BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


1Back to top Go down    Exhaust compatibility / change on Thu Dec 19, 2013 9:07 pm

Rabidchiwawa007

avatar
Platinum member
Platinum member
Hello all,

This is in regards to a 1992 k100 (motronic system, NOT L-Jetronic). My pipes keep cracking at the weld where the meet and go in to the muffler. The last time I took them off to re-weld them, they had almost fallen apart completely and were really only being held in place by the mounting system for the exhaust. I have an idea as to why this is happening: I believe it's due to the missing rubber mount support for the catalytic converter. I had attempted to create a brace, but that brace just broke in half from the vibration down there.

So the question: Would taking the catalytic converter out of the exhaust system make a huge difference in running? Good or bad? As far as I can tell, there is nothing there feeding the computer or anything. I would think it'd just get rid of a little back pressure, make it freer flowing, and thus make it run a little better. I'd like to get a different exhaust system altogether. I really like the stock square muffler from the older k100s. Would that be a viable option? What are some good aftermarket pipes / mufflers that would work with this bike?

Thanks in advance!


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

2Back to top Go down    Re: Exhaust compatibility / change on Thu Dec 19, 2013 9:20 pm

RicK G

avatar
VIP
VIP
My K1100 was cracking up for the same reason and I finally put the exhaust headers from a K100 and a stain tune muffler (second hand as I am too tight to buy a new one) and it is good now, a bonus is that the torque at the bottom end is much better due to the longer header pipes.
now I spend more time riding and no time fixing the cracks. I even put a new mount on the cat and they still cracked.
I was told that welding a flat bar across all 4 pipes where they leave the head fixes the problem but was not prepared to try anything else when I finally got the staintune.


__________________________________________________
If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

3Back to top Go down    Re: Exhaust compatibility / change on Thu Dec 19, 2013 9:32 pm

duck

avatar
Life time member
Life time member
To the best of my knowledge there's no cat in there. With the K1100s in 93 they went to a cat which is why the exhaust looks virtually identical but the K1100 has an O2 sensor installed for the cat. (If you check out the 93 K1100LT marketing lit for the US it mentions that the 93 K1100 is the first cat'd bike to come out in the US.)

So, what the heck is in the big box under the tranny on a K100RS4V? Got me.

JMHO but the best thing you can do is get rid of the factory exhaust and replace it with a Staintune or Remus. They will both save some weight and simplify maintenance. And they don't crack were the headers meet the collector.

All of the Staintune and Remus exhausts I've had my hands on have had a bung hole for the O2 sensor. When I ran a Staintune on my 91/92 K100RS I just had a plug in there.

Disclaimer: This is my knowledge regarding US bikes. Not all countries had cat'd K1100s.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

4Back to top Go down    Re: Exhaust compatibility / change on Thu Dec 19, 2013 9:40 pm

Rabidchiwawa007

avatar
Platinum member
Platinum member
Interesting. What is in that big bulge then. Maybe when I get my new set up I'll cut it open and find outRazz.

So of all those aftermarket mufflers and the older stock square muffler, which is the quietest?


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

5Back to top Go down    Crack on Thu Dec 19, 2013 10:55 pm

Das Bitchz

avatar
active member
active member
My muffler cracked just like yours where the welding meet the 2 parts, after reading about it I knew that welding this thing again would only last so long!...I rode all summer with this problems. The Bike was lacking in power, the sound was weird and different, and it backfired from time to time!
if you weld it back it will brake again...

I finally decide to purchase a complete system call the Black Whole muffler made by RB Racing...these guy knows what to do, the owner is pretty smart and knowledgeable about racing, he's one step above, go and see it, they make this thing in black or chrome and it takes about 120 days to ship. so plan in advance. cost is around $1100.00 usd but there is nothing better outhere, much nicer and better then the original heavy exhaust!

www.rbracing.com

    

6Back to top Go down    Re: Exhaust compatibility / change on Thu Dec 19, 2013 11:24 pm

duck

avatar
Life time member
Life time member
Rabidchiwawa007 wrote:Interesting. What is in that big bulge then. Maybe when I get my new set up I'll cut it open and find outRazz.

So of all those aftermarket mufflers and the older stock square muffler, which is the quietest?

The Staintune on my 93 K1100LT is roughly about the same as stock noisewise.

Same for the Remus on my 94 RS but supposedly there are two of them and one is louder than stock. I don't think we're talking HD loud though.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

7Back to top Go down    Re: Exhaust compatibility / change on Thu Dec 19, 2013 11:34 pm

RicK G

avatar
VIP
VIP
My staintune is loud far louder than I or the cops like. I think the PO used a crowbar down the middle the on it. I cant see anywhere it looks modded but I will have to do something or sooner than later I am sure to get a ticket to the policemans ball and they ge a bit expensive nowdays.


__________________________________________________
If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

8Back to top Go down    Re: Exhaust compatibility / change on Fri Dec 20, 2013 12:45 am

duck

avatar
Life time member
Life time member
RicK G wrote:My staintune is loud far louder than I or the cops like. I think the PO used a crowbar down the middle the on it. I cant see anywhere it looks modded but I will have to do something or sooner than later I am sure to get a ticket to the policemans ball and they ge a bit expensive nowdays.

