Fork Oil Change

Mart UK said:

Don't follow. The weight of the bike is on the forks when I stand it up, off the sidestand, too?

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What I meant was that when the bike is leaning on the side stand the forks often remain slightly compressed.

Mart UK said:

Bike sitting on sidestand, I lift it upright. Fine. When I turn the bars to straight, the front rises up a little on the forks, before I put any of my weight on the bike.

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Possibly has something to do with the steering geometry why the forks extend slightly when they are returned to the straight-ahead position.

Mart UK said:

If I bounce it up and down with the brake on, the fork movement is smooth and nicely damped, regardless of the direction of the bars.

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Then I don't think there is anything to worry about as there's going to be some stiction in these ancient forks.

Oil specifically marketed for forks has an additive package with very little in common with additives found in engine oil; fork oil is more like hydraulic oil. Back in the day fork specific oil, short of ATF was rare to non-existent. Engine oil was recommended, for the most part; Triumph, IIRC, was the first Brit bike that specified ATF.

Oil specifically designed for forks is now quite common, I recommend you use these over engine oil.

Best.

In the end I upgraded with the JRB kit with all new internals and stantions and 150cc of 10W belray fork oil , nice front end from then on , also rarely left bike on side stand as it was mostly a Sunday ride only and bike lived on centre stand …