Exhaust can/header separation issue.

[Biker Dash]

I run the Cobra exhaust, and as much as I love it, I am having an issue where the right lower can is separating from the header. This has been an ongoing issue I have been having with this bike, and I am wondering if I may have tweeked the header when I was removing the stock exhaust somehow. If so, I would guess that I am in need of a new header.

That exhaust clamp is always clamped down tight, so it is not a case of it loosening up.

Here is a pic of what is happening. (last week, during a longer ride, it actually separated fully. Was VERY loud for the remainder of the ride home.)

 

[Traumahawk]

The headers to the back cylinders are able to move around a surprising amount. I found this out when I put slip on mufflers on. Could that clamp be a little bit loose, allow the header to move around, and loosen up further?

 

[Mr. Max]

Kerker cans had a small screw at the end of the midpipe, that locked can in place. Screw was under clamp at the bottom of the pipe, same thing might work there.

 

[Biker Dash]

The headers to the back cylinders are able to move around a surprising amount. I found this out when I put slip on mufflers on. Could that clamp be a little bit loose, allow the header to move around, and loosen up further?

I just tightened the clamp as tight as it will go, and I was able to pull it apart by hand. I do not think it is the header pipe, unless the exit on the header was compressed to a size that is just a hair too small.
I think I shall go to the parts store, and see what I can find, even if it is just a temp fix. (It could be that my can and header pipe are both on opposite extreme ends of manufacturer's tolerances, I guess)

Kerker cans had a small screw at the end of the midpipe, that locked can in place. Screw was under clamp at the bottom of the pipe, same thing might work there.

If you could show me a pic of exactly how it is set up, I would be grateful, thank you.

 

[Rusty McNeil]

You could cut a slit in the cobra can making it about an much
Long. This would let the clamp actually decrease the diameter of the pipe as it tightens down.

Set screw idea is good too

 

[[email protected]]

I'd rent a tail pipe expander and put it in the end of the header to increase the OD of the pipe slightly.

Then, I'd loosen the bolts on the head a bit, re-attach everything and tighten it back up.

 

[Rusty McNeil]

I'd rent a tail pipe expander and put it in the end of the header to increase the OD of the pipe slightly.

Then, I'd loosen the bolts on the head a bit, re-attach everything and tighten it back up.

I like that idea, forgot about those handy tools..

 

[Fire-medic]

The advantage to that is you can do it on the bike, possibly. One of those Sears muffler tools, w/the segmented, pie-shaped pieces, which are banded-together w/O-rings is what I am thinking-of. Tighten the central nut/bolt, the segments move-out, and stretch the metal.

When I was making my Frankencanister for my UFO 4/1, I went to the local muffler shop w/my exact dimensions, and $10 and about 2 minutes of time w/their hydraulic expansion tool got me great-fitting sleeve pieces to adapt my literbike canister to my flanges I made. I did slot the flange-welded tube about 1-1/4"in a couple places to allow it to close-up slightly for a better grip w/the barrel-bolt clamp. You might also check you aren't using up all of the machine screw threads on your barrel-bolt clamp, that would make your fittings loosen.

I think you would have to possess the grip of Thor clutching his Hammer to expand a steel tube w/a hand-held 'expander.' Those look like something a gynecologist would use, after telling her to "put your feet into the stirrups!"
Can you say, 'speculum? I knew you could!'

This:

Not these:

I expect Harbor Freight Tools has a cheap one. No, not the speculums!:rofl_200:

I'd rent a tail pipe expander and put it in the end of the header to increase the OD of the pipe slightly.

Then, I'd loosen the bolts on the head a bit, re-attach everything and tighten it back up.

 

[ImCannibal]

I had the same issue with my supertrapps on the left side, I just cut small slots about 3/4" in the pipe on the can and used a clamp, fixed everything

 

[Biker Dash]

You could cut a slit in the cobra can making it about an much
Long. This would let the clamp actually decrease the diameter of the pipe as it tightens down.

Set screw idea is good too

I had the same issue with my supertrapps on the left side, I just cut small slots about 3/4" in the pipe on the can and used a clamp, fixed everything

The cans already have the slits on the header end.

I went and bought some of that exhaust repair tape today. Thought maybe that might work.

Would not fit inside the cans... shit.
And I say shit for a reason. That shit sticks worse than baby shit to a blanket! You could Catch Mothra with this stuff!!!

It seemed to add enough stickiness that the header and can can't be pulled apart now. Let's see how well it will hold up.

