Restoration Yamaha LS3 1972: Fixing the front fork

When I took the front fork legs apart there wasn't much oil in them anymore. One of the inner tubes was in good (pit-less) condition but the other one was pitted badly.

Yamaha LS3 rusty front fork

Pitted inner tube front fork Yamaha

I asked around but there wasn't anybody who could repair it. Luckily the inner tubes of the Yamaha LS3 aren't visible so I decided to fill the pitted parts with JB Weld. It's very strong, smooth and chemical (oil) resistant. If you don't fix the pitted surface your new oil seal will be gone within a couple of days...

Fixing inner tube front fork with JB Weld

It took a while before it was really cured, so I sanded it after a week up to grid 1500.
Another issue which had to be be solved were the old leaky fork seals. They're sitting inside the so called "outer nuts". With a home made tool I took the old ones out, see http://yamaha-ls3.blogspot.com.au/2015/04/removing-front-fork-seals.html Inside the outer nut is also an O-ring hidden in a groove. Don't forget to replace them as well.

One of the outer nuts was too damaged to fix so I bought a new one at www.cmsnl.com . The new fork seal is already fitted in the outer nut, but the O-ring isn't, so make sure you put one in. The rest of the old chrome work was stripped back, sanded and DIY nickel plated.

When I wanted to put all the parts back together the inner tube top bolts both got jammed, but a M10-1.25 tap cleaned the threads out and with some copper grease it was all good.

Cleaning inner fork tube thread with M10 - 1.25 tap

Cleaning "harvest" after chasing the threads

With a longer bolt I pulled the inner tubes all the way up in the triple tree and tightened the securing bolts. Make sure they are both all the way up otherwise you'll get weird things..