of copra slip and the problem of magnesium to steel and steel to steel oxidation has gone......touch wood.

I've jinxed myself now havent I. Bugger.

Stainless studs and nuts sounds like the best way....but....stainless will heat-weld itself together if given half a chance.Overall the best combination is stainless studs and brass nuts,and i've never failed to get those undone when needed.As for brass contracting more than steel in cold climates,the tollerances between stud and nut are more than enough to compensate for this so don't worry about it.Brass nuts are available off the shelf in m5,m6,m8 and m10, Screwfix.com - Where the Trade Buys stock them.
As far as getting the original siezed nuts undone,soak in WD40 or similar for a few hours and if they don't move with a gentle try then don't heave on them! Get hold of a small drill bit ( about 2-3mm) in a drill and carefully drill a couple of holes into the flat side of the nut until you get down to the stud underneath,then using a sharp chisel,split the nut and remove.This way you stand half a chance of having a usable stud remaining to thread a new nut onto.

I dont know how this would work on an exhaust stud, but it works great on turbine engine bolts that are exposed to high heat.

From:Fastener Design Manual -- part one

Silver Plating Silver plating is cost prohibitive for most fastener applications. The big exception is in the aerospace industry, where silver-plated nuts are used on stainless steel bolts. The silver serves both as corrosion deterrent and dry lubricant. Silver plating can be used to 1600 F, and thus it is a good high-temperature lubricant. Since silver tarnishes from normal atmospheric exposure, the silver-plated nuts are commonly coated with clear wax to prevent tarnishing. Wax is a good room-temperature lubricant. Therefore, the normal "dry torque" values of the torque tables should be reduced by 50 percent to allow for this lubricant.