Wednesday, 29 January 2020

QR50 - Cleaning Poster Paint

Most of the QR action this week has been focused on buying material for the forks and gently cleaning the red poster paint off the parts.

The bodywork, mudguards and tank are made from polyethylene. You can determine what it is if you burn a sample - polyethylene smells of candle wax when you burn it. This is very difficult to paint successfully because it is so flexible, and cleaning the red poster paint off the parts (with soap and water in the kitchen sink) reveals green acrylic paint underneath, which is stuck except where the material flexes.


Therefore, the plan is to strip the green paint with Synstryp and polish it up with wet and dry. The front mudguard has had some of this treatment (it's up to 400 grit so far) and is looking much better:


Since I took this picture, I have removed the strain mark with heat.

The outer transmission cover is the next candidate:


Again this comes up well, and reveals that it still has the red stripe stuck on:


The bars and the seat are next, along with the bodywork which includes the side covers and rear mudguard in one moulding. Unfortunately this moulding is both cracked and holed.


The front forks are completely shot. The stanchions are unusable; one of the main springs has rusted to dust and the other, and both the rebound springs are not far behind. Since these are unobtainable, I will be making a new set of forks. Meanwhile, I have cleaned up some of the smaller parts



Another area of activity, getting ready for clean up, is the wheels. Like many bikes that have been unused for a while, the tyres on this one are rock-hard and had to be cut off:


Next step is to get the wire brushes into contact with this paint to strip it off. At the weekend, I will pick up the fuel tank and start cleaning that up:



While cleaning the transmission cover, I had a look at the kickstart shaft in the spare Express transmission I have. This is the QR50 one:


Unfortunately, the Express one is very different - longer, bigger splines, bigger quadrant - so it looks like we will have to build this up with weld and machine it back...

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