Exhaust studs

[elbrownos]

I'm going to be putting stainless downpipes on soon due to a holey collector. The Fazer's getting louder every day.
While I'm at it, I figure I'll change the exhaust studs to stainless too, so as to avoid any future troubles with snapping studs etc..
Not too keen on paying $$$ for studs so I'll get a length of M6 threaded stainless bar from Toolstation for £2 and cut it to length.
Any reason not to do this?
What length should the studs be?

Cheers

[AdieR]

Not sure what length they are, if you can get one out simply use it as a guide for cutting.

Beware, however, that stainless may not be the magical answer you're looking for - it can be just as reluctant to come out, and esp when they've been exposed to heat; I'd still use a little copper grease.

Some patience and extreme care will help you get the old ones out, plenty WD40 and possibly some (careful) use of heat is useful too.

[Fazerider]

The first time I took the downpipes off several studs came out rather than part company with the rusted remains of the nut and one sheared, fortunately leaving enough meat to get my trusty mole grips (the bodger's friend) onto. Those I replaced with stainless threaded rod cut to length (about 50mm from memory). The rest I didn't bother to disturb in case my luck ran out and one sheared flush.
I replaced all the nuts with stainless dome nuts (stuffed with copperslip)... never had any difficulty since.

[Fuzzy]

When I did my downpipes I seem to remember coming to the conclusion that ss studs were not a good idea because they can be prone to seizing with the aluminium engine block in some sort of chemical reaction between the two materials. Also recall hearing of reports of them being more brittle and therefore more prone to snapping.

Might worth keeping that in mind ff you go ahead with them - be sure to use plenty of copper grease and use caution when tightening.

[Fazerider]

I've never come across a problem with stainless steel with aluminium.
Even if that did happen it probably wouldn't matter in this application: generally when taking the downpipes off you want the nut to come off the stud, not the stud to come out of the engine.
It is important to use differing grades of stainless if you're using it for both nuts and studs... if they're identical they can weld themselves as the nut is tightened. I use A4 for the studs and A2 for the nuts.

[elbrownos]

Thanks guys. I ordered Motad Venom downpipes today so will be doing the job soon.
Already tried some of the nuts and they weren't seized so I'm not expecting too much drama.

[simonm]

I've never come across a problem with stainless steel with aluminium.
Even if that did happen it probably wouldn't matter in this application: generally when taking the downpipes off you want the nut to come off the stud, not the stud to come out of the engine.
It is important to use differing grades of stainless if you're using it for both nuts and studs... if they're identical they can weld themselves as the nut is tightened. I use A4 for the studs and A2 for the nuts.

Sounds like a damn fine idea.  Great thinking.  Have you taken the dome nuts off since ?

[Dead Eye]

Reminds me - I need to take all the nuts off and re-pack them full of copper grease just to make sure they don't seize

[Fazerider]

[quote author=Fazerider link=topic=7616.msg74067#msg74067 date=1367828484]
I've never come across a problem with stainless steel with aluminium.
Even if that did happen it probably wouldn't matter in this application: generally when taking the downpipes off you want the nut to come off the stud, not the stud to come out of the engine.
It is important to use differing grades of stainless if you're using it for both nuts and studs... if they're identical they can weld themselves as the nut is tightened. I use A4 for the studs and A2 for the nuts.

Sounds like a damn fine idea.  Great thinking.  Have you taken the dome nuts off since ?
[/quote]
Yes, after being untouched for three years of all-weather riding (including plenty of well salted winter roads), the nuts undo easily.

[Fuzzy]

That's good to know. Heard copper nuts are good for stainless studs too. Not sure if already mentioned and most will probably know already, but also make sure that the end of the stud is covered by the nut, double up with nuts if necessary. Keeps the muck/corrosion off the threads so the nuts can come off with ease, that's the idea anyway.

[elbrownos]

I'm just going to use stainless long nuts (actually stud connectors) on stainless studs, with copper grease both ends. Galling won't be an issue at 10Nm

[Dead Eye]

I'm just going to use stainless long nuts (actually stud connectors) on stainless studs, with copper grease both ends. Galling won't be an issue at 10Nm

If you go that route, get some washers as well. I have the same nuts (connectors) but they are slightly too small so the flange begins to deform / eat the edge of the nut

[limax2]

Heard copper nuts are good for stainless studs too.

Brass nuts are often used for exhaust applications. I've not come across copper nuts being used (I could be wrong of course) and I'm not sure that the thread in a copper nut would be strong enough. 

[elbrownos]

Copper nuts would be as much use as a chocolate teapot.
Brass nuts are often used with stainless studs/bolts to avoid galling

[Fuzzy]

Sorry, should have said copper plated nuts. Some oem exhaust nuts are copper plated but perhaps brass nuts are easier to get hold of, I don't know.