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Old 25-09-2019, 11:38 PM   #1008
350TSS
Too much time on my hands member
 
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Join Date: Jan 2013
Location: Shipbourne
Bike: M900
Posts: 1,417
Not much actual progress today but I worked really hard.

First I cleaned up the excess CF from the number plate housing and, although it looks Ok and appears to be extremely strong for the weight, it is not quite square. I can probably finesse that in the mounting by spreading the un-squareness between the rear light position and the angle of the number plate, as the number plate will be more immediately visible the un-squareness will be largely lost on the lights. Annoying nevertheless as I spent some time trying to ensure it was square but it may have moved as I applied the second coat of resin and CF.
I then cut and trimmed the CF plate to pick up in the two truncated rear frame tubes which will act as a support for the rear light number plate mount.
Previously I had made the threaded plugs to go in the end of the truncated tubes, they were boxed up in a Chinese take-away box and I saw them last week whilst looking for something else, Could I find them now? About an hour was spent going through all the boxes (and there are lots of them). They seem to have vanished off the face of the earth. I went through the boxes a second time. I decided to make some new ones, this time a little larger in diameter as the old ones were just a tad loose when fitted to the frame tubes.

The rear frame tubes are nominally 18mm ID but the tubes are seamed so a precise ID is difficult to determine. The new bushes I made at 17.8mm OD for 22mm with a 5mm step at the end to the OD of the bar at 25mm OD. There is a longitudinal hole threaded 6mm.

The bushes started to go in OK with a little gentle persuasion from a soft faced mallet and got about 12mm in then stuck. A heavier 1kg soft face hammer was pressed into service with not inconsiderable vigour and they got to within 4mm of seating properly but would go no further. Bollides!!!!

So they had to come out, about an hour later they were out and then turned down again to 17.2mm and the damage inflicted on the flanges turned off. Finally they were driven home.

Over a cuppa I thought about the seat removal, the interface with the number plate unit and the frame and the wiring harness and realised that ease of removal was ultimately about reducing the number of interfaces. Also I considered the effect of the addition of the plate being attached to the frame and the seat/number plate unit. The conclusion was that any movement in the seat /number plate unit (caused by me moving around on the seat or descending heavily after hitting a bump) would cause compression loads on a 3mm thick sheet of CF and it would shatter/splinter over time around the bolt hole. Rubber mounting it would rather defeat the object of having the support plate. So best not bother after all and I now have threaded plugs in the frame tubes with 6mm threaded holes that I do not need.
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