Please help me quiet my Kerker!!

[Heretic]

I am looking to quiet down my 4-1 Kerker with 2.5 inch baffle and cap. I actually bought a 2 inch cap online (just the cap) thinking that I could put it on for street and wife-on-back duty, and switch back to the 2.5 cap for track and dyno use, but the place came back and said it was discontinued (D'oh!). The damn thing is too loud. I tried to repack the baffle and it didn't help.

Loud is cool, but not all the time...

Anyone here willing to part with a 2 or 2.25 inch cap, know where to buy one, or offer any suggestions on how to mute the beast for under $50.? At this point I would even be willing to swap the Kerker can and a few bucks for a Supertrapp or something similar. It doesn't have to be in perfect shape, but decent. I am willing to take the HP hit for a few less decibals.

Any help would be greatly appreciated. Thanks!

 

[one2dmax]

you will need more then the cap to really be effective. You would actually also need the core baffle. I have other mufflers but they would be a lot more then $50 (though I may have a supertrapp but they fit totally differently).

Sean morley

 

[Heretic]

Why could I not just replace the cap? The diameter of the smaller cap would create much more back presssure than the 2.5 incher, and in theory would shut it up a tad. Maybe not as much as a 2.0 baffle and cap would, but probably enough for my purpose. I can replace just the cap in a minute flat. Replacing the whole baffle takes time and patience, and it is not something I want to do every weekend.

I know I will lose HP, but I will not be looking for races with the wife on the back (I have and I pulled the front wheel up...a lot, and I can't do that again.)

I am looking for just the cap (If it is possible, and if not I would like to know why, cause it seems like to would/should/could) so I can go from drag strip to quiet(er) ride in country with only a minute of tinkering.

Please help if possible. I'm a poor man with a loud bike.

 

[diggerzmound]

I am not sure how your new cap is held on, but if it has rivets on the end of the can and not the sides, I can help.

I am an atv nut and can't stop modifying them. One of them has an HMF pipe on it and was terribly loud, so I ordered the quiet core for it. It made a noticable difference, it took the raspy crack out the tone, still a nice deep mellow sound, but without the ear numbing crack.

If your end cap bolts or rivets on the end and not the sides, you can build or have built your own. Make a large washer that will fit under your end cap, with a piece of screen tubing that extends inside the can. Mine is made out of stainless, and is something that could be made locally by any machinist. HMF gets $35 out of these, I bet you can get someone to whip one up cheaper.

Here is the best picture I can find..

 

[Heretic]

Well the good and bad.

The good
On a whime I stopped by an old greasy motorcycle parts place that has been around since Willie G was suckin on momma's tittie and walked up to the parts counter and asked if they had Kerker k-series end caps in stock. This was a shot in a million. The parts guy shrugged and said 'I dunno, gimme a minute'. After around 7 minutes of looking he comes out and drops a dusty box FULL of kerker k-series end caps on the counter. Holy Crap! The answer to my prayers! He had five each of the 1.5 and 2 inch ones in there. When I asked about price, he stated "Ehh, 10 bucks for whatever one you want". I just paid $33. for one online and they came back and said that they were discontinued, so I was elated. I bought one with the 1.5 inch outlet. The end cap appears to be designed to fit whatever size baffle you have, there are three sets of notches built into it to line up with the baffle(s). The cap went on perfectly, no problem.

The Bad;

If it is quieter, its not by a whole lot, and now has an odd off idle cackle. Damn! It is kind of funny though, seeing such a small outlet produce such a loud noise, like a lion's roar from a kitten.

Sean, maybe at Topeka this year you can show me some other cans that you have. Right now I need to save enough to pay the taxes on our house and money is tight. Thanks everyone for the help!

 

[Rusty McNeil]

I rode with a guy last weekend that had an older 4-1 kerker that was the loudest, most annoying thing I have ever heard out of a max. Loud is OK by me but this one was raspy and high pitched also...don't think there was any end cap on it and don't know about baffles or packing either....

 

[one2dmax]

I do have a couple of small baffles for the kerkers but no packing (though you can get the stuff I am told from various sources besides motorcycle shops). They are a bit quiter but have a very loud and high pitched shriek at upper rpms.

Sean