Clock decal overhaul

[simonster]

I'm in the process of restoring the clocks on my 72 500 k1. I've opened the speedo by uncrimping the band and have ordered new decals. But I've got to the stage of removing the needle and have read two ways of safe removal, one being to prize the needle vertically off the shaft or the other to rotate the pin anti-clockwise beyond the 0 position. Has anyone tried either technique with any success?

[Lobo]

Until Kent400 (Peter) steps in... the forum guru on clock renovations...

I've done 4 clocks, with complete success by using the 2 teaspoons under the needle boss method. Simply put them opposite each other, as close to the spindle as you can get, and gently lever the needle up symmetrically. It'll come off with a ping... ie don't do this near open drains / a nice roaring fire what-have-you.

Don't at all like the sound of rotating the pin beyond the 0 position, sounds fraught for bending it!

Simon.

[UK Pete]

I have used a fork with good success in the past,
pete

[paul G]

Two spoons work a treat but as lobo states whatch where it goes I spent 15mins grovelling under my bench trying to find one

[Trigger]

Two spoons work a treat but as lobo states whatch where it goes I spent 15mins grovelling under my bench trying to find one

Did one years ago Paul in the kitchen. Thought it would be the safest place to find the needle again. Wrong, it hit the ceiling and as far as i know went down behind one of the wall mounted cupboards. 16 years on i still have not found it.
when using a teaspoon or any other method, put a towel over the clock. 

[kent400]

Yes two teaspoons is the best method, position them so the underside of the spoons are resting on the dial face screws and provide the same pressure on both sides to avoid bending the needle pin.

Hope you put a large hose clip or clamp around the band before you lifted the edge of the base otherwise the band can be distorted and a blighter in the to re-crimp.

Good luck with them

[simonster]

Cheers for all the advice. The two spoon method worked a treat. No I didn't use a clamp around the band, kent400. I just took it real steady with ascending sized flat drivers and was pretty pleased with the result. I can see how the clamp would make it less likely to damage the band and clock cone and will use that method on the rev counter and post the end results.

[simonster]

Also, I used cling film over the face when I popped the needle. Same idea I know , but being the novice, made it easier to see what I was doing.

[kent400]

Oh, cling film over the needle sounds quite a good suggestion. I just use a duster but I suspect needles have ended up in some interesting places, cat litter tray anyone?

Using a hose clip around the band before removal prevents the band bending outwards as it's removed, there's only about 3mm of the band folded over the base. If the band is bent outwards you end up with even less to fold back over the base.

On the larger CB750f type there's even less of the band folded over the base so even more essential to clamp the band before removal. Also a good method to use on those gauges were a bezel holds the glass. Bit more of a problem if the gauge isn't round, square ones are tricky but a hose clip can still be tightened and will more or less take the shape of the bezel.

[Lobo]

Hi Peter..

Whilst you're here (!) can you perhaps pen a few words on how to fill / top up the damper pots in these instruments? My 750 speedo fluctuates +/- 5mph .... assume not normal, even for 1972.

Cheers,
Simon.

[AshimotoK0]

Hi Peter..

Whilst you're here (!) can you perhaps pen a few words on how to fill / top up the damper pots in these instruments? My 750 speedo fluctuates +/- 5mph .... assume not normal, even for 1972.

Cheers,
Simon.

Yes I would like to hear from Peter too on this but I have asked before here on the USA site:

http://forums.sohc4.net/index.php?topic=78890.0

Lecram has a video of before and after but don't think specifics of how to do it.

I have a litre of silicone oil but need to get it's viscosity measured.

Cheers ...Ash

[simonster]

Having just opened the tacho and found it in worse internal condition to the speedo. With some metal decay around the inner base. The working mechanism has discolouration on the load spring ( don't know the correct term ) and turning the needle manually does cause it to unload back to its original position most of the time... However it occasionally sticks and I can feel some resistance on  the needle shaft. Is this serviceable? Can I lubricate? I know there is some mention of using silicone oil in this thread but no definitive answer. Will spray quick dry solvent help in the first instance to clean up before lube. Cheers


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[kent400]

The chances are that some rust flakes for the inside of the base have been attracted to the internal magnet that's connected to the drive and are jamming the aluminum magnet cover. If that's the case you might be able to remove two tiny screws on each side of the frame and lift off a small aluminum shield to gain some access to the magnet. Beyond that you have to grind off the barbs that secure the front of the frame to the remainder. It then possible to remove the magnet cover but this is a tricky business, especially re-fitting.

As for the dampers, differant types on the smaller gauges the front of the gauge has to come off and the silicone grease replaced. Again a tricky business. Several differant types of dampers one the larger gauges, one you can remove the end cap to refill, great care required. The other type a hole is drilled in the damper to refill. A wavering needle isn't always due to lack of damper fluid, the drive cable can be the cause. A easy test for damping is spin the drive end, if the needle drops instantly to zero there no damping effect. The damping effect does vary a bit in so far how quickly the needle drops to zero but it should not drop instantly when the drive ceases. Hope that helps

[kent400]

On forgot to mention if the tacho mechanism is beyond repair I may well have one in the spares box.

[simonster]

Thanks for that advice. There is definite damping on the needle because when it does return there is that nice millisecond delay before smoothly unloads to zero. This is how it looks if you could advise on the type of mechanism I have. Cheers



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