Finally bit the bullet and fitted an Aussie made "Staintune" muffler today. When I removed the original muffler and header pipes (in one piece) I didn't see any copper washers/gaskets fall out of the exhaust port. When I fitted the new muffler and header pipes (about 10Kg lighter!!), I used the original copper(?) nuts and the original copper washers/gaskets (which I couldn't see)

Should these be replaced? Took the Yellow Beast for a 20Km jolly, up to 7½ - 8 thousand RPM at times, and the new system didn't miss a beat (ie, it didn't blow up!!) and it sounds GREAT!!

There didn't appear to be any gas/noise leakage at the exhaust ports.




Checked the LHS pannier and it still fits, with about 2" of clearance between the muffler and the bottom of the pannier.

Rickmeister,

New exhaust looking good. 

The copper header gaskets don't usually drop out - they end up getting distorted in place and become wedged in the exhaust ports (nearly indistinguishable from the port once they have that patina of combustion about them). When I have worked on the exhaust headers, I have always had to lever them out. The distortion (being soft copper and all) is what makes them seal and is usually why you have to replace them - once compressed once, you can't guarantee a good seal next time round. Having said that, if you have left them in place, the new exhaust is fitted and it's not leaking, it sounds like you've got away with it and saved yourself a few $AUS.

Likewise with he copper nuts - they often get trashed when removing them and it is worth replacing them - if you didn't trash them taking them off, then there is no reason why they can't be reused. The threads will stretch a bit when they are torqued up, but they are not under that much stress once they are all in place so are unlikely to fail.

Personally (as a graduate from the school of hard knocks and told-you-so, with a major in sod's law), I now keep a set of studs, nuts and copper gaskets in my come in handy spares drawer so that they are readily available if I need to drop the exhaust for any reason. Generally, I will always change the gaskets, usually the nuts and the studs only if I have to.

Where the hell did you get the exhaust? I thought these were no longer made.

looks great ulli ...

like wow

Nice looking exhaust.

Now, just to satisfy my curiosity, is there any reason not to replace the copper plated nuts with stainless?  The copper plated nuts rust and seize onto the studs making removal a pain.  I don't have that problem with stainless.  Not to mention that stainless is cheaper.

Nice one Ulli. I'd like one for my Old Girl. Is it new or did you buy it second hand?

I've had my headers off a few times and always apply a little anti-seize grease to the studs. I've never bothered to replace the nuts.

Looks great Ulli. This is the exhaust gone back to its original owner. I had it on the yellow beast but took it off before being sold. Fantastic job. Cheers.

Point-Seven-five wrote:Nice looking exhaust.

Now, just to satisfy my curiosity, is there any reason not to replace the copper plated nuts with stainless?  The copper plated nuts rust and seize onto the studs making removal a pain.  I don't have that problem with stainless.  Not to mention that stainless is cheaper.

And as I about to refit my exhaust with stainless studs & nut's I was interested to see your post and others on the same subject.
I had a set of steel studs with copper coated nuts, but then decided to try stainless.
I'm very glad to read it's not too much of an issue to re-install them and they don't have to be too tight, and to use copper grease and not loctite.

So hopefully  all things being equal, I'll get them on and get her finished in the next few days

Rod

Last set I replaced (six out of eight studs) I used stainless. I glued the engine end and taught the nut end to swim in copperslip. No problems yet.

Very good Dai,

 What did you glue 'em in with I wonder

Rod

Loctite 640, I think it was. I drove the studs in by the time-honoured method of locking two nuts together.

Sounds like a plan, though I'm not going to get tooo bothered with locking them in hard.
I like the double lock nut idea and was thinking along those lines also

Time will tell
R

That 's the stainless studs done, next is center stand

Looks like you've possibly got old gaskets stuck up in them there orifaces?

Before using stainless in an aluminum alloy head you might want to investigate the corrosion potential between stainless and aluminum.  Stainless is great stuff but not always the best solution.

I assume that whatever metal was chosen  for the factory header flange bolts and its corrosion potential was taken into consideration when the factory bolt metal was selected.

Duck, I've replaced a lot of fasteners with stainless on my bricks.  I always use copper grease with them, and so far in four years I have seen no adverse effects from their use. 

I used to work in a boatyard, and know the issues with using stainless in aluminum, but they are only bad in the presence of warm saltwater.  Electrolysis is very low in the presence of fresh water or low concentrations of salt water.

Point-Seven-five wrote:Duck, I've replaced a lot of fasteners with stainless on my bricks.  I always use copper grease with them, and so far in four years I have seen no adverse effects from their use. 

I used to work in a boatyard, and know the issues with using stainless in aluminum, but they are only bad in the presence of warm saltwater.  Electrolysis is very low in the presence of fresh water or low concentrations of salt water.

I always replace all of the visible hardware on my bikes with stainless too. Never had any issues and I only use anti-seize on ones that are typically hard to get out, like the front rotor bolts on 4Vs.  But those header flange bolts go through the most extreme heat cycling so I wasn't sure about those but what you say about the marine environment makes sense.

The threads that can tend to get corroded a lot even with factory steel HW are the four little bolts that hold the gas cap in the tank.  But those get removed relatively frequently to change the fuel filter and I don't torque those down very hard.  I also replace those with hex heads since the tiny Phillips heads on those like to strip if you're not careful.

I just had the headers off the Big Block for a four-into-one collector weld-up repair and was able to successfully re-use the OEM copper nuts (with anti-seize) and the exhaust port seals, all of which didn't have that many miles on them. I didn't bother to prise out the seals as they looked good enough to use again - and I've often re-used them on my other K bikes. I did see some telltale exhaust tracks down the two forward headers (which I cleaned up nicely with 600 grit) and after properly aligning the muffler, collector and the four headers (which I must not have done right the first time), this soot has disappeared. There never seemed to be an audible fahrt noise down there but hot gasses do have a way of finding an escape path in their journey out (pardon the pun). 

As for studs, once, when I was far away from being able to obtain the required length studs and needed to replace several corroded and not reusable strippies, I bought a length of threaded rod in 8mm x 1.25 and hacksawed it to length, ran an appropriately sized die over the cut ends and Bob's yer uncle.

A lot depends on the grade of ally: the softer the ally, the faster it will cause a mess with your stainless. There's nothing to worry about with the engine blocks. Now, putting stainless bolts through Givi Wingracks... there's a crap-pile waiting to be dumped.