TOPIC:

Forks:

I was expecting the worst having seen the mayonaise and water that came out of the fork so I started with the leg with less water in it



The damper is fine, looks sealed so I'll leave it alone. The rust on the spring and rod came off easily after dissembly with a wire brush.

Reluctant fork seal



Pulled out with much persuasion



Everything cleaned up in the parts washer. Seal replaced with Ari type 020, great fit and much nicer than Pyramid seals. Bottom nut on fork leg needs thin wall deep, straight socket probs more common in 1/4" drive. I used a hex screwdriver bit extension on the normal 1/4" socket I had that would fit and was lucky nothing snapped. Crush washers for bottom nut 7 x 14mm fit but 1/4" might be better.

The other fork leg was not so good but only a small area of corrosion on the active bit of the damper rod so I cleaned it up and reassembled. Decided to grease the steering head properly after remounting the fork legs which was trickey but worth doing as they were dry.



Very keen on the taper fit of the top nut in the yoke, it makes assembly easier.

New gasket for clutch cover fitted nicely. Had to help the tacho drive seal over the gasket with a Stanley knife blade. Used a smear of gasket goo to hold the gasket to the crankcase and seal the tacho drive rubber. 1.5L of oil.



Put some fuel in the carb and it leaked a bit. Shut the supply off and it kicked into life easily. Some primary drive noise and the rev counter is lazy. I'll use a digital one for the shakedown.

Swing arm pivot greased. Found the foot brake spring broken.



Very bent brake rod



Explained by brake leaver fitted upside down



Brake linings in very good condition. I have had quite a few Grimeca brakes with linings scored recently, probably due to rubbish from the road entering the open grill. Cush rubber also good but M7 x 40 retaining bolts have damaged heads. Rear wheel bearings are fine and the snail cam chain adjusters bend back into shape nicely. Rear chain 116 links 1/2 x 5/16 (428) Honda CG, Yamaha YBR etc. Sprockets have plenty of meat left.

12V electrics - 7 quid Amazon single phase full wave rectifier regulator

Will it work at all? Is it a full wave rectifier and does it regulate correctly?

Bench test -
Variac to supply 0 to 20V AC ish
Scrap 12V battery
Our regulator
A battery powered oscilloscope to look at the voltage waveform at the battery terminals (A mains powered one will be earthed and your RCD will trip)
A meter to measure the AC input voltage



At low input voltage you see rectified pulses from our alternator at 100Hz so we have full wave rectification. Mains is 50Hz and you get two pulses for each mains cycle from the rectifier. But one of the pulses is missing... So it is regulating



Turn the voltage up a bit and it misses every other pulse



I should have turned it up further to show it can turn off either side of the rectifier but I can check that on the bike which is where it counts and this test setup is connected directly to the mains which is not very safe.

New plastic switch base and rubber headlamp bush 3d printed



Our carb had been leaking which may have caused a very hard carb inlet rubber. Bob Wright had the intake rubber in stock from the NOS left by Douglas. Quite pleased I don't have to print or bodge that part because it's quite big.

Correct pivot pin for rear brake made to replace undersized thing that came with



Float bowl was still weeping a bit after replacing the float. The casting looked uneven so I ground it flat with 240 grit on a glass plate. It now sits evenly.