I hate doing bodywork. I am not very good at it, it takes far too much time and it’s just not nice. I knew the tank was going to be a challenge as it had a massive dent in it and several smaller dents, the paintwork was really bad with lots of flaking and it really needed to go back to clean metal. I tried pulling out the largest dent but that was only moderately successful and plenty of filling and fettling was still required. I won’t bore you with the details, it took a couple of days of work to get it how I wanted it and it’s still only in primer. The inside is proper crusty and I know I have a couple of small pinholes. I am therefore going to use electrolysis to derust the inside and will then use a lining solution to make sure it doesn’t leak, only then will it get the top coats of paint.
I have used electrolysis a lot in the past and it’s a perfect process for the inside of a tank as it will get right in to every part and deep in to the seams. It takes a fair while – about 12 hours for heavily rusted parts but it’s by far the best way and it doesn’t remove any healthy metal. I have ordered soda crystals on line to make up the electrolyte – some people use salt but as salt is corrosive I don’t like it. I have no idea if the soda crystals are also corrosive but I have always been very happy with the results when I have used them in the past. It’s very cheap to buy, a 1 kilo bag costs a couple of quid at the time of writing this (February 2021) so it’s much cheaper than any proprietary rust preparation.
For now I have put the tank on the bike to keep it safe while I do other things, next on the agenda is the front forks.
You will have noticed that I now have the engine in place in the frame, I love these little bikes where you can lift the engine with one hand, the big fours are so much heavier and cumbersome. There are only 3 bolts that hold this one in. You put the rear most one in first and then lift the front of the engine slightly until the front bolt goes in, then do the bottom one. Hey presto – 5 minutes work and the engine is in place – no swearing needed.
The seat is a replacement I got from on line as mine was way beyond repair. I have also fitted the repaired clocks and both stands. The shocks are new, once again it proved impossible to find decent originals that were good enough for the job. These ones look fine, time will tell how well they actually work, better than any 36 year old leaky old knackered ones, I suspect. The engine is a lot shinier than it looks in the photo, it’s a really cold, wet day and everything has a thick layer of condensation on it, I will take more when the weather clears up a bit.
I have ordered the fork seals so while I await their arrival I shall put some of the other restored bits back on to the bike and assess a few more parts – the fuel tap being the main one. I have no idea if it works but strongly suspect that it doesn’t, I also suspect something will break when it comes apart so a service kit is a necessity. The taps on these are vacuum operated and it’s quite common for the vacuum diaphragm to split or leak, it’s also common for the plunger that controls the fuel flow to stick. They are a bit fiddly but quite easy to sort out, repair kits are still easy to obtain.
In the meantime I cut the front hubs out of the wheels – the rims and spokes are beyond saving and the tyres are both shot so the hubs are the only usable parts. It gave me a great opportunity to use the blast cabinet I bought at Normous Newark back in the Summer – one of the very few jumbles we actually made it to. It did a great job although I need to buy more blasting medium for it as the pickup pipe kept sucking air, which was rather annoying. The medium needs to be quite deep to ensure a constant flow to the gun. Anyways now I have to source rims and spokes – I suspect that will see my wallet lightened by about 300 quid and I will still need tyres. Bugger.
While I was in strip / clean mode I took the rear sprocket off the carrier and cleaned all that up – the sprocket looks to have had hardly any use, which is a bonus, a quick clean up, some paint and it all looks fine and dandy. The carrier got cleaned and polished a bit – I didn’t go too mad on it as it will only get chain oil / wax on it the first time it is ridden anyway. The rest of the hub has been cleaned up to match, I have worn out the wire brush on my bench grinder so I will have to wait a couple of days for a replacement to arrive before any more wire brush based frivolity occurs.
The other bits that arrived were some nice shiney new stainless acorn nuts for the shock absorbers. These things sell for about 15 or 18 quid a set if you buy them as bike specific items but if you go to a decent supplier and ask for 10mm x 1.25 fine thread acorn nuts you will get 6 delivered for less than a quid each – 4 are required. This sort of thing boils my piss – I found the same thing with chains. If you search for a GT250 chain (520 102 link) you will find plenty of people selling them at 60 to 80 quid. You can buy exactly the same item for about £25 so don’t go spending more than you have to. Do go for a decent make though, a snapped chain is not funny, they can do a lot of damage to you and the bike so stick with reputable makes but don’t over pay for them.
I also received my new cables from Wemoto – just the tacho and throttle cables at the moment, they also serve to prove my point. On a well known on line auction site I saw a used throttle cable that somebody was asking 45 quid plus post for!! A brand new Slinky Glide top notch cable from Wemoto – just £15.95. And it arrived the very next day. It did however raise another problem as I realised the adjuster for the oil pimp is missing. I have very little chance of finding one so I will make one with my model maker’s lathe. It is a simple turning job and I quite enjoy such things.
With all the rear hub parts now polished I wanted to keep them safe so I reassembled the rear temporarily. It’s all looking rather nice now. I guess I should get the spokes and rims on order.
Article provided by David Powell of Boston Bike Bits.
