Mufflers & good vibrations

82 750 Twin.

A couple of months ago after the third car in a couple of days did its best to knock me off by changing into my lane on a multi lane road I decided it was time to get a bit ‘rowdier’. Not too loud just enough so they could hear me behind their glass as I was worried that it could upset their busy schedules if they had to stop and pick me up off the ground after hitting me.

I promptly purchased a set of Dunstall replica slip on mufflers with removable baffles (I was previously running Dunstall copies with fixed steel baffles which were just a bit louder than stock). The theory being I’d be able to muck around with the muffler baffles to get a sound level I was comfortable with, (I am not an advocate of extremely loud pipes). These pipes are available in the US from Dennis Kirk, JC Whitney etc – easily identifiable by the end cap; the ones with fixed baffles have a greater angle on the reverse cone.

If you decide to purchase a set also order some baffle packing as the packing that comes wrapped around the core is, I suspect from a Chinese workers collection of belly button fluff. This promptly blows out the rear of the muffler after a few hundred of miles – these mufflers are also very loud as they are delivered! Still being quite loud with decent packing I went to my local muffler shop and got a pair of 150mm off-cuts that fit inside the perforated baffle core and hack-sawed a set of cuts 25mm apart (alternating around the pipe) and ‘dented’ as shown in the attached picture. This was inserted in the baffle end screwed in and they knocked back the sound to acceptable levels – nice and deep, noticeable but not annoying at standard riding and a decent roar when giving it a bit of stick. A reasonable burble on the open road as well.

Side note - I needed to shim by needles to rich it up a fraction.

THE BONUS & THE POINT OF THIS POST
Other than the added volume (I’ve had no problems with cars since) a bonus is the bike rides a heck of a lot smoother. Not just a bit – a lot. I presume its all to do with back-pressure and exhaust pulses. I’d be interested to see if any one else has had a similar experience with vibration – good or bad – with a just muffler change.

PS – its been snowing in my city this week in New Zealand.

Cheers

Allan B

Post edited by: AllanB, at: 2006/06/23 04:05

The baffle insert I made is below

I also have had that experience in the last few days, almost being run off the road. I feel like my little horn needs to be a large air horn like on my fire truck. HONK!!!!! Luckily I was able to stay out of there way. It looks like you do some very fine cutting.

good luck keeping the cages away!!
I run my GPZ 1100 with a competition kerker 4-1 with no baffle and no end cap (I bought it that way and think that it is obnoxious.. just have not gotten around to putting the new pipes on yet) (shakes the windows of the house if I rev in the driveway)
anyway.... I am dodging cages as much as ever.... maybe I need a swirly blue light on my bike....

Loud pipes don't "save lives", the whole premise is a bunch of baloney.
Loud pipes DO piss people off and lead to all sorts of no motorcycle ordinances and restrictions.
If you want to keep the rest of the population who doesn't ride off your back you will keep it quiet.

Post edited by: alteran, at: 2006/06/25 21:03

alteran wrote:

Loud pipes don't "save lives", the whole premise is a bunch of baloney.
Loud pipes DO piss people off and lead to all sorts of no motorcycle ordinances and restrictions.
If you want to keep the rest of the population who doesn't ride off your back you will keep it quiet.<br><br>Post edited by: alteran, at: 2006/06/25 21:03

:S relax,i hear more loud honda civics with loud exhuast than bikes they seem to be the ones acting stupid most of the time.

Amen to that Wireman!