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Delkevic exhaust - vibrations?

cafet100

cafet100

Mini Bike
Hi I just fitted an oval 18" Carbon fiber to my concours 2013. Took it out for the first time today and I notice that there is vibration on the bike that was not there before. Goes through the rev range. It is not even close to touching the frame anywhere and it only has the one mount unlike the stock which has 2. The little extension tab is connected to the original bolt in its rubber mount.

Has anyone else noticed this vibration? The exhaust note is not loud even with the baffle out but being so light the muffler could transmit vibration into the frame where the standard muffler would dampen it out.
 
Pat,
The delk exhaust will make a noise similar to a vibe if you do not put a bolt in the hole normally used for mounting the baffle. Mine did until I put a bolt in the hole. No "vibes" though on mine. Same 18' CF oval.
Matt
 
mattchewn said:
Pat,
The delk exhaust will make a noise similar to a vibe if you do not put a bolt in the hole normally used for mounting the baffle. Mine did until I put a bolt in the hole. No "vibes" though on mine. Same 18' CF oval.
Matt
Click to expand...

+1

I also didn't have mine seated all the way on the header and the rubber wasn't lining up...it was Christmas morning!  :)
 
mattchewn said:
Pat,
The delk exhaust will make a noise similar to a vibe if you do not put a bolt in the hole normally used for mounting the baffle. Mine did until I put a bolt in the hole. No "vibes" though on mine. Same 18' CF oval.
Matt
Click to expand...
so just blank off the hole? Everything went together fine and sealed with copper silicon sealer. They actually provided a tube of it but I already had one open. Without the baffle it is not loud in any way.
 
mattchewn said:
Pat,
I just put a screw and nut in there to close it off. Worked perfect.
Matt
Click to expand...
yup - I put a stainless domed cap screw and it improved the sound but there is still vibration through the seat and the handgrips that was not there before. Has to be the light weight of the box and the acoustics.
 
Pat,
I would recheck that the mounting is not too tight/ steep angle and constricting the movement of the insulator bushings for the muffler hanger. Can't think of anything else other than maybe a loose part inside the can? Rubber grommet in place on the stubby bracket for the center stand?
Matt
 
mattchewn said:
Pat,
I would recheck that the mounting is not too tight/ steep angle and constricting the movement of the insulator bushings for the muffler hanger. Can't think of anything else other than maybe a loose part inside the can? Rubber grommet in place on the stubby bracket for the center stand?
Matt
Click to expand...
No it is all good. Nothing under stress. Has to be acoustics. It is no big deal but it is there.
 
I'm going to put a screw in the empty hole this AM.  I have it too...not awful at all, but there, and I thought it was just vibes from the sound...  interesting.
 
wyomingpat said:
mattchewn said:
Pat,
I would recheck that the mounting is not too tight/ steep angle and constricting the movement of the insulator bushings for the muffler hanger. Can't think of anything else other than maybe a loose part inside the can? Rubber grommet in place on the stubby bracket for the center stand?
Matt
Click to expand...
No it is all good. Nothing under stress. Has to be acoustics. It is no big deal but it is there.
Click to expand...
i fitted a rubber grommet on the bolt that secures the muffler strap and that fixed it.
 
wyomingpat said:
wyomingpat said:
mattchewn said:
Pat,
I would recheck that the mounting is not too tight/ steep angle and constricting the movement of the insulator bushings for the muffler hanger. Can't think of anything else other than maybe a loose part inside the can? Rubber grommet in place on the stubby bracket for the center stand?
Matt
Click to expand...
No it is all good. Nothing under stress. Has to be acoustics. It is no big deal but it is there.
Click to expand...
i fitted a rubber grommet on the bolt that secures the muffler strap and that fixed it.
Click to expand...

:great:
 
cafet100 said:
i fitted a rubber grommet on the bolt that secures the muffler strap and that fixed it.
Click to expand...
Hey bud, can you send a pic of what you did to correct the vibration you had with your new Delkevic slip-on? I think I am experiencing the same thing you were. You mentioned a rubber grommet on the bolt that secures the muffler strap? Thanks! -Heath
 
HeathCreek said:
Hey bud, can you send a pic of what you did to correct the vibration you had with your new Delkevic slip-on? I think I am experiencing the same thing you were. You mentioned a rubber grommet on the bolt that secures the muffler strap? Thanks! -Heath
Click to expand...
Heath just an expectation check here, @cafet100 has not been on the site in 7 years - older posting. Maybe someone else has done the same thing and will share but I would not expect Pat to chime in.

FWIW I believe what Pat was talking about was putting a rubber grommet / rubber bushing in-between the strap that holds the muffler and the frame.

Wayne, Carol & Blue
 
2andblue said:
Heath just an expectation check here, @cafet100 has not been on the site in 7 years - older posting. Maybe someone else has done the same thing and will share but I would not expect Pat to chime in.

FWIW I believe what Pat was talking about was putting a rubber grommet / rubber bushing in-between the strap that holds the muffler and the frame.

Wayne, Carol & Blue
Click to expand...
Thank you, Wayne! I wonder about how thick a bushing and if I probably need a longer bolt to compensate for it. Thoughts?
 
Look here
Think Wayne is talking about something like this. If you're going to put a bushing through the grommet, it would need to be thinner than the rubber grommet or the grommet isn't going to help your problem. HTH
 
Bud said:
Look here
Think Wayne is talking about something like this. If you're going to put a bushing through the grommet, it would need to be thinner than the rubber grommet or the grommet isn't going to help your problem. HTH
Click to expand...
Exactly, need to isolate the vibrations from the frame.
 
