Loose exhaust at flange

[cdn-bigfoot]

I've had increasingly bad popping on deceleration.
At first I thought it was a lean mixture.
A plug chop proved that likely not the cause.
During a recent 300 mile road trip the popping became much worse. And the engine lurched slightly when cruising. At hard acceleration the exhaust sounded different than normal. When I got home I immediately checked the exhaust flange bolts for tightness. All tight. But the front pipe moved 3/8 inch inside the tight flange. After removing the pipes completely I found that the chrome end of the pipe was not affixed to the pipe. This means the flange has nothing to grab. Thus the loose pipe, and the popping.

My question, and I think I know the answer is.....
Is this chrome ring supposed to be tacked to the pipe with a welder?
The other one is on good and tight.
http://www.cyclespot.com/forums/photopost/data/988/medium/exhaustflange.jpg
http://www.cyclespot.com/forums/photopost/data/988/medium/ehaustdraw.jpg
19. retaining ring (2)
20. exhaust gasket (2)
26. Exhaust manifold flange (2)

[Shockwave]

The "tip" should be affixed to the pipe. Was it pressed on or does it look like a weld broke? What kind of exhaust is it?

[cdn-bigfoot]

The "tip" should be affixed to the pipe. Was it pressed on or does it look like a weld broke? What kind of exhaust is it?

It's a Cobra exhaust system.
I don't see where a tack weld may have broken. But its possible?

[Shockwave]

I'm not familiar with the Cobra exhaust. I would think there would be either a weld or something there. Maybe it didn't get welded at the factory? Is the other pipe welded? Maybe they both should be.

[cdn-bigfoot]

It's pressed on at the factory.
My welder friend tacked it on with 3 tacks with his MIG. I cleaned up the welds with a Dremmel.
I had him do the pipe that was still good to.

I heard back from Cobra Exhaust. They said they would repair or replace them if I shipped the pipes to them. OK I would be without my bike for a month or more in a climate that has a 6 month riding season. Not worth it. I'm not sure if they would honour the waranty once they found out I'm not the original purchaser and don't have a receipt. Sometimes a "lifetime warranty" is worth spit.

Anyway. Fixed my pipes. Put 'em back on. They look, work and sound great. And welded they are better than they were new. Just a little pop on hard decel. Like before.
PERFECT!

[JayDee5150]

Strong work CDN...with a riding season as short as yours, i'd have done the same.

Thanks for posting up those photos of the problem...belive me next time my exhaust comes off my bike i'll be checking to see if my rings or on tight and sealed to the header pipe....!

[cdn-bigfoot]

Strong work CDN...with a riding season as short as yours, i'd have done the same.

Thanks for posting up those photos of the problem...belive me next time my exhaust comes off my bike i'll be checking to see if my rings or on tight and sealed to the header pipe....!

Thanks JD.
2 days without riding.
Not bad for a hack like me.
I think I had as much fun figuring out the problem and wrenching on the bike myself as I would have had riding anyway. Wel .... glad I got it done in 2 days.

No riding for the next 5 days anyway.
I'm off to cover the Iowa Corn Indy 250 race this weekend.
Look for me in the pits on race day.
Not wrenching, but shooting video for CTV News.
YeeHaw!

[cdn-bigfoot]

4 mos since the previous post on this topic.

My bike started popping again and has gotten much worse on the last 2 rides.

I pulled on my pipes and whoa and behold.... wait for it!

The front pipe is loose in the exhaust flange again!
I had my Cobra pipe fixed by a welder friend after the pressed on sleeve came off and the pipe was no longer being held tight to the gasket by the flange. Well the welds must have broken. Pipe is loose again.

Back to the welder or buy new pipes????
I love these pipes. Maybe I'll get him to weld all the way around the sleeve instead of just a few tacks?

[Graywolf]

Might want to look at some better support for the pipes. How are they supported toward the rear?

[cdn-bigfoot]

Might want to look at some better support for the pipes. How are they supported toward the rear?

I know where you're going with this. Good thought. They can't handle the vibrations right?
Everything is well supported.
A large bolt on plate mounts the rear of the pipes to the frame.
I have also added an exhaust mount near the timing cover made of steel and shock rubber. It's a proper exhaust hanger. Everything there is tight. I think it was a defective pipe from the go.
I'll fix it with more solid welding and post a follow up photo. Riding is done here for the year soon. Not sure I'll get a chance to realy give em a good extended test before the snow flies.

[old skool]

glad ya got them fixed, should work as good as new. ride that suckaa

[cdn-bigfoot]

glad ya got them fixed, should work as good as new. ride that suckaa

I'm fast... but not that fast.
Just posted the new found old problem 21 minutes ago.
I'll wrench on them tomorrow.

Maybe still get a ride in this year.

[Graywolf]

Not sure I'll get a chance to realy give em a good extended test before the snow flies.


Leave it with the Florida crew for the winter. We will test it out!

[ryno18000]

Are the materials the same type? Are you welding mild steel to stainless? This may be why, the tack wasn't so effective. I am in no way, a welding expert, but I do know, that some stainless steels need to be preheated and post heated to make a good weld.

[OnegoodHorse]

I hate to point this out, but pipes that mount to the frame on a rubbermount engine is a recipe for...breakage. Remember, a rubbermount engine when it's rock-n-rollin can move a significant amount. Also, email customer support and tell them the flange welds broke, Chance they'll send you some new pipes.

[cdn-bigfoot]

I hate to point this out, but pipes that mount to the frame on a rubbermount engine is a recipe for...breakage. Remember, a rubbermount engine when it's rock-n-rollin can move a significant amount. Also, email customer support and tell them the flange welds broke, Chance they'll send you some new pipes.

I know what you're saying. That's why I made the front mount a rubber "shock mount". Did my best and what I thought was right.

I just e-mailed Cobra.
See what they can do.
I will post with their response.
They are seriously great pipes and I would love to keep 'em.