Author Topic: My Cafe' Bump Seat install - cb550k  (Read 5288 times)

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Offline steam-powered man

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My Cafe' Bump Seat install - cb550k
« on: January 23, 2010, 11:12:35 AM »
Hello all,
I’ve received invaluable help on maintaining and operating these vintage rides over the past few years from this great site.  I hoped I could “give back” a little some day and from that perspective thought I’d share how I mounted my Roccity café bump seat on my ’77 550k.  This is a compilation of techniques found during my research and I’m hopeful that other ideas might result.  There are any number of ways to mount a café seat, and my particular needs were met using this method.  My intention was to have a seat that could flip up on a hinge, have a replaceable seat base in case I wanted to change the seat pad, be of bolted construction so parts could be replaced as needed, make it easy to fab using common hand tools (am not a welder) and to be rugged enough to stand up to my riding “style”.

First off, many thanks to roccitycafe.com for a quality product.  He fabs the seats on an as-needed basis, and the quality of the work in both fiberglass lay-up and gelcoat are superb.  The seat is straight, true, flat, well-finished and at $125 pretty reasonable in my view.

First I cut a template to fit where the seat would be mounted and when the shape was right cut the seat base out of 3/4 inch clear pine.  Two sides were beveled to match the curve of the inner seat, and all edges sanded.  Will be protected with spar varnish a little later.  

I spent maybe way too much time aligning the seat so that it’s perfectly located over the centerline of the bike and, in side-view, matches the horizontal lines of the fuel tank lower edge. A little Googling resulted in proper techniques for drilling thru gelcoat/fiberglass and this was accomplished with any cracking of either.  Phew!  The drilled holes for the hinge plates and seat base are a touch oversized, allowing for small changes in orientation when needed.  

I mounted the wooden base to the seat using 1/4inch bolts, with flat washers backed by rubber washers (to help absorb vibration).  The pin from a 6 inch heavy duty strap hinge was removed and the strap was thru-bolted to the seat base.  Am using a 1/4 x 5inch bolt for a hinge pin at present   The plate of the hinge was mounted on the opposite side and acts as a bracket for one of the bolts used to lock the seat down.    

The seat assembly is secured using a 1/4inch bolt/wing nut on the right side and another hidden under the seat front.  Access to the latter is by reaching in past the #4 pod.  A snug/cushioned fit was accomplished by using short sections of foam pipe insulation on the frame rails.  

The end result is a very stable base for the seat pad, to be fab’d this week.  This morning I picked up a small piece of dead-flat birch laminate ($1) at the local lumber yard.  Once cut to size, holes will be counter-sunk to receive the bolt-heads and I plan on using heavy-duty Velcro to attach the seat pad to the base.  I picked out some marine-grade vinyl ($7) in light brown (rather than black) and will fab a cushion shortly.

Following that will be a complete disassemble for painting the ‘glass (and tank), hoping to be ready by spring!    
« Last Edit: January 25, 2010, 11:30:43 AM by shoemaniii »
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Offline KB02

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Re: My Cafe' Bump Seat install - cb550k
« Reply #1 on: January 24, 2010, 05:13:34 AM »
Awesome. I have been bouncing around mounting ideas for my cafe seat from Rockcity racers. Now I have a much better idea of a place to start. THANK YOU!
1978 CB750K Project
2000 Ducati ST2
...and a pedal bike

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Offline RatFink84

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Re: My Cafe' Bump Seat install - cb550k
« Reply #2 on: June 12, 2010, 01:31:36 PM »
Which Roc City seat did you go with?

Offline Spikeybike

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Re: My Cafe' Bump Seat install - cb550k
« Reply #3 on: June 12, 2010, 01:51:04 PM »