Hi all, need input/opinions.. I'm trying to do a clutch spline lube and a clutch friction plate thickness check/replacement before heading off into Europe in the second half of June. and after watching Chris Harris make the whole thing look easy I've got as far as trying to get the exhaust off. This is taking some time.. Basically, I've undone the four clips where the individual, umm, downpipes (??) go into the collector/muffler but for the life of me I can't get the muffler to come off the end of these pipes, even with hammering a bit of wood pressed against it. I don't really want to do anything more abusive to it.

So I looked into taking the exhaust off the engine, like our lord and saviour Harris claims is easier, but I have a problem that he didn't seem to encounter - serious rust. The nuts are no longer nut shaped, after scraping a spanner around them they are just round bits of rust stuck on to the studs:



But the clamps do surely look like they need replacing, they seem quite warped. So if I hammer a socket on to these, does anyone reckon the studs might turn out? Or are they likely to snap? I don't want to scupper myself like that with so little time to go. And if touching these is dangerous, does anyone have any tips for getting the muffler off?

Otherwise, this job is just a nightmare, balancing the bike on bricks and wood so I can take the stand off is crazy, and I can't get one of the bolts out of the bottom mounting of the Z rail and the exhaust side because it's stuck in the footpeg bracket, and I've barely even started yet!

My .02:

You're best off leaving the exhaust headers (the four pipes from the cylinder head) attached to the exhaust can and removing the exhaust as a whole. Getting those aligned and reinstalled into the exhaust can is a royal pain.

For the rounded header flange nuts I'd use a 12mm deep well bolt extractor on those. BEFORE you attempt to remove them saturate them in penetrating oil and let them sit for 24 hours (or whatever it recommends on the can.) Using a propane torch on them before you try to remove them won't hurt either.

If the studs come out of the cylinder head it's not a big deal.

Use a lot of good penetrating oil (not WD40!) before.
A few slaps on the top of the nuts before will help to unscrew.
Heat the engine before.
Hate me for giving this advice when you burn your forearms on the exhaust pipes.
There's few chance of snapping the studs. As they are threaded into aluminium, usually the nuts are seized on the studs, but they both unscrew easily from the head.
But...not always. Shit happen
If so, then start again from the beginning.
You may find comfortable to lean the bike on the right side to proceed more easily.
If there's enough material, weld a bigger screw on the remains of the stud.
If not, then cut it neat, drill at the center and use a counterwise screw extractor.
I had once to remove 3 snapped studs on a K1100 with a side car.
I spent 3 days laid under the engine. I had to drill into each stud with a 2mm drill, then 3, then 4, then 5, then remove the threads...But eventually I managed to install new studs.

Use lots of penetrating oil(not WD40) and let them sit at least 24 hours.  DO NOT use a 12 point socket.  Get a deep 6 point impact socket.  6 point sockets will not round off the nuts as readily as a 12 point because they have more contact area on the flats(or what remains of them) of the nut.

Clean the threads of the stud as much as possible and heat the nut good and hot with a torch before attempting to loosen it.  If you can get an impact gun it will help a lot. 

Try to move the nut a little in the direction to tighten before you attempt to loosen it.

When you get them out, it is not a bad idea to replace them with new stainless studs and stainless nuts which you should be able to get at a well stocked industrial hardware business.  In the states I get them online from McMaster Carr.  Put anti seize on them so you or the next owner won't have this little bit of fun.

Before you go in make sure to have new studs, nuts and crush washers. 

Honda studs and nuts fit too.....

get a stud extractor on the nuts , cheap kit on ebay , tap with a hammer and the studs will come out , throw away and replace , this is a very common problem , the silencer will not come off with the down pipes fitted tight  and if you hammer to much you will snap a stud

Thanks guys, I have bought a cheap set of extractors and will be spraying the lot with penetrating fluid, though I've never known it help with exhausts before now.

Are people running stainless studs and nuts? Have you had any trouble with them coming undone? This is usually the problem I have until some rust starts to hold things in place..

As for a 12 sided socket rounding off the nut, the nuts are already round. They're hardly even nuts any more. At first they looked like this:



But after putting a 14mm spanner on them, the outside just came off in dust/bits. The same then happened with a 12mm. They're about 11mm now, and round. There actually doesn't seem to be much nut keeping the clamps in place..

