I looked around the forum a bit, but couldn't find anything specific to what I need.

Well, the exhaust on my '92 k100rs is cracking where the pipes are welded to the muffler.  I've welded them a couple times, but I'm missing the mount for that middle section where the box/bulge is (the catalytic converter?).

My question is: Will the exhaust system from the older K100s (the square shaped ones with the heat shield on them) fit my bike?  Will I need to fabricate a mount for the middle section and the back? I believe the headers fit just fine, correct?  I also remember this exhaust to sound quieter than mine, which is a plus.

If that is not an option, what aftermarket exhaust systems would work, and provide a quieter sound than the stock exhaust system?  The quieter the better.

Thanks!

I have just replaced the continuously cracking system on my K1100 with a set of K100 header pipes and a staintune muffler for a K100.  The rear mount was a problem for me but the mount for the 16v K100 is more suited for you. The staintune is louder than OEM but to me acceptable but on the upper limit. I think the square K100 muffler would fit but I am not 100% sure.
TWB has a Motad mufler on his K100RS and it is a far more acceptable note than the staintune and a lot cheaper.

So you took the pipes/headers from, let's say, a mid-80's k100, and then connected in an aftermarket exhaust?  It seems that the rear mount is the only problem that would be run in to?, and that's an easy fix.

Yep thats right. The K1100 has a different mount on the muffler than the K100 8v the mufler was designed for.
The 16v K100 mufler does have the same mount as the K1100 so you will have to make a mount but when I made a mount it wasnt a big job.

Bear in mind that the early Ks had a '2 hole' muffler mounting with a different footrest plate to the later '1 hole' system. The single hole fixing bracket is available from Motobins.

Paul.

Paul, you are referring to the rear mounting bracket, correct?

Yes, this is the single hole mounting bracket which bolts directly to the footrest plate.

 The two hole mounting has rubber bushes in the footrest plate.


 

Paul.

I am using the Motad system, as RickG suggests, and it is quiet, but not quieter than stock. However, it's not loud and is EU noise limit registered. I reckon its sound is different from stock, less vacuum-cleaner-with-a-headcold, more low down burble.

The 160mm tyre will come pretty close to it on a 16V model, but the unit will fit, and it's a round end can. Get 'em directly from Motad UK or off eBay. I paid about $350 delivered to OZ several years back.

I agree with TWB, I had a Motad slip-on system on my RT and the sound was spot-on, not too noisey at all and it seemed to give a little kick around 3500 rpm.  But it doesn't increase engine output in any way overall.  It's a known fact that the stock BMW system is best in that regard.  From memory the Motad was about 4 kgs lighter though !  Nice system, well worth it.

I'll keep the motad in mind, seems like it would sound nice.  I like the idea of the low rumble.  I like the sound of the older 'square' pipe from the earlier Ks as well.  It's smoother sounding and quieter than mine as far as I can tell, and for some reason, I like the look as well.

Either way, I'll have to get the header pipes, right?, as my system currently is all one piece welded together.

I would think that the older square system would be a different sound to my round one as it is bolted to a 90 hp 8 valve engine, whereas mine is bolted to a 100 hp 16 valve engine. It is hard to compare the sounds without using the same engine for both systems.
The Motad looks great, but comes without headers, I am not sure that I want to remove my existing headers and try and make them fit the Motad can.

Just use header pipes from a K100 8V

RicK G wrote:Just use header pipes from a K100 8V

Rick are you saying that they are different? It is a long time (25 years) since I owned an 8v and can't remember.

Yeah the 8V have 4 seperate pipes thar join into a collector on the front of the muffler where the 16V have a one piece and you couldnt make them fit even by cutting them of the muffler part, they would be too short.
I have 8V pipes and a staintune muffler on my K1100.  The mount at the mufler needs a extension made for it but no big job.
The longer pipes have definately given it more grunt down low.

Thanks for that information Rick, I will have to look out for some 8v bits now.