Hey guys, I just wondered if any of you had ever tried drilling a few 10mm holes in the exhaust end cap of your K100, if so did it effect the performance and what did it sound like?  As my K100 trike purrs like a kitten, but I want it to roar like a lion on acid

there are other ways of doing it

look for a thread zorst

mighty loud and quality at the same time ....at least 2 members have one using the same standard muffler ...modified

charlie99 wrote:there are other ways of doing it

look for a thread zorst

mighty loud and quality at the same time ....at least 2 members have one using the same standard muffler ...modified

Yes I've checked out the zorst threads, but just wondered what a simple and free mod would achieve, as the sound of the standard K100 is lacking in personality, in fact it almost sounds like an electric wheel chair!

Bert 2.0 ( Caferacer64) modified my muffler and converted it into a Zorst for me and it's great. Sounds like a bike now. There's probably little point in drilling holes in it...you'll need to cut the end off and do some mods as it's fairly elaborately constructed and also each one seems different depending on what year model it is. This is what it sounds like now.

https://www.youtube.com/watch?v=b0KAJtFfmLw&list=UUc7NNjWO7nHEhMpErSDJ5Hw


Schoorn.

Saxon7 wrote:Bert 2.0 ( Caferacer64) modified my muffler and converted it into a Zorst for me and it's great. Sounds like a bike now. There's probably little point in drilling holes in it...you'll need to cut the end off and do some mods as it's fairly elaborately constructed and also each one seems different depending on what year model it is. This is what it sounds like now.

https://www.youtube.com/watch?v=b0KAJtFfmLw&list=UUc7NNjWO7nHEhMpErSDJ5Hw


Schoorn.

Thanks for the link,

Yes your muffler certainly sounds better, but still a bit quite.  Looking on the web many people have modified their exhausts by drilling out 4-8 holes on the end cap and there seems to be a real improvement.  My only worry is that the K is not your typical bike engine to begin with, which makes things less predictable, that's why it would be good to hear from someone that has already tried, plus also back pressure has to be taken in to consideration.

Don't like to spoil a story but a K is a very typical twin overhead cam 1 litre engine. The top end gear is very close to identical to a Kawasaki Z900.
Many have tried over the years to improve on the stock K100 muffler but none have succeeded to any real degree.
If it's noise you want then get someone to make a collector and put a laser can on it, that'll make it bellow.
Never know it just could save some lives in the traffic behind you. 

Symbolizm wrote: . . . my K100 trike purrs like a kitten, but I want it to roar like a lion on acid

This year I switched to a tuned exhaust and stubby muffler with baffle plates. I was expecting a much louder noise (Harley loud!), but that is not the case. The engine emits a throaty sound that resonates nicely during rapid acceleration, but it's not really that loud.   

This gets me to thinking, what was BMW trying to achieve with this overly long silencer? A bit of over-kill IMO.

Me thinks I have nothing to loose by drilling some holes the correct size that can be replaced with self tapping screws if necessary.  As I could go to all the expense of a custom exhaust to see no real gains to justify the price.

I think that you are wasting your time. If a few holes in the rear of the silencer would give more noise then there will probably be a drop in power and an increase in consumption. I would expect that BMW, who probably spent millions on exhaust design, would have come up with the best all round system.
But try it and let us know what you find, there is a 0.01% chance of improvement and a 99.99% chance of messing up a good exhaust system. You could buy a Harley and have more noise but only 65 bhp from a bigger engine.

On my K100 project bike a previous owner has had problems with the silencer heat shield fixings and simply drilled right thro into the silencer and fixed the heat shield with self tapping screws. With all of this removed the sound emitted  is that of a badly blowing exhaust and really isn't very nice to the ear. John