The member photo gallery is now integrated and live!!  All user albums and pictures have been ported from old gallery.


To register send an e-mail to admin@bmwr65.org and provide your location and desired user name.

Author Topic: Securing Speed Hump  (Read 1086 times)

luckyd20

  • Guest
Securing Speed Hump
« on: October 25, 2012, 11:17:25 PM »
I need some help trying to securing my speed hump on my cafe seat. I was able to secure the forward part but the speed hump vibrates and rubs at my new powder coated frame. What have you done to secure the rear portion? If possible post come pics.

Here is how my speed hump is sitting.



Offline Bob_Roller

  • Global Moderator
  • Mt. Olympus Resident
  • *****
  • Posts: 9125
  • -7 hours GMT
« Last Edit: October 25, 2012, 11:30:40 PM by Bob_Roller »
'81 R65
'82 R65 LS
'84 R65 LS
'87 Moto Guzzi V65 Lario
'02 R1150R
Riding all year long since 1993 .
I'll give up my R65, when they pry my cold dead hands from the handlebars !!!!!


Offline montmil

  • Mt. Olympus Resident
  • ****
  • Posts: 8371
Re: Securing Speed Hump
« Reply #3 on: October 26, 2012, 08:37:07 AM »
With the unfinished fiberglas seat bottom, you'd end up with a much more secure install by fiberglasing an attach bracket -or whatever you choose- to the seat pan. Design a way to secure the Adel clamps to the glassed-in-place attach bracket.

Swing by any West Marine ships store and get the epoxy resins and cloth you'll need. I avoid the vinyl-ester and poly stuff sold at the FLAPS. For the stress the seat pan will experience, I don't think JB Weld is the right choice.

BTW, I like and use JB for odd little jobs but definitely avoid it with my motorcycles. YMMV
Monte Miller
Denton, TEXAS
1978 BMW R100S
1981 BMW R65
1983 BMW R65
1995 Triumph Trophy
1986 VW Cabriolet

tvrla

  • Guest
Re: Securing Speed Hump
« Reply #4 on: October 26, 2012, 01:53:44 PM »
The seat hump has very little support from the pan. There's an edge for the front section, but none at the rear - it's been cut away. And that's where it's sorely needed!

There's no strength to align the hump to the seat part, and when you push your butt against it, it'll flex. It's like it's attached with a flexible hinge.

There are a couple solutions - glass in a rod tying the two sections together, or continue the vertical edge all the way to the rear. Myself, I'd beef it up and extend it all the way down to the frame.

Session101

  • Guest
Re: Securing Speed Hump
« Reply #5 on: October 26, 2012, 03:19:54 PM »
easy google search

http://kickwrench.com/2012/01/18/diy-wednesdays-how-to-mount-your-cafe-seat-for-5-in-5-minutes/

http://www.dotheton.com/forum/index.php?topic=22762.0

mainly i would get some rubber to wrap around the frame first then attach bolts wrapped around the rubber on the frame and bolt that to the seat, and you might want to have rubber washers on the seat and that should absorb more vibration

luckyd20

  • Guest
Re: Securing Speed Hump
« Reply #6 on: October 27, 2012, 01:02:24 AM »
Quote
easy google search

http://kickwrench.com/2012/01/18/diy-wednesdays-how-to-mount-your-cafe-seat-for-5-in-5-minutes/

http://www.dotheton.com/forum/index.php?topic=22762.0

mainly i would get some rubber to wrap around the frame first then attach bolts wrapped around the rubber on the frame and bolt that to the seat, and you might want to have rubber washers on the seat and that should absorb more vibration

I have the part where I sit on mounted. That's not the problem. The problem is where the hump is at. I don't have an edge on the bottom of the hump to do a mounting like this. I would have to come up with a bracket or something.

Offline montmil

  • Mt. Olympus Resident
  • ****
  • Posts: 8371
Re: Securing Speed Hump
« Reply #7 on: October 27, 2012, 07:20:17 AM »
Quote
... The problem is where the hump is at. I don't have an edge on the bottom of the hump to do a mounting like this. I would have to come up with a bracket or something.

Start sketching out some ideas to secure the bum stop area. As Wirespokes said, that area is going to flex, quickly develop stress cracks and ultimately fail. Even if your butt isn't planted back there, the road stresses will cause the rear of the seat to jump up n' down. I've noticed this situation on some cafed bikes at track days.

You may need to consider having some sort of cross-frame structure welded to the rear sub-frame as a secure mount for the aft portion of the seat. Even with an extended fiberglas skirt, that alone would not be enough support.
Monte Miller
Denton, TEXAS
1978 BMW R100S
1981 BMW R65
1983 BMW R65
1995 Triumph Trophy
1986 VW Cabriolet