Exhaust pipes vibrate (noise) when rpm's are high (78 xs400 2-e)

[abobber91]

They will vibrate almost every time the rpm's are higher than about 3 or 4k. During acceleration from a stop light, it feels like when it starts to vibrate, thats the time to shift up a gear.

The vibration then stops when my rpm's decrease because I shifted up, but will then start to vibrate again as I speed up before shifting up again.

It sounds like the vibration noise is coming directly from the right muffler (maybe the left one too). The mufflers do have rusted spots where the metal completely fell out forming holes close to the opening of the muffler.

I've tried to shift the muffler around with my hand to see if its loose but seems pretty secure.

I cannot tell if its the engine causing the muffler to vibrate or if its something in the muffler thats loose..

 

[Tombo]

Could be loose baffles. The pipes that came on my bike were blued, and the baffles were loose. I hear that running hot like that can make the baffles go loose from the more extreme heat. Sounds like the vibration was happening in the same area of the revs. Are your headers blued? Could also happen from rust. I have new pipes from fleabay, solved the problem.

 

[drewpy]

if original, there are 2 pipes in the down pipe, I bet one has come away and its frequency is where your at 4k revs

 

[xschris]

Looks like you need some new mufflers

 

[Lupe]

did you try knocking with your knuckles or a rubber hammer against your mufflers to see what might be loose?

 

[abobber91]

This is the right-side muffler. Left one is also pretty much the same but not as bad. CLearly the previous owner took aluminum tape and taped up the holes but looks like they got burnt off pretty good.

The right muffler did seem to make a little rattle noise when i hit it my hand..

PM me if anyones got another pair

I am also wondering how to choose for mufflers? I do not want to have to change up the jetting in the carbs or the stock air intake if i can't find the exact same pair.

Theres a huge motorcycle salvage yard close by with hundreds of clean looking mufflers for like $15 - $25 each but I never know which ones would work

 

[Scorpio1963]

My exaust had big gaping hole right where the Hpipe is.The previous owner tryed patching it with piece of sheet metal and did a lousy job.Then they tryed wrapping aluminum tape around.I did a beter job with tin can and hose clamp temporarlyNow I have a new Hpipe but no mufflers and looking for a set also.If I dont find anything cheaper Im going to pick out something from Mikesxs

 

[xschris]

I think you will need to replace those.