Speedo Drive Unit.

[Lobo]

..forgive me, my search failed - though I seem to remember Trig once commenting that the CB750 Speedo drive was unique in having only one part number.

Anyhoo... I want to service it. I’ve got the main central clip / worm wheel out, but now want to get the worm drive out. I’ve cautiously drilled out the brass grub screw (?) at the closed end of the worm drive, and can now see a spindle. I was expecting the end cap to free... but nope (noting that only minimal effort applied). At this point I’ve decided to pause...

So; help please.

Ta, Simon

[Trigger]

Don't try and turn the end cap. From memory it is splined. Link >>>http://www.sohc.co.uk/index.php/topic,20419.30.html

[Lobo]

Perfect - cheers Trig. I did actually try gentle taps down on the drive spindle (well it’s shaft via a weeny socket over the flat) - but to no avail. With this info - and maybe a bit of gentle heat - I’ll have another go tomorrow.

Your pic shows the end cap inverted... do I assume there’s a locating pin (for the worm drive) embedded into it?

Ta mate,
Simon

[SeanFD]

The end cap is definitely splined and, as you have found out, very tight to remove. If you can get a thin blade behind the end cap, you can work around the circumference and it will come out.

If I remember rightly, I used some heat and tapped on the spindle itself also.

[Lobo]

...thanks Sean,

This morn I admitted defeat as the cap ‘welded on’ it seems; despite heat, penetrating oil and the odd blow ... it was not for budging. It’s gone nearly 50 yrs in this state; so who am I to think it needs taking apart 😂.

So... it had a damn good clean out with petrol, isopropyl and meths - before fresh grease and a new seal put in. (oh, and a new grub screw tapped in... though why!)

Good until 2070 at the earliest 🙄 methinks...