2andblue said:
Exactly, need to isolate the vibrations from the frame.
Click to expand...
Thanks
Bud said:
Look here
Think Wayne is talking about something like this. If you're going to put a bushing through the grommet, it would need to be thinner than the rubber grommet or the grommet isn't going to help your problem. HTH
Click to expand...
Thank you. Can you send me a picture of a bushing, to make sure what you are referring to as a bushing and what I am thinking of a bushing is the same thing?

I added some rubber washers here, but I havent had a chance to test it at highway speeds yet.

Top and bottom bolts of hanging bracket
20230611_105505.jpg

Put rubber washer here at top bolt (original stock muffler holder bolt)
20230611_105410.jpg

Put rubber washer on both sides of lower bolt of hanging strap bracket
20230611_105313.jpg

20230611_105227.jpg


I figured this should work the same as a grommet?

I hope this works. Bike had zero vibrations with stock exhaust. More suggestions and advice welcome. Maybe this can help someone else, too.

-Heath
 
I think y’all are fixing a non issue. Do you really think that little extra washer is going to kill vibes that the stock damper mount isn’t going to kill? And how much vibes do you get from carbon fiber? In order to dampen vibes the bolt needs to be fully isolated from the strap. That means rubber through the hole of the strap so there’s no metal to metal contact, like the stock isolation mount. Why don’t you wait and see if it vibes before you fix something that ain’t broke?
 
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Steve in sunny Fla said:
I think y’all are fixing a non issue. Do you really think that little extra washer is going to kill vibes that the stock damper mount isn’t going to kill? And how much vibes do you get from carbon fiber? In order to dampen vibes the bolt needs to be fully isolated from the strap. That means rubber through the hole of the strap so there’s no metal to metal contact, like the stock isolation mount. Why don’t you wait and see if it vibes before you fix something that ain’t broke?
Click to expand...
It vibes, that is premise of the thread. Trying to resolve it. For this reason I came for advice. Not sure what you mean in your post regarding a non-issue or fixing something that isnt broke , and we have already agreed that I need to eliminate metal to metal contact. At this point, just looking for the best method to do that. In my original reply to this thread, I was just looking for some clarification from Cafet100 who said:

"i fitted a rubber grommet on the bolt that secures the muffler strap and that fixed it."

That is how he fixed the vibration. I want to do the same thing to fix the same issue he had. However, since he is no longer active on the forum, a few other nice gentlemen have stepped in to try and help me. Not sure if you read the whole thread or not or what little extra washer you were referring to. I did add some thick rubber washers at all contact points with metal, since I dont have any grommets right now, of that is what you mean. I dont know if it is going to work, but that is what I had, and my attempt in fact was to eliminate metal to metal contact...hence the rubber washers. I will go find some grommets tomorrow.
 
HeathCreek said:
It vibes, that is premise of the thread. Trying to resolve it. For this reason I came for advice. Not sure what you mean in your post regarding a non-issue or fixing something that isnt broke , and we have already agreed that I need to eliminate metal to metal contact. At this point, just looking for the best method to do that. In my original reply to this thread, I was just looking for some clarification from Cafet100 who said:

"i fitted a rubber grommet on the bolt that secures the muffler strap and that fixed it."

That is how he fixed the vibration. I want to do the same thing to fix the same issue he had. However, since he is no longer active on the forum, a few other nice gentlemen have stepped in to try and help me. Not sure if you read the whole thread or not or what little extra washer you were referring to. I did add some thick rubber washers at all contact points with metal, since I dont have any grommets right now, of that is what you mean. I dont know if it is going to work, but that is what I had, and my attempt in fact was to eliminate metal to metal contact...hence the rubber washers. I will go find some grommets tomorrow.
Click to expand...
I'm sorry, I'm new around here? I'll try to catch up.

I wonder though... have you tried loosening all the bolts and the clamps, rotating or shaking the muffler / midpipe so that any stress or tension from misalignment is resolved, and then carefully tightening the fasteners? I notice in the pic the muffler looks really close to the rear wheel linkage. it could just be the angle, forgive me if I'm wrong. I do notice that about 95% of these bikes have slip ons and delkevic seems to be the most popular, but there don't seem to be alot of threads with folks dealing with vibration from a new installation. I also see what appears to be metal to metal contact of the muffler strap to the extension bracket so there's no isolation at that point, nor of the bolt going through the hole. Just an observation. Please ignore anything I say if you find it useless or offensive.
 
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Steve in sunny Fla said:
I'm sorry, I'm new around here? I'll try to catch up.

I wonder though... have you tried loosening all the bolts and the clamps, rotating or shaking the muffler / midpipe so that any stress or tension from misalignment is resolved, and then carefully tightening the fasteners? I notice in the pic the muffler looks really close to the rear wheel linkage. it could just be the angle, forgive me if I'm wrong. I do notice that about 95% of these bikes have slip ons and delkevic seems to be the most popular, but there don't seem to be alot of threads with folks dealing with vibration from a new installation. I also see what appears to be metal to metal contact of the muffler strap to the extension bracket so there's no isolation at that point, nor of the bolt going through the hole. Just an observation. Please ignore anything I say if you find it useless or offensive.
Click to expand...
Those are all really good points and suggestions, Steve. Thank you! I will take a look at all these things. I will let you guys know how it goes!
 
Fixed! My rubber washers as.pictured previously fixed the vibration issue! Very happy! Thank you all for your advice along the way! For good measure I went and added a grommet to the bracket as well where the bolt goes through. Unbelievable how some very small metal to metal contact points like that can create vibrations throughout the entire bike!20230612_095807.jpg20230612_095746.jpg
 
Glad you got is solved, must isolate any metal to metal contact otherwise the acoustics and other vibrations will go straight into the frame.

Good Work, enjoy!

Wayne, Carol & Blue
 
We got some sensitive butts, must be running a corbin seat...!! Lol. Cuz we all know how much padding those seats have....btdt
 
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