I also wanted to remove the downpipes from the muffler so that I could replace one of those clamps, as it looks to be splitting:



Once the exhaust is unbolted from the engine, am I alright to mark the joint and then remove the pipe? Or is the whole thing just a complete nightmare and I should consider it now a one piece system, while hoping the rusty engine-side clamps last and this muffler clamp is just bluffing?

Jack: the problem with the silencer is that it is glued to the downpipes with carbon and fuel deposits. I had one like that and eventually got it off by lots of penetrating fluid (Kroil), heat and - grabbing the damn thing at the back and yanking it from side to side. Once it started to show a bit of movement, I then switched to rotating it. It took a few hours of heat, Kroil and rotate...!

Regarding the studs: again, I've faced the same problem. Heat, GT85 and hammering the sh!t out of a hex-sided 11mm deep socket. 'Side drive' type sockets are best. One exhaust was so glued into the head that I ended up using a two-foot piece of pipe for extra leverage to get it moving sideways. It didn't stay glued for long after that. Stainless is fine. I ran an 8mm bottoming tap up the threads to clean them out before fitting the new studs. Don't use copaslip when you replace them because in my experience across quite a few bikes, the times I have done that has led to the copaslip burning and acting as a really good glue.

If absolutely nothing looks like coming out, Dremel the collars into small pieces.

Oh - and bugger the clamps. They're a damn nuisance to line up and clamp up anyway. I've left them off all three of my bikes and there's no real signs of carbon blowing forwards, nor is the exhaust any louder.

A twelve sided socket is a bad idea for any bolt or nut.

I have put stainless studs, nut and lock washers on several of the bikes that have found themselves in my garage.  They have been on my RT for over 8 yeras and 40,000 miles and still look good like new.  The nuts have been off a couple times since then with no issues.

I like a little anti seize on stainless to prevent galling of the threads.  So far, I've had no issues with hardware not coming apart when it needs to.

"In the states I get them online from McMaster Carr."


Do you have links and part numbers for quick lookup SVP?  ;-)

Bricklayer"In the states I get them online from McMaster Carr."

Do you have links and part numbers for quick lookup SVP?  ;-)

https://www.mcmaster.com/products/threaded-rods/system-of-measurement~metric/thread-size~m8/thread-pitch~1-25-mm/length~40mm/material~stainless-steel/

Super- thanks! Needed the size so I am good to go.

Update!

Today the extractors arrived, mmmmm:



A few taps of the hammer and the first one at the front was off!



3 out of 8 came out like this. The rest were so badly corroded that the 10mm extractor just span around them, so I took to hammering on a 9mm socket instead. This worked, although it was a bit of a faff.



Overall, this really wasn't so bad - the nuts weren't that tight, I just couldn't grip them properly, and the studs aren't that tight either since the two that came out didn't click or fight. Once they started to turn, they came out.

After a bit more encouragement the clamps have come off the remaining studs, and I'm now left with 4 exhaust pipes that seem to be absolutely welded into the head. Am I okay to be levering wood against the rocker cover to try and get these pipes to come away? It all feels very brutal. It also doesn't help that the bike is somewhat unstable on the bricks, I should have done the exhaust while it was on the stand with both wheels attached..!

Never seen this type of socket before. Presumably designed to fit corroded mis shaped nuts. What is it called?

JGT wrote:
Never seen this type of socket before. Presumably designed to fit corroded mis shaped nuts. What is it called?

Irwin brand name is Bolt Grip but the generic name is bolt extractor. Like an easy-out but for bolts/nuts instead of screws.

Snod Blatter wrote:It also doesn't help that the bike is somewhat unstable on the bricks, I should have done the exhaust while it was on the stand with both wheels attached..!

I use a sawhorse when doing spline lubes. Keeps the bike very stable.

You did well there Snod. Those manifold studs and bolts are the bane of my life! I've drilled out many over the years. 

I have a set of Kamasa brand sockets i bought about 30 years ago which grip the face of bolts and not the corners. They have proved their worth over and over again. I have also used a welder and stick a rod to the tip of the stud to send heat down it to good effect. Replace everything whilst you are in there and copper grease the eff out of everything for the next time you have to go in there. It's gratifying to see a new suite all bolted up on fresh crush washers .

Nickel based anti-seize holds up under higher temps than copper based anti-seize.

