FH - Seat Base Repairs

The FH kit came with the original dual seat, cover intact, which I dismantled:

There was some foam, some original, some replaced:

The top of the seat base was in very good condition:

Underneath, there is enough space for a sandwich or two and I toyed with making the seat lift up for a while - I even made some hinges to try it out but considering the options for locking I realised that I was on a crusade that would be neat, but wouldn't achieve very much. I put the idea away for another day.

The seats were originally retained with Spire clips and screws, fastened from underneath before the oil tank was fitted - you cannot get to all the screws with the oil tank in place. Most of the holes for these had been damaged over the years, some severely.

As you know, I'm not a cheque book restorer and I hate throwing things away, so I resolved to repair the seat base. Since the Spire clips are not available and were meant to aid rapid assembly - no need for a separate operation to fit weld studs, for example - I decided to repair the holes with small plates with weld nuts.

I cut the holes out with a thin cutting wheel in the Dremel.

Another pet hate is mixed fasteners on bikes - so no metric bolts here, and no Unified series either. While it crossed my mind to make some proper weld nuts out of square bar, I decided no-one would ever see them and opted for off the shelf full hex nuts instead, 5/16" CEI.

I made all the plates and fitted them to the holes I had cut, labelling them A-D, before I drilled the holes for the nuts. I fixed one in place with duct tape and tried it on the bike, marking the bolt position from underneath. I drilled the hole, welded the first nut in place and tacked the plate to the seat base.

Refitting the seat base to the bike, I repeated the process with the second bolt, then the third and fourth so that at each step I could be sure the seat was in the right place and the bolts all fitted.

With them all done, I completed the welding. The metal is about 1.0 mm thick (20 SWG or so) and the SIP HG1800 DC TIG machine was set to 20 A. These are generally autogenous butt welds but I used some filler wire in places.

Not too shabby. There's a bit more to do at the back - those curved closing plates are holed but more of that later.