Forum

[Al Crusader]

Perfect lads. The voices of reason and pragmatism. After watching the video about adjusting the cams (Stinkwell courtesy of), something in my DIY bike mechanic soul flagged up a warning like a hot spark plug; do not touch this: original design, good enough; fancy after-market stuff, trouble. Lock-down too much time in shed looking for unnecessary spannering can lead to POB, ( pistonbroke ) club subscription renewal.
Following further close up inspection with my most powerful reading glasses now I knew what to look for, confirmed everything you guys have pointed out. My concern was first extracting the existing spindles, and BIG worry about inserting replacements; my history of "gently warm the casings and pop new bush/bearing/spindle in" has not ever gone according to any my wishes. Banned from the kitchen in front of hot oven. Usually the bush gets grabbed before fully in the hole, requiring horrible use of big hammer etc. I can envisage replacement spindle tight fit in crankcase warmed hole and shaving an invisible rim of aluminium into the crankcase? All very much too insomnia inducing for me thank you so much.
Anyway, not going to happen now, thanks to all your pub talk help.

[Wheaters]

I’ve seen these adjustable shafts before and wondered why. Surely the best way to minimise backlash is a good set of gears on correctly sized shafts.

[stinkwheel]

I’ve seen these adjustable shafts before and wondered why. Surely the best way to minimise backlash is a good set of gears on correctly sized shafts.

I suspect the issue is more likely the position of the holes in the crankcases that the shafts are fitted in.

[Adrian]

As far as I know the centres of cam and idler spindles are all 2" apart - with a cold engine, of course, and assuming accurate machining as per stinkwheel's comment.

As for "gently warm" the cases, you want them at about 150°C and the new steel bits replacing the old steel bits to have been in the freezer for a couple of hours.

A.