Metallic Vibration Sound at High RPMs

*** Update: problem solved ***

*** Update: just kidding; problem not solved ***

After installing my Holeshot headers, I now have a metallic vibration sound (like a metal part rattling against another metal part) at higher RPMs when the engine gets more buzzy. I've done my best to use my ears to locate the source, but I can only determine that it is in front of me while sitting on the bike. I think that rules out the possibility of the connection between the header and mufflers rattling, and also the possibility of a foreign object in my pipes rattling around.

The most obvious possibility is that one of the brackets used to mount the headers to the engine is vibrating against the header pipe, but it seems that would require the bolts to be loose to allow the rattling. Before i go loosen everything, jiggle things aimlessly to ensure they are resting in the correct position, then re-tighten, are there any experienced mechanics out there that know of any common "gotchas" with header installation?

For example:

• One of the header pipes does not seem quite centered in the opening to the engine; do I need to make sure the pipe is inserted into the opening such that it does not contact the wall of the opening?
• I had a qualified mechanic verify that there are no leaks at the mounting point (based on looking/listening while idling and revving); Is it possible to have a small leak that only occurs at high RPMs? Would it cause a sound that could resemble metallic rattling?
• Is it possible that the mounting nuts are tight enough to avoid leaks, yet loose enought to allow the brackets/pipes to vibrate?

It's kinda frustrating to have the willingness and desire to perform work on my bike myself; I know just enough to be dangerous and get myself into situations like this where I become completely helpless :angry:

I get that noise from time to time, turns out it's my metal key fob rattling against the tripple tree.

Silent said:

I get that noise from time to time, turns out it's my metal key fob rattling against the tripple tree.

Click to expand...

I checked for loose items like this also. I pulled everything out of my glove compartment, and the only thing on my key is a wrist strap from some electronic gadget (it says "Samsung" on it... maybe it's from one of my old cell phones?).

It is a very tight fit at that old center mount-I had to do a little tweaking there on mine, though I didn't have a noise, I suspected I might when I put them in. I now have a set of centerstand mounts there that have the pipe mounts removed completely, as in cut out, ground, and painted all pretty like. Should also add that if a pipe is off center at the head interface, it will tighten up securely and give one the impression all is good, but it's cocked. Dales work is very good-the fit on mine were perfect there, but it bears checking out.

Found the problem...

The right header was resting against the head of one of the center stand mounting bolts. I swear I checked everywhere for contact like this when I installed the headers, but it was only visible from a certain angle (requiring my head to be completely under the bike to see the problem). I used a dremel to grind the edge of the bolt down to gain some clearance, then stuck a piece of an adhesive velco strip (the soft curly portion of the velcro) on both center stand mounting bolts on the right-hand side of the bike to dampen any possible contact with the pipe if the pipe vibrates enough to touch the bolts. The noise is gone and I hope the velcro stays in place.

Glad you found the problem, now all you have to worry about is velcro melting on the pipe when it touches.

UselessPickles said:

Found the problem...
The right header was resting against the head of one of the center stand mounting bolts. I swear I checked everywhere for contact like this when I installed the headers, but it was only visible from a certain angle (requiring my head to be completely under the bike to see the problem). I used a dremel to grind the edge of the bolt down to gain some clearance, then stuck a piece of an adhesive velco strip (the soft curly portion of the velcro) on both center stand mounting bolts on the right-hand side of the bike to dampen any possible contact with the pipe if the pipe vibrates enough to touch the bolts. The noise is gone and I hope the velcro stays in place.

Click to expand...

a dab of high temp silicone rubber a btter choice here?

ctfjr said:

a dab of high temp silicone rubber a btter choice here?

Click to expand...

I thought of that after I had put everything back together. Next time I have an excuse to take the fairing off again (or when I'm bored on a rainy day), I'll replace the velcro with silicone. I've reinstalled these headers quite a few times now trying to fix various minor issues; I'm beginning to wonder if I should have new header gaskets on hand for the next time...

Looks like I called this one solved a bit too early. I'm not sure what caused me to not hear the buzzing sound on my first test ride (maybe the earplugs...), but the buzzing sound is still there.

At this point, I've completely removed and reinstalled the entire exhaust system. I was very careful to hold the headers steady and flush while finger-tightening the mounting nuts (alternating between the two nuts for each header to ensure that the bracket was flush against the lip of the header pipe). I then tightened down all the nuts just a little bit at a time, alternating to ensure that the two nuts on each header were equally tightened. I have now completely ruled out the possibility of the pipes vibrating against anything (all center stand mounting bolts/nuts have been ground down as necessary). I also used high-temp silicone when installing the mufflers to ensure a good seal and to rule out the possibility of rattling at that connection point.

I also went for a ride with ALL of my items removed from the glove box and under the seat; the buzzing sound remains. The sound still seems to be coming generally from in front of me and down, but it's quite difficult to locate the source of a sound when riding. I suppose it could be some random loose fastener somewhere on the bike that will drive me crazy until I find it.

I've got this with Dale's stainless pipes, but didn't have it with the silver ceramic coated jobs.

It doesn't sound like an exhaust related thing and yet I know it started with the ss headers. When I installed Dale's new headers I was inspired by Mr. Webby to butcher my 05s airbox. I thought the noise was the result of that.

It's a new high pitched sound coming from the engine. :blink: