Rear Fender Rattles

[Slayer69]

I recently completed my Frankenstein Trike kit install on my 2015 street glide. Everything went fine. Got the fenders back from the paint shop and installed them and now have a loud rattle in the back fenders that starts at about 3000 RPM but eventually settles out when the speed stablizes.

I've checked my motor mounts, all the bolts on the kit are torqued to spec. I can grab the fender brackets and that reduces the vibration to the point that the fender no longer rattles. Not sure what else to look at. Hoping someone on this forum has an answer or suggestions.

 

[Papa Zook]

Slayer,
I've built a bunch of the Frankenstein trikes and I cant say that I have run into a rattle like you describe.

Take a look at the swingarm bushings and proper install, that would be the first place Id look. If that all looks good, than check your shock mounts/bushings. You're going to have to track it down, but you'll find it.

 

[michea3]

Have you found the issue .I have the same on my roadking .installed a Frankenstein trike fenders rattle everything is tight

 

[Slayer69]

Have you found the issue .I have the same on my roadking .installed a Frankenstein trike fenders rattle everything is tight

I have not yet found the problem. Like I mentioned above, I've checked everything. I also tried rubber washers, brackets inside the fenders but nothing helps. My next thing I'm going to do is replace all the motor isolation bushings and the stabilizer link. I'll post in here how that goes.

 

[michea3]

Okay I think I got it . I made extra brackets made out of 2-1/8 steel plate that stiffened up fenders on mounting side .then I took a piece of rubber hose black the diameter of the fender bracket that runs on the top, then took two stainless hose clamps put it around that top fender bracket .and connected to the aluminum shaft now I'm riding with no more rattles nice and quite ..

 

[Slayer69]

Okay I think I got it . I made extra brackets made out of 2-1/8 steel plate that stiffened up fenders on mounting side .then I took a piece of rubber hose black the diameter of the fender bracket that runs on the top .then took two stainless hose clamps put it around that top fender bracket .and connected to the aluminum shaft now I riding with no more rattles nice and quite ..

That's great that you found the problem and have a fix. Could you post a couple of pics of that fix or shoot me an email? I'll try anything at this point. Thanks!

 

[michea3]

I can try to take pictures or draw up a drawing what I did then take a picture then send it to you .my email is
sporsterman1@hotmail.com
Thanks

 

[Papa Zook]

It would be great if you can post your pictures here, so others with this problem can learn.

 

[michea3]

It would be great if you can post your pictures here, so others with this problem can learn.

Please email- me ...according to Frankenstein they never ran into this issue to me it's a bad design on the fender mount for our bikes so what I came with was a dampening system I'll be glad to do it for you in an email just contact me there ....

 

[Papa Zook]

I can't say that it's a bad design, too many happy Frankenstein Trike owners bragging on them. I have not had a rattle on any of the ones I have built and if it were a design issue, Frank would have addressed it.. I did have one that just did not want to track straight, but haven't had a fender rattle. I searched every thread on this forum and couldn't find another fender rattle issue posted. I feel it is more likely a worn motor mount that is the root cause and stiffing up the fender braces is helping alleviate the rattle but not the cause. After Slayer69 changes his motor mounts and stabilizer link we'll see if that cured it.

 

[michea3]

Well I agree it is a nice system but there is a flaw in the mount I am a machinist by trade we have engineers by me not always perfect always asking us for improvements.lol any way two other people are having the same issues with the fenders rattling always motor mounts??

Big fenders not much of mounting surface called Frankenstein he suggested to paint inside of fenders with rhino bed liner really???. And it's not my motor mounts .think about where the bolts mount on the fender mount the top brace of the fender mount is the one that's causing the fenders to rattle especially in the lower power ban get above 60 goes away for the most part . found out the problem fixed it for about 32.00 in material now I am happy figured I spent 8200.00 shouldn't have gone thru this or maybe should have gotten a motor trike kit just saying ....

 

[Slayer69]

Please email- me ...according to Frankenstein they never ran into this issue to me it's a bad design on the fender mount for our bikes so what I came with was a dampening system I'll be glad to do it for you in an email just contact me there ....