 

[Rusty McNeil]

This:

Oh, that's what we were talking about?

Damnit!

 

[ImCannibal]

Yeah, once that exhaust tape gets hot it's pretty much not coming off in any orderly fashion that doesn't involve a grinder with a wire wheel. But, its thin enough to use to fill small gaps between pieces of pipe that you don't want to weld. It isn't actually very good at fixing cracked exhaust on cars like it's supposed to, but if you're buying it at wally world or vato-zone then you're probably using it for scientific unintended purposes anyways haha

 

[Biker Dash]

Yeah, once that exhaust tape gets hot it's pretty much not coming off in any orderly fashion that doesn't involve a grinder with a wire wheel. But, its thin enough to use to fill small gaps between pieces of pipe that you don't want to weld. It isn't actually very good at fixing cracked exhaust on cars like it's supposed to, but if you're buying it at wally world or vato-zone then you're probably using it for scientific unintended purposes anyways haha

Hey! My sidewalk science works! (some of the time

)

 

[Mr. Max]

I drawed a pic of how it was on kerkers, that problem has many solutions but this is what I would do, I think it is really a failsafe solution. Can stays in place even without clamp.

I cant draw, but hope you get the idea.

Basically you fasten screw to inner pipe, and the tip holds outer pipe in place. Hard to explain with my english (and drawings lol)

 

[Biker Dash]

I like this idea. I don't think the exact way you have done this would work with the Cobra setup, but I could easily make a setup similar that would work. Just need some self tapping screws. And something similar to Locktite that will prevent the screw from coming out... or maybe a simple metal hose clamp over the set screw...

 

[Mr. Max]

Well what I see in your pic I believe its totally doable, just get them apart, remove clamp, put them together, drill hole that is suitable for your tin screw through both pipes, pull pipes apart again and then drill bigger hole to outer pipe so screws tip fits in, slide all together, add screw and tighten clamp in its normal place, screw underneath it, thats it. And thats good enough for Supertrapp..

 

[Biker Dash]

Well what I see in your pic I believe its totally doable, just get them apart, remove clamp, put them together, drill hole that is suitable for your tin screw through both pipes, pull pipes apart again and then drill bigger hole to outer pipe so screws tip fits in, slide all together, add screw and tighten clamp in its normal place, screw underneath it, thats it. And thats good enough for Supertrapp..

Yeah... that is what I figured when I thought about it while out on my ride. And that pretty much sums up what I shall be doin. I just might do all four that way, just to make certain the others do not get the chance to do the same separation games on me.

 

[Biker Dash]

Ended up doing it pretty much like this. Because of a low charge drill, and dull drill bits, (and my one sharp one breaking) it took me all afternoon to do. SHOULD have only taken me 10 minutes, if that, to do, had I had good drill bits already on hand.

I should consider doing this with the other three pipes, just as a bit of preventive medicine.

 

[ImCannibal]

Hey! My sidewalk science works! (some of the time

)

I'm pretty sure most of us use black magic and driveway science to keep our bikes on the road, with the occasional dose of pure wizardry from the more knowledgeable guys like Sean.

 

[timpilot]

The advantage to that is you can do it on the bike, possibly. One of those Sears muffler tools, w/the segmented, pie-shaped pieces, which are banded-together w/O-rings is what I am thinking-of. Tighten the central nut/bolt, the segments move-out, and stretch the metal.

When I was making my Frankencanister for my UFO 4/1, I went to the local muffler shop w/my exact dimensions, and $10 and about 2 minutes of time w/their hydraulic expansion tool got me great-fitting sleeve pieces to adapt my literbike canister to my flanges I made. I did slot the flange-welded tube about 1-1/4"in a couple places to allow it to close-up slightly for a better grip w/the barrel-bolt clamp. You might also check you aren't using up all of the machine screw threads on your barrel-bolt clamp, that would make your fittings loosen.

I think you would have to possess the grip of Thor clutching his Hammer to expand a steel tube w/a hand-held 'expander.' Those look like something a gynecologist would use, after telling her to "put your feet into the stirrups!"
Can you say, 'speculum? I knew you could!'

This:

Not these:

I expect Harbor Freight Tools has a cheap one. No, not the speculums!:rofl_200:

AutoZone (and probably the other auto parts stores) have free loaner exhaust pipe expanders. I used one to expand used exhaust tips I put on my '88 Fiero Formula.