Combat Wombat Pipe Mods

[DesertRat54]

Captain Eddy had a very interesting article in the January 2010 Resonator re: modification of the tail end of the stock Combat pipe. I'm wondering if anyone out there has tried this (or Ed, if you're out there, could you provide a summary of your impressions a year and a half later?). I remember that Ed said Harry had a very favorable opinion of this particular pipe. How noticeable is the change in performance? Does it add more in the way of "snap," or is there a noticeable gain across other areas of the power band? In short, was the time and effort worth it? As I recall, the article implied that this was a project for someone with not much else to do. I really have quite enough to do, thank you very much, but I've got this Combat Wombat project on the bench, and...well, you know.
Thanks,
Bill in Virginia

[racerclam]

I do know that Harry told me that the later pipes had some wire mesh screen stuff welded on the inside for noise reduction , you can iidentify this pipe by looking oround the outside of it for rose bud weld spots. Then all you have to do is split the pipe at the seems and remove the mesh and weld it back together . This makes it work like the earlier pipe , dont sound like fun though. That is a good pipe for bottom and mid range performance .

Rich

[DesertRat54]

Thanks, Rich. Yes, I recall that bit about the screen. And it does sound like a lot of grinding and welding. The pipe I have in mind is the earlier "flamethrower" type. I'd have to take a closer look, but I don't think it has the tell-tale weld marks that would indicate a internal screen.
Bill in Virginia

[Bullfrog]

Doing the final cone modification to the CW pipe is one of those detail things. It most certainly does help the performance of the pipe and engine . . . but you'd have to have a more sensitive butt than mine to really feel and describe how/where in the rpm band the improvements come. But that is how performance gets improved . . . adding up little bits and pieces.

Now the wire screening lining the walls of some of the Combat Wombat pipes . . . that is likely to be a different matter. I don't have a pipe with the screening (look for the spot welds) -- so I can't directly report on how removing the screening helps . . . but it surely must help. The screening changes the interior volume, increases flow friction, etc.

Ed
PS: I HAVE taken the time to remove the interior screening lining the walls of a Model 03 pipe. The result of that long, dirty, laborious process was . . . don't bother doing it. The street legal pipe is better off left in its quietest possible state . . . and I couldn't identify any performance change even with a stop watch.

[DesertRat54]

Thanks for your thoughts, Ed. I looked over the pipe again, and I see no "rosebuds" indicating an internal screen. Could it be that only the later model pipes had the screen? I think I'm going to start down this road, and see where it leads. I'll have some help from a friend who can/has welded anything/everything. With your specs and his expertise, I think this thing can happen. Your point is well taken about performance happening incrementally.
Bill in Virginia