Topic: CB550 Speedo Drive Gear Help..!

[stevo]

Hi,

Another newbie here... so thanks in advance. I've tried looking through the archives, but can't find a specific answer, hopefully easy to someone's with a bit more experience than me - which shouldn't be hard

I've a '78 CB550 and I've some Speedo Woe's. ie it doesn't work.

I unplugged the cable at the front wheel end, popped a drill on it and the speedo read - so it's not a cable or speedo issue.

I then raised the front wheel and spun it and the tooth in the gearbox drive spun - however if I stuck my finger in there to give it some resistance it stopped spinning.

So I took the speedo drive off and everything looks in pretty good nick. Also when I firmly clamped the two parts of the drive together it span the outter tooth and didn't stop with a little resistance from my finger this time.

It's at this point I am confused... as everything seems OK - what I'm also confused about is how the back of the speedo drive connects to the outer casing of the wheel bearing - am I missing an O-ring here or something? It seems to me as when it's clamped together via the spindle the wheel will turn, the outer part of the speedo drive will stay still, but there is nothing to make the speedo drive with the teeth actually turn - or is clamping it enough force to drive this? Either way something isn't right or working...

Have attached some pics to show what I have!

Help / advice much appreciated!

Steve

1978 CB550K

[stevo]

I've been doing some more digging and my bike has had a dual disc conversion. I think the previous owner has ground the drive plate down as it's missing it's 'ears' - hence it won't spin with the wheel - and hence the speedo doesn't work. Any ideas how I could attach it somehow - or do I need to weld new 'ears' on?!!

Thanks

[DaveBarbier]

That speedo drive plate needs to be pinned in place on the hub. See my pictures attached. It shouldn't just come out like that. This was taken before I hammered the pins in obviously.

[stevo]

Thanks Dave - that makes sense - at least I'm clear on why it's not working.

Now excuse my absolute lack of knowledge, but have you then simply drilled 2 holes in the drive plate and straight through into what I suppose is the hub? What kind of pins are these and what stops them coming out? Sorry for all the questions!

Thanks

[DaveBarbier]

No problem, you'll need to drill holes in the drive plate then set it on the hub inside the rotor carriage, mark where the holes are and drill. Use split pins (aka spring pins) and tap them in. Just friction holds them in place. You drill a little smaller hole so it squeezes in. Doesn't need loctite or any adhesive.

The orientation also doesn't matter but it's a little bit of a pain to make sure the speedo slides on and engages properly.

Hope that helps!

[stevo]

Thanks for the advice David - that seems do-able!! Famous last words....