I've had two or three of them on my Ks. Didn't seem louder than stock but sounded "better" (subjective) up above 4K RPM. JMHO.

The loudest one I had was on a K75. Not too loud but enough to make listening to music while riding not so great. Got rid of it and went back to a stocker K75 exhaust. YMMV.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

9Back to top Go down    Re: Exhaust compatibility / change on Fri Dec 20, 2013 2:59 am

Rabidchiwawa007

avatar
Platinum member
Platinum member
Hmm. I'm thinking I'll go with the earlier stock square muffler then. I remember that being a LOT quieter than this round one on the '92. Plus, I can get those on ebay, with the headers, for under $100. The aftermarket mufflers are like $350 minimum used. I'll just have to make some mounting bracket stuff if I remember right, and deal with the center stand aligning with the pipes / muffler.


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

10Back to top Go down    Re: Exhaust compatibility / change on Fri Dec 20, 2013 4:22 am

charlie99

avatar
VIP
VIP
or send one over to caferacer 62 for a little modification perhaps ?

awesome sound ...not quiet erm so far , but free flowing

our mates albyalbatross and saxon7 have a great admiration for the standard exhausts with just a tweek or two

giggles


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

11Back to top Go down    Re: Exhaust compatibility / change on Fri Dec 20, 2013 4:24 am

MikeP

avatar
Life time member
Life time member
Rabidchiwawa007 wrote:Interesting. What is in that big bulge then.

It's an expansion chamber. Think of it as part of the silencer. If it wasn't there, the silencer would have had to have been as long as the one fitted to 2-valve bikes.


__________________________________________________
1992 K1
1993 K1100R (used to be an LT)
    

12Back to top Go down    Re: Exhaust compatibility / change on Fri Dec 20, 2013 4:38 am

Rabidchiwawa007

avatar
Platinum member
Platinum member
@MikeP: ooooohhhhhhhhh, makes sense.

@charlie99: In relation to the older stock square muffler, right? What modifications are you referring to?


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

13Back to top Go down    Re: Exhaust compatibility / change on Fri Dec 20, 2013 5:03 am

charlie99

avatar
VIP
VIP


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

14Back to top Go down    Re: Exhaust compatibility / change on Fri Dec 20, 2013 10:52 pm

Rabidchiwawa007

avatar
Platinum member
Platinum member
Interesting. I'm not really sure what he did exactly though. I've never torn one apart myself so I don't know that much about how they work aside from how to put it on the bike and take it off! Weird that the same part is different dB ratings though. Either way, the difference between 89 and 92 dB doesn't seem like it'd be all that much.


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

15Back to top Go down    Re: Exhaust compatibility / change on Sat Dec 21, 2013 1:38 am

charlie99

avatar
VIP
VIP
3 db (is twice as loud by sound level equations) ...but little working difference really ......but 3 db also equates to less restrictions .
unfortunately after the mods the noise went up by at least 6 db...so might be a pain for some commuter types trying to get away quietly in the early morning ....but very reminiscent of the old Honda fours with 4 into 1 extractors and more open pipe

it does sound awesome under load and at speed ...4000 +

was just a heads up mate


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

16Back to top Go down    Re: Exhaust compatibility / change on Sat Dec 21, 2013 4:05 pm

Brad-Man

avatar
Life time member
Life time member
Das Bitchz wrote:My muffler cracked just like yours where the welding meet the 2 parts, after reading about it I knew that welding this thing again would only last so long!...I rode all summer with this problems. The Bike was lacking in power, the sound was weird and different, and it backfired from time to time!
if you weld it back it will brake again...

I finally decide to purchase a complete system call the Black Whole muffler made by RB Racing...these guy knows what to do, the owner is pretty smart and knowledgeable about racing, he's one step above, go and see it, they make this thing in black or chrome and it takes about 120 days to ship. so plan in advance. cost is around $1100.00 usd but there is nothing better outhere, much nicer and better then the original heavy exhaust!

www.rbracing.com

So what does it sound like compared to stock??????

    

17Back to top Go down    Re: Exhaust compatibility / change on Sat Dec 21, 2013 9:10 pm

Das Bitchz

avatar
active member
active member
Brad-Man wrote:
Das Bitchz wrote:My muffler cracked just like yours where the welding meet the 2 parts, after reading about it I knew that welding this thing again would only last so long!...I rode all summer with this problems. The Bike was lacking in power, the sound was weird and different, and it backfired from time to time!
if you weld it back it will brake again...

I finally decide to purchase a complete system call the Black Whole muffler made by RB Racing...these guy knows what to do, the owner is pretty smart and knowledgeable about racing, he's one step above, go and see it, they make this thing in black or chrome and it takes about 120 days to ship. so plan in advance. cost is around $1100.00 usd but there is nothing better outhere, much nicer and better then the original heavy exhaust!

www.rbracing.com

So what does it sound like compared to stock??????

Sound is about the same with higher tone I've find!...but I heard it from another K100....I'm still waiting after mine, I should get is soon..(ordered in August!!) and when I get it I'll do a quick video on you tube so you can listen to it!

    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum