Yet another clock resto' thread

[exvalvesetdabbler]

Not so smooth bush.

Starting to get things together for reassembly as soon as the epoxy  has had time to properly cure.

I noticed that the tacho still felt a bit lumpy when spun by hand so I flushed out the bush with white spirit.  Poured it in at the top and sucked it out at the bottom.  The first two flushes came out quite black then brown. Did 6 flushes in total and gave it a good spin each time. Then blew out residual white spirit using an air line and then put in fresh light oil using the same flushing technique.  It feels much better already.

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Regards
Dave

[exvalvesetdabbler]

Spot the difference.....

Speedo base - all 3 holes line up
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Tacho Base - mounting screw holes offset from main shaft
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I was hoping to get away with using a spare speedo base for the tacho because it was in much better condition.

Caused a bit of head scratching when the screw holes wouldn't line up

Anyhow, not making much progress,  thick zinc plate + paint = crimp band not going on easily.

Out with the sandpaper tomorrow

Regards Dave

[exvalvesetdabbler]

A bit more progress today. I had to scape some excess paint and sand down the plating a bit on the mating surfaces of the base.  This is my first attempt and practice piece using salvaged parts from one crash damaged tacho and another with good cases and seized bush(broken glass, had standing water in at some time)

Crip ring back on the best I could.  Not pretty.

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Looks better from the other side.

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Just a bit of remedial work to tidy up the scuffs on the paint and make sure water can't get in under the few wrinkles left in the crimp ring.

Lessons learned.

- clean everything and then clean again before re-assembly
- any debris inside will end up on the inside of the glass
- make sure the glass is the right way up, convex on the outside!
- too thick paint in the mating surfaces makes life difficult
- getting the ring started folding over is the hard bit
- got a big bruise on the palm of my hand now

Regards
Dave

[exvalvesetdabbler]

Question for the experts.

Why do some bases have two drain holes and some don't.  The drain holes seem to let water in rather than drain it away.

Alternative versions have no drain holes and riveted light shields.

Might these be made for different climates. For the speedo's at least, the no drain hole version was a  130 mph scale version.  The one with drain holes came from  a UK  dual mph/kph scale.
Or is one of them just an updated version.
Regards
Dave

[Oddjob]

Different makes? One a Nippon Seiki and the other a Nippon Denso? The larger ones differ in size between the 2 manufacturers and parts are not interchangeable.

I think Peter made a machine to roll the crimp ring flat, it either rotates around the clock or the clock rotates, the wheel presses the ring flat as it passed under it.

Good job BTW.

[exvalvesetdabbler]

Different makes? One a Nippon Seiki and the other a Nippon Denso?

They are all Seiki and I have had the calipers out to be 100% sure. Internals look exactly the same.  The only difference is the face plates, the fixing for the lamp shields and breather holes.  Even though the UK one has 120 mph as the largest number  and the other (US ?) has 130, when overlaid the actual values  for a given needle deflection match up.

Things like this bug me until I can find a reasoned explanation!

The UK versions came of a S Reg F2 scrap bike I bought in the mid 80S all original but totally gnarly all round. Think I paid about 90 Quid for it from a dealer that was shutting up shop and retiring. Probably never had a wash in its life either. Cylinders were on max oversize and with a washer embedded in the crown and top ring area of a piston. Bores weren't much better. Fins on the barrels are top notch though. It was probably an ex dispatch bike and had 72K on the clock. I did recover a lot of useable aluminum bits that were free of gouges or butchery  together with the yokes and a lot of bracketry, carbs/air box with all of the small bits that people usually toss when they fitted K&Ns or can't remember where they go.


Regards
Dave

[Oddjob]

The 350/400 never got the larger type clocks, I was referring to the 500 and 550 mainly. For some reason they differ in size between Seiki and Denso, I thought that maybe there were 2 makes on the 400 and that would explain it but clearly not.

[exvalvesetdabbler]

Calibration check.

Time to check the calibration before closing up the cases.

I approached this from two directions,

1). Calculate from shaft speed   Speed=60*shaft speed/2240

2). Time to clock up one mile    Speed =  3600/time in seconds

 
Assumptions,
- lathe speed is what it says it is.
- gearing of the odometer is right.


Here's the results
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We are somewhere in the region of 2.2 to 5 mph high at 42.5 mph and 2.7 to 3.6 high at 25 mph.

I will probably strap a GPS on the bike once installed just to calibrate my brain.

Screwdriver bit in the chuck and the cable lashed to the tail stock.
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Foot note:  Notice there is no difference in the colour from the main part of the face to the outer edge which would have been shielded from the sun by the inner case.  These faces are from a bike that had recorded 72K but haven't seen the light of day since the mid 80S.

Regards
Dave

[exvalvesetdabbler]

Closing up the speedometer case.

First thing to do was to fit the ring back on the upper part of the case before fitting the trip reset boot.  The boot from cb750faces have a mold line which needs to line up parallel with the case.  I just put a bit of flowable oxime based silicone on the inside to keep it in position.  Once dry I used a drill bit shank to smear some silicone grease inside the boot.

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I made a tool to get the ring starting to fold over and then used a screwdriver to press the crimp down some more each time going between each fold and folding it over further. Once at the screwdriver stage I found it easier to roll the screwdriver over the crimp while pressing down hard.  Probably went around 5-6 times.
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First time around with the screwdriver, if my pension doesn't stretch out enough, maybe I could get a job crimping Cornish pasties.!
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Finished item
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Well that's about it for this project. I set the mileage on this replacement about 100 ml more than the old one on the bike was reading and once they match up I'll swap them over.  The old speedo on the bike reads 9 mph high at 40 and has cut bands which is something I can work through without having to chuck it back together in a hurry to get the bike on the road. 

Even though I know what the calibration of the old speedo is my brain still won't let me go through a 40 speed camera at 49 and my son who has a modern bike keeps asking why I slow right down for the cameras.  I have checked it against a hand held GPS on a straight road and keeping pace with his modern bike, my brain still won't let me.

fear not , those specs of dust are on the outside after wiping off oily finger prints with a tissue and white spirit.

All the best
Dave

[Johnny4428]

Very nice job on these clocks, they are looking great and ready to put into use.

[exvalvesetdabbler]

Just when you thought it was all done,

Couldn't find the thick washers that go under the cap nuts that hold the clocks down, thought I had made some long ago but no luck, maybe they got used else where. I couldn't find anything in stainless off the shelf.  19mm od and 2.2mm thick so made some from a bit of scrap 316 stainless bar.

Drilled and hacksawed them until they were more round than square and then turned them down in the lathe using a crusty OEM washer as a guide.

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Just rubbed them over varying grades of sandpaper on a flat surface, 80 grit emery cloth, 240 grit wet'n' dry then down to 400 and 2500 grit using oil. I'll give these a polish on the buffing wheel before fitting.
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That was my Saturday evening accounted for.

Regards
Dave

[exvalvesetdabbler]

I still haven't found any M6 and M8 JIS B 1183 type 3 dome nuts in stainless has any one else come across them.  The ones usually available to DIN 1587 are a bit longer and for the picky anoraks out there they won't look right.

Thanks
Dave

[Oddjob]

Any M6 stainless domed nut should do.

I don't think there's any such thing as a JIS nut, screw yes.

I don't remember anything special about the 6mm domed nuts on the clocks myself.

I used 6 x 18mm stainless washers on my clocks IIRC. Standard thickness.

[kent400]

You can find washers in stainless but they are 17mm as opposed 19mm original and they are called spacer washers so the don't quite cover the grommet. It is essential that the correct spacer tube and correct thick washer is used to prevent compressing the cushion too much. The gauges should be flexible in their mounting plates and if compressed too much it defeats the object of cushion which is to insulate the gauges from vibration.

As for the securing nuts, they are as you found difficult find and I found some in B&Q but the were zinc plated. I re-plated them in bright zinc and that did improve their appearance.

Going back on the thread being quoted £60 to re-plate a couple of bases is way over the top. I was getting them done for a fiver each, fair to say however I had prepared them so they could go straight in the tank. The drawback was the trip there and back to get them done so now I re-plate them. Those done yesterday are shown in the image.

As for band re-fitting a tool incorporating a skate board bearing in a drill press can make a quite tidy job on the underside using the support you have for the gauge. The underside isn't too much of an issue as it can't be seen.       

[exvalvesetdabbler]

Any M6 stainless domed nut should do.

I don't think there's any such thing as a JIS nut, screw yes.

I don't remember anything special about the 6mm domed nuts on the clocks myself.

I used 6 x 18mm stainless washers on my clocks IIRC. Standard thickness.

There are 3 flavours of JIS dome nuts, it's the type 3 that we are interested in.

Type 1 threads do not extend internally past the nut portion
Type 2 undercut in the dome to allow the male thread to penetrate further
Type 3 is just a nut with a very thin dome friction welded on , allowing greater penetration of excess thread.

If you look at the M10 nut that hold the suspension on, it's a welded on cap.

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Left to right  original JIS B-1183 OEM dome nut, copy made by custom fasteners in the 80s  and DIN 1587 cap nut. note the welded on cap on the original

Regards
Dave