Possible cure for the vibrating licence plate

bosco659

bosco659

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Posted earlier this year - the licence plate on my ‘76 XS650C cracked at the mounts because of vibration. Tried various ways of stopping the plate from rattling around. By the end of the season I just let it shake away. While working on our 2011 Subaru Forester this fall, I stumbled on a vibration isolator that I thought may be the magic pill for the shaky plate. Ordered a couple and test fitted today. Fit was great and fingers crossed the plate will shake no more.
Here’s a few pics of the mounts and test fitting.
Note I have a 3/16” aluminum reinforcing plate attached to the back of the plate (with body panel bonding adhesive) to hold it together after cracking.
 

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Machine said:
Familiar light, familiar approach.
:thumbsup:
Click to expand...
Machine, I had isolated mine like yours but, my fender extends further past the light bracket and at 3500 to 4000 rpm, the bottom edge of the plate would rap on the fender with a real annoying noise, like something in the engine was coming apart. I had purchased other isolators like this on eBay and the rubber was considerably stiffer than these ones and they did not dampen the vibration sufficiently. Hoping this works!
 
I've been 4 bolting my plates to an aluminum backing plate with some sheet rubber sandwiched in between for many years now. I've never had any of my plates break .....

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I got my solution from the late RobinC - he simply bought / found an old truck mudflap and cut a slice off it.

One edge of the mudflap is bolted to the license plate bracket and the license plate itself is bolted to the other edge and all of the joints use fender washers.

Robin was kind enough to give me a chunk of the mudflap and so I have enough for my three XS650s (although I don’t know why I would need them as these bikes hardly vibrate at all....:lmao:)

2FD07CC3-6809-4AA6-BBB0-57DF210B2123.jpeg
 
MaxPete said:
I got my solution from the late RobinC - he simply bought / found an old truck mudflap and cut a slice off it.

One edge of the mudflap is bolted to the license plate bracket and the license plate itself is bolted to the other edge and all of the joints use fender washers.

Robin was kind enough to give me a chunk of the mudflap and so I have enough for my three XS650s (although I don’t know why I would need them as these bikes hardly vibrate at all....:lmao:)

View attachment 181792
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I like that idea too. Trouble for me is the location of the taillight relative to the fender. The edge of the plate lays right on the fender. Rubber could work though. Maybe I’ll go and buy a mudflap. They aren’t so expensive and I could use pieces of it for other projects. I used to have mudflap pads under my work bench legs. In the pic you can see where the edge of the plate is relative to the fender. Isn’t touching in this pic because I put a rubber bumper in the center of the plate, that rests on the fender. The rubber bumper was too hard so this didn’t work really well.
C629AFB8-D0B4-49C0-A1E8-BCF394F40686.jpeg
pads under my workbench legs.
 
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The mudflap is pretty thick Bosco - it causes the license plate to stand-off a good 6 mm (1/4 inch).

It is a dead simple idea and it seems to work well. Lucille has been run right up to....well, pretty danged fast - and no problemo after about 12,000 miles...(around 19,300 km).
 
MaxPete said:
The mudflap is pretty thick Bosco - it causes the license plate to stand-off a good 6 mm (1/4 inch).

It is a dead simple idea and it seems to work well. Lucille has been run right up to....well, pretty danged fast - and no problemo after about 12,000 miles...(around 19,300 km).
Click to expand...
Wish I had tried this before I paid $20 for my Subaru parts. Lol.
 
MaxPete said:
The mudflap is pretty thick Bosco - it causes the license plate to stand-off a good 6 mm (1/4 inch).

It is a dead simple idea and it seems to work well. Lucille has been run right up to....well, pretty danged fast - and no problemo after about 12,000 miles...(around 19,300 km).
Click to expand...
Already messaged a friend who I think can supply me with a mud flap Still need to test the Subaru bits first since I have invested heavily into them. Lol.
 
Years ago.. a buddy I was do'n Yellowstone.. Black Hills... Devil's Tower....... he on a Kz750 and I'm on my 82' Xs650. We left Custer 2nd Place state park and headed to Deadwood.... back road through the Indian reservation.... our average speed was 75 mph.. needless to say that stupid Special gas tank was get'n sucked dry pretty darn quick. Got to the motel in Deadwood and.. what ? My license plate.... all that was left was the top one inch " MINNESOTA ".... the rest is somewhere in Montana... If yer ever in SE Montana... keep a eye out for it.... ;)
 
plate , old plate a bead of silicone around the perimeter bolt together at bottom corners and to bracket, and happy new year. Many XS's, many miles.
 
motormike said:
Years ago.. a buddy I was do'n Yellowstone.. Black Hills... Devil's Tower....... he on a Kz750 and I'm on my 82' Xs650. We left Custer 2nd Place state park and headed to Deadwood.... back road through the Indian reservation.... our average speed was 75 mph.. needless to say that stupid Special gas tank was get'n sucked dry pretty darn quick. Got to the motel in Deadwood and.. what ? My license plate.... all that was left was the top one inch " MINNESOTA ".... the rest is somewhere in Montana... If yer ever in SE Montana... keep a eye out for it.... ;)
Click to expand...

Yup, I was on my 1975 XS650B in about 1978 when, stopped at a traffic light, an OPP copper pulled up behind me in his Dodge Polara holstein. Being a snotty young enginering student (is there any other kind?) on a rather loud motorcycle, I immediately got nervous and I nearly crapped myself when he put his cherries on and climbed out of the car and walked toward me with something in his hand.

It was the 96% of my license plate that had fallen off on Hwy. 2 near Bath Ontario. He saw it fly off my bike and stopped to pick it up - and then he chased me back toward Kingston so that he could give it back to me.

He said, “I think you’ll need this son - just in case we ever need to have another conversation.”

I was good boy, for the remainder of the day.
 
bosco659 said:
Longer fender gets in the way for me.View attachment 181793
Click to expand...
Another way to use some thick mudflap material might be to cut a piece to the exact shape of the rubber gasket between the fender and taillight housing and use it to space the housing itself further away from your fender - that would gain you a bit more clearance along the bottom edge of your plate and might not look so "standoffish" as the Subaru bits.
 

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