The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: lamont on October 10, 2008, 11:05:45 PM

Title: drilled stock mufflers
Post by: lamont on October 10, 2008, 11:05:45 PM
Just scored a nice black 81 R65 with only 11K from a guy in Missouri, the exhaust was painted black and the ends of the stock muffs are drilled out , it sounds cool and I swear its more peppy than my other R65s,of course it could be a pigment of my menstruation,  has any one ever done this mod? Does it make a few more ponies???
Title: Re: drilled stock mufflers
Post by: beemer on October 12, 2008, 05:22:49 AM
Well the only thing you would get over here in the UK were policemen riding the ponies!!!!! ;D
Title: Re: drilled stock mufflers
Post by: montmil on October 12, 2008, 07:06:35 AM
Quote
Just scored a nice black 81 R65 with only 11K from a guy in Missouri, the exhaust was painted black and the ends of the stock muffs are drilled out , it sounds cool and I swear its more peppy than my other R65s,of course it could be a pigment of my menstruation,  has any one ever done this mod? Does it make a few more ponies???

Are you parting out the '81?
Title: Re: drilled stock mufflers
Post by: lamont on October 12, 2008, 09:35:26 AM
no, its a keeper
Title: Re: drilled stock mufflers
Post by: montmil on October 12, 2008, 03:33:33 PM
Quote
no, its a keeper

Rats!  ;)

Monte
Title: Re: drilled stock mufflers
Post by: Justin B. on October 12, 2008, 08:34:26 PM
I looked at an R100 that had this done, don't know if it really helps or not but louder pipes always make ME feel like I'm going faster!  ;)  If you don't like it you can weld the holes bnack in and touch up the paint.
Title: Re: drilled stock mufflers
Post by: R65Guy on October 14, 2008, 11:21:30 PM
For what it is worth....  Back in the 80's Joe Minton of Motorcyclist magazine wrote an article called Black Tie Boxer and he suggested drilling out the rear baffle inside the mufflers to gain a bit of power and give it a throatier exhaust note.   Seems like you needed a 5/8" or 3/4" hole saw and a long extension.  I always meant to try the mod but never have since I didn't have the tools.  Some folks said they just sharpened a long piece of rebar and punched a hole instead.

Neal
Title: Re: drilled stock mufflers
Post by: Billmc on April 04, 2018, 11:31:13 AM
Sooo a response almost 10 years in the making!

I have done this "mod' to every bike I've owned including a Honda S90, a Harley Springer and this Mono and all the others. I don't know if it really helps performance but it sounds like it does  ;)

A 3' piece of 3/4" galvanized pipe sharpened on one end and a 3lb. mall seem to do the trick. I attack it from both ends of the muffler in case its baffled on each end, as it is on the R65. Again I don't know if it helps but it sure sounds better to my way of thinking (good-by Singer sewing machine, hello motor with guts  ;D)
 I never changed anything else and none of them ran richer or leaner afterward, just sounded and the always subjective 'felt' better.
Title: Re: drilled stock mufflers
Post by: Bob_Roller on April 04, 2018, 05:12:15 PM
I did this to the original mufflers a year or two after getting my '81 R65, no change was detected in power or exhaust note .