88 wrote:You did well there Snod. Those manifold studs and bolts are the bane of my life! I've drilled out many over the years.

At least you said this afterwards, otherwise I would've been even more scared of doing it..

Anyway, update! Basically removing an exhaust from a rusty K is an absolute nightmare. If #1 cylinder is at the front then #4 is easy because you can hammer it downwards with a bit of wood as an extension. #3 can be mostly shifted this way too if you can find some wood thin enough to fit through the gap but strong enough to take the hammering. The front two cannot be hammered though. After some wrestling and levering and desperate heat gunning with more levering, this happened..

Sorry old girl but a pole up yer jacksy seemed like the only way. After MUCH heaving on the pole there was a couple of almighty bangs and some dust expelled. And then, after some more wiggling up and down, each time being able to go a little further.. It damn near fell off.

I'm not sure if this is what Dai means by levering it with a pole but it worked for me. After this outright abuse I could only laugh at the way the pipes were still perfectly attached to the silencer, what on Earth are the clamps on there for?? None of it has shifted at all.

After removing the exhaust clamps from the head I could also see a lot of the "collar" around #1 has been broken off at some point, here it is on the left - the blue parts are actually where it is broken off. It was really hard to get a picture that obviously shows it's missing, but it is - up close you can see the copper gasket is actually proud of the surroundings. But it doesn't blow, so whatever.

So this may be at least part of why mine was so reluctant to come out. But it did! And I don't think I broke anything other than nuts that were barely nuts any more.

Nickel grease is interesting, I'll have to see if I can get a small amount for a reasonable cost.

Also, I don't really want to disturb the studs that are still in the head in case one snaps off. Is it really standard practise to replace them all with stainless if you're at this stage? There's nothing wrong with them..

Oh and the big nut on the left side of the swingarm has also undone, as have the three little ones on the right. Are there any more showstoppers from here? I hope not. And I plan to use Castrol Moly T/A stuff to lube the clutch splines, all speak up now if this is considered heresy..!

this can be a problem with such a relyable bike , lack of maintainance , if the down pipes are as solid as some you maywant to look for another system , you will damage either the down pipes or the silencer trying to seperate them unless you have access to some extreme heat (oxy/actet bottles will be required)   or cut and grind the silencer off and buy a replacement , the down pipes are expensive , on the up side its off 

For the future...it's usually fairly easy to get the studs to spin out (tho' you have so much more typical corrosion over there as compared to sunnier, drier climes) by attaching double nuts to the threads. The nuts are 8mmx1.25 pitch, and the studs are 8x40mm. If you're skint get some threaded rod, cut it to length then run an 8x1.25 die carefully onto the cut end, improving the threads where you cut the rod. Heat-resistant paste keeps 'em all together but more easily removable later on. Replace the four 32x40 crushable metal collars set into the head, BMW part number 11 62 7 662 083 if you have a dealership nearby, or Motorworks, or the boys at the 'Bins.

If OEM is preferred:

11 62 7 662 083 x 4 gasket rings
11 62 1 744 322 x 8 nuts
07 12 9 908 133 x 8 (or 07 12 9 903 964) 8x40 studs

Snod Blatter wrote:I'm not sure if this is what Dai means by levering it with a pole but it worked for me.

Nah, not quite. I meant the silencer alone to separate it from the exhaust pipes. The other problem I had on that bike was that I got the silencer off but the rear exhaust pipe was not coming out. I soaked it with Kroil and then when it still wouldn't move, slid a just-fitting steam pipe (!!) over the exhaust and started pulling it sideways. I figured the worst damage I was likely to do was to bend the exhaust pipe, rather than a vicious up-and-down action which could have damaged the cylinder head.

I'm also betting that your 'blue bits' are carbon depositis caused by blow-by.

It certainly was vicious but I can't see how I could be any less vicious getting the muffler off!

(silencer is the correct word but I couldn't think of it at the time, nuts)

It's not blue in real life, just road dirt black, and there are no "blast" marks from soot or anything. Even more amusing is that this is a replacement engine fitted by, I think, James Sherlock so they thought it was perfectly acceptable.. Or at least the customer would never notice!

Snod Blatter wrote:James 'Ripoff' Sherlock

FTFY. I can't see how the hell he justifies his prices - oftem more than twice what Motorworks want for the same item.