I sent you an email yesterday. I have had many conversations with the Frankenstein guys and they do not acknowledge this as a problem but if you look at their site, most of the trikes have the shorter fenders. I'm anxious to see your fix. Thanks.

 

[harmon87]

Got a 04 ultra classic with frankenstein trike kit on it. Fender rattle like crazy take them off all my rattle goes away when I put them back on it goes to rattling. Anything I can do to fix it.

 

[Papa Zook]

What bike is the kit on and does it have the long or short fenders?

 

[harmon87]

2004 harley davidson ultra classic. The long fender

 

[Papa Zook]

I can try to take pictures or draw up a drawing what I did then take a picture then send it to you .my email is
sporsterman1@hotmail.com
Thanks

Sent you an email.

 

[Jack Klarich]

Well I agree it is a nice system but there is a flaw in the mount I am a machinist by trade we have engineers by me not always perfect always asking us for improvements.lol any way two other people are having the same issues with the fenders rattling always motor mounts??

Big fenders not much of mounting surface called Frankenstein he suggested to paint inside of fenders with rhino bed liner really???. And it's not my motor mounts .think about where the bolts mount on the fender mount the top brace of the fender mount is the one that's causing the fenders to rattle especially in the lower power ban get above 60 goes away for the most part . found out the problem fixed it for about 32.00 in material now I am happy figured I spent 8200.00 shouldn't have gone thru this or maybe should have gotten a motor trike kit just saying ....

Can you make a rubber isolator for the mounts?

 

[Papa Zook]

All Harley trikes have major vibration that shakes their fenders, not just the trike conversions, it's a function of a large displacement V-Twin engine. I've seen some Tri-Glides that are ridiculous.

 

[harmon87]

I have put rubber between fender and bracket still didn't help. I take fender off no rattle. Put them back on rattles like crazy

 

[Jack Klarich]

I was thinking out loud on this post, I used some rubber welting between my fenders and the body to isolate some of the vibrations

The Moco uses some tape between the fenders and the body during assembly @ the factory, this acts like a gasket

 

[Papa Zook]

I think the gasket does keep the two fiberglass surfaces from directly rubbing together, but I don't think there is anything that will totally cure it and so long as it doesn't have the annoying "rattle" it is not a problem.

 

[Slayer69]

I have not yet found the problem. Like I mentioned above, I've checked everything. I also tried rubber washers, brackets inside the fenders but nothing helps. My next thing I'm going to do is replace all the motor isolation bushings and the stabilizer link. I'll post in here how that goes.

Date: 7/24/2024: So...I've replaced the stabilizer link, front isolator bushings and rear isolator bushings and I still have the fender rattle. Next approach will be inside the fender brackets. If that doesn't fix it then I'll run with no fenders.

 

[michea3]

Hello if you contact me by email I'll email you a drawing on what I did to stop it .I just had a hip replacement a week ago getting around good . sporsterman1@hotmail.com..it's that bracket you are wasting your time and money changing all that stuff .they don't want to admit that bracket has to get redesigned for those bigger fenders ...

 

[Slayer69]

Hello if you contact me by email I'll email you a drawing on what I did to stop it .I just had a hip replacement a week ago getting around good . sporsterman1@hotmail.com..it's that bracket you are wasting your time and money changing all that stuff .they don't want to admit that bracket has to get redesigned for those bigger fenders ...

email sent. Thanks

 

[Slayer69]

Date: 7/24/2024: So...I've replaced the stabilizer link, front isolator bushings and rear isolator bushings and I still have the fender rattle. Next approach will be inside the fender brackets. If that doesn't fix it then I'll run with no fenders.

Date: 8/10/2024 - I cut some inside fender brackets and installed them and they did not fix the problem. However, I tried a somewhat similar approach that michea3 suggested but instead of using hose clamps to tie the bottom two fender bracket tubes to the rear axle I used ratchet straps and that did, in fact, stop the fender rattling. I haven't fully road tested it yet but I can tell you that I did not have the rattling like I did before. Kudos to michae3!