Topic: Making an effective baffle for drag pipes, etc.

[MCRider]

Prompted by diiscussions on loud pipes. I have this racing 4-1 for CB750, made one off to match the Honda Bol dor pipe. Down pipes real close together, collector dead center under engine, exit under right side of swingarm tucked in. I suppose it was to allow a close fitting fairing, but it doesn't allow filter change or drop the oil without removing. Hard core, absolutley no ground clearance problem. Exit is 2.5in tube with no baffle, way too loud. (Hanging on wall)

So, I had an old CB750 long baffle laying around, about 12" long.  Welded a round plate with a large hole in it to one end, the other end which goes into the pipe, was smaller diameter stem. So cut another round plate, OD the ID of the exhaist, drilles hole large enough to sliip over the stinger end of the baffle, and welded it. Whole thing slips into end of exhaust pipe, held in place with a bolt. Beautiful sound, bolt never came loose.

Other options if you don't have baffle laying around as that's the expense: these from JCWhitney fit drag pipes: http://www.jcwhitney.com/internal-baffles/p2006266.jcwx

Or these:    http://www.jpcycles.com/product/4410015?N=274774&Nao=20&results=10

Or this:


Same thing, cut some round plates the diameter of the pipe you're filling, weld them on with a tab for the bolt, slide them in and secure with a bolt.

Knocks the worst part of the sound off especially at idle.

[Terry in Australia]

Thanks for posting this thread Ron, I can't look at the pics due to the over-protective defence department firewall, but I'll check it when I get home. Have you ever seen the "Snuff or Not" kits that were around "back in the day"? They were a perforated disc that would fit inside your headers, on a spring loaded pivot?

The deal was you could turn them to the "quiet" position when tooling around in traffic, then turning them thru 90 degrees, you'd have a "straight out" system for racing. (or maybe just making lots of noise........) I bought a kit on EBay a few years ago and was gonna "reverse engineer" 3 more for a set of pipes I've got here, they've got some great "turn out" mufflers with no baffles which look really cool, but because of the "turn out" on the ends, are pretty much impossible to fit with any sort of baffle.

I Haven't done it yet, but I might give it a shot soon for a CB750 rat/cruiser I'm going to build. Cheers, Terry.

[MCRider]

Thanks for posting this thread Ron, I can't look at the pics due to the over-protective defence department firewall, but I'll check it when I get home. Have you ever seen the "Snuff or Not" kits that were around "back in the day"? They were a perforated disc that would fit inside your headers, on a spring loaded pivot?

The deal was you could turn them to the "quiet" position when tooling around in traffic, then turning them thru 90 degrees, you'd have a "straight out" system for racing. (or maybe just making lots of noise........) I bought a kit on EBay a few years ago and was gonna "reverse engineer" 3 more for a set of pipes I've got here, they've got some great "turn out" mufflers with no baffles which look really cool, but because of the "turn out" on the ends, are pretty much impossible to fit with any sort of baffle.

I Haven't done it yet, but I might give it a shot soon for a CB750 rat/cruiser I'm going to build. Cheers, Terry.

My post isn't too exciting, but i felt the need to say something.

Back in my Parts Dept day we sold the heck out of SnufferNots. Mostly for the CL77,CL350 crowd and similar bikes. Biggest problem was they couldn't stand up to the vibration hanging out at the end of along exhaust pipe. They would come apart and blow out. With your attention to design you can probably get them to work and hold together. I do think they were effective.

[Terry in Australia]

Thanks mate, and I just saw your pics for the first time, that Bol D'or pipe looks bloody magnificent mate! If it ever gets too heavy for your wall, I want first dibs!

[Mat]

Thanks MCRider. I didn't want to dissect my stock pipes until it became absolutely necessary. Wasn't sure how baffling worked in motorcycles, so this helps a lot. Going to save me a lot of money, too, which is great when you're in a master's program working as a sub.

[Coyote13]

A lot of Harley (mostly Sportster) guys fab up what they call a "lollipop" in order to generate backpressure. No idea if it affects the sound (I'd imagine anything blocking the pipe would help to muffle at least a little), but apparently they are pretty useful for tuning. The basic idea is this: weld a washer to the end of a bolt, drill a hole in your pipe to fit the bolt through, screw that bad boy in and you've got tuneable pipes. Rotate the lollipop parallel to the flow of exhaust for WOT performance, or close it up for more back pressure in a cruising situation. Super cheap, super easy, and it works surprisingly well (so they say)

[MCRider]

A lot of Harley (mostly Sportster) guys fab up what they call a "lollipop" in order to generate backpressure. No idea if it affects the sound (I'd imagine anything blocking the pipe would help to muffle at least a little), but apparently they are pretty useful for tuning. The basic idea is this: weld a washer to the end of a bolt, drill a hole in your pipe to fit the bolt through, screw that bad boy in and you've got tuneable pipes. Rotate the lollipop parallel to the flow of exhaust for WOT performance, or close it up for more back pressure in a cruising situation. Super cheap, super easy, and it works surprisingly well (so they say)

Thats pretty much what the "Snuff or Nots" do. Turned one way they Snuff, the other they don't.

http://www.honda305.com/cb77_800/cb77-818.htm