After quite a break I thought id come back and update this topic now I've made some progress
After being completely stripped down and refurbished to the best of my fairly limited ability she's all back in one piece at long last!
The list is as follows:
Wheels have been refurb'd ; hubs and spokes have been wire brushed then primed and sprayed matt black. Rims have been cleaned up best as possible and the whole kaboodle lacquered.
Front hub had its brake cable guide snapped off, so I fabricated a new one, ground the old one off and then tig'd that back on. Once smoothed over it was passable as being forged as one so I was quite happy with that!
Rear swingarm was removed and inspected, on the right have side it had rotted / rusted through so I patched it with some 4mm plate. Mig'd this on and ground her back. This sub frame was then painted with white hammerite, along with the rear brake arm.
The tank had one massive dent near the filler cap that had originally been filled, but the rust had pushed itself underneath and started to displace the filler. There was another serious dent on the corner near the rad, probably 3/4" deep. Bit of a learning curve here, I decided to fill it all in with Isopon P38, my first experience with filler. I was really pleased with the final result.
The crowns were removed and sprayed black, along with the bars and other smaller parts. Also bought some new A2 stainless 6mm m8 hex bolts to remove the rusty old 13mm sockets originally used.
I also took the forks out, wire wool'd the lower legs back to a nice polished alloy finish and lacquered these. The stanchions were cleaned with autosol and aluminium foil.
Mechanically the bike was actually fairly sound, all that was really needed was the unseizing of the bottom end and a good clean of the plug, piston and top end.
The rear brake pads literally dropped off their backings, probably due to the water exposure. Because of this I ended up buying some more pads, put these new ones in the front hub and the older front pads back into the rear. Of course, the drums were sanded out prior to this.
Happily I managed to beg some cables off my boss and one of the students at my work, new clutch and front brake cables certainly helped with the feel of the bike.
The throttle cable was actually knotted instead of having a barrel end to attach to the throttle itself. I ended up making a new end out of some 3mm bar stock, drilling a 1.5mm hold and soldering it to the end. Felt a fair bit safer.
Front and rear axle spacers were really badly rusted, so I just made some more on the lathe at work out of some ally lying around
The exhaust guard was a home-made affair as im sure you guessed It certainly works well, even if it isn't the prettiest thing around.
The rear exhaust was an old dep sport can that I scrounged off a mate, I then bent some 30mm 14 gauge ally tubing to match the DT frame. This was then TIG'd to the dep endpipe, I ended up packing the exhaust with washed loft insulation so we'll see how well that holds out. It certainly quitened the bike down massively
To summarise, the bike actually runs really quite well now and ive had a fair bit of fun on it. I've definitely learnt a hell of a lot already.
I could do with some help tuning her up to get the most out of it! The engine will only start on choke, and when revved will stammer and bog down. If you carry on blipping the revs it will rev right up on the third go? Quite strange, obviously something to do with the mixture screw. Id appreciate any advise on this matter!
Total so far is £12 on paint, and £26ish on parts
After a lot of attempting to start the Dt it became really apparent that it wasn't having any of it! Luckily after some trawling around on Ebay I managed to find a whole front exhaust / expansion chamber for £12 posted. Pretty much as soon as I put this on the bike came to life happily. Lots of patching needed for it though, probably 1.5 hours with the mig, burning away the old shitty metal until i reached the decent stuff. The exhaust had 4 large splits in it, 3 large holes and too many small holes to count!
As a temporary fix it's just been hammerited to give it some protection for the mean time. It will be resprayed with heat proof ( bbq i think ) if / when the hammerite has deteriorated.
A haynes manual is a definite necessity, and something i'm going to buy off the Bay as soon as I get round to it. I ended up using silicone sealant for the water pump sealing, and just used the original gaskets elsewhere.
She was a bit of a state! I really should have clarified this is a field bike only, even i'm not as ambitious as to try and get this beast on the road .
Not trying to disagree with you or anything, but I did actually end up filling the lower end of the engine with old 2 stroke and left it for a day or so to let it soak in. After that I literally flipped the whole bike up on end, crowns and seat down, wheels up to let all the oil and coke drain into a container. Result: one free bottom end
I did do this also, to try and circulate the oil, In the end all it needed was the extra backpressure from the exhaust it seems.
Im the first to admit that most of my "knowledge" is made up of guesswork and i do appreciate everyones concern about this being a very probable money pit Ive really tried to be careful with everything ive spent on her, and I think ive done pretty well so far.
Im based in Cornwall, PL22 0LW. Anything that could help would be amazing, particularly looking for plastics now I think. Also a rear wheel, as the rear rim is fairly shot from corrosion.
It certainly is for the field, and I did have a fairly strong spark from the off which certainly helped matters! Dt's do seem to be fetching a fair price on the Bay and in classifieds, so I think it was probably worth fixing her up .
Anyway, I hope you guys like the pictures of her...hopefully I'll get some graphics made for it soon.