My bike does not like the end cap...

[MitchP]

Comrade HuffyDavidson was kind enough to figure out how to get my bike running for the first run. The solution was to take off the end of the exhaust pipe (grubee GT5/66c). And it worked. really well.

But it's really loud. Like shooting .22 pistols loud. So I put the cap back on and it lost a lot of power? I don't know what to do.

Tomorrow I am going to buy a large washer and fit it over the end. Drill some holes so it has more flow than the original but more back pressure than no cap.

What happens if it has no back pressure like right now? Should I get a new pipe? or is it the cap like the one i removed slows it down but keeps it quiet?

 

[JonnyR]

pull the guts out and put the cap back on you have a EPA approved(screwed up) muffler it has a very restrictive set of baffles in it they say is a cat converter but its a oil catcher and clogs and is useless

running it without the muffler is a bad idea it will hurt the engine and it is robbing you of full power as well a expansion chamber exhaust will make it flow most efficiently

 

[MitchP]

Yeah the baffles are junk. It made der EPA happy though.

One problem- the threaded rod/pin that holds the bolt is connected to those baffles. And it is welded in there pretty good.

 

[JonnyR]

some people have drilled a hole in the muffler to fix this when i was using that junk muffer i had to crush mine to make it work so the exhaust went around ether side of the cat and i made a flat end cap out of steel with 5 holes 4 1/4 inch ones and a 1/8 one in the center for the stud and bolted it on like that

 

[MitchP]

I drilled holes in the end cap. it's an increase of about 240%. We'll see.

What about these? one webiste claims they're for a 4 stroker?
http://www.kingsmotorbikes.com/bike-motor-engine-fancy-poo-poo-pipe.htm

 

[maniac57]

I found this pipe at a local scooter shop in the junkpile. I cut and rewelded the headpipe to fit my Pig and am thrilled with the sound and power. It no longer sounds like a weedeater but much more like an actual motorcycle does. Idles better and has a real sweetspot in the powerband right where I cruise. You can do this cheaply if your scrounging skills are up to snuff.

You might also try this for better sound control on a gutted stock pipe. It's simply electrical conduit bent to fit and welded to the stock pipe with a hanger on the chain tensioner.