o-ring (or other) replacement for 74-75 speedo damper?

DogBunny

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4cf280e4cccca8cad1c5e99dc2f60867f508f680.png

I am trying to find a workable replacement for parts 7 and 14 in the diagram. These rubber dampers are absolutely unobtainable new or used, but are critical to keeping the gauges secure.
My thought is that there must be an off-the-shelf o-ring out there that would substitute. Maybe 3 or 4 stacked o-rings.
Capture.PNG

Maybe a square or quad ring.
My problem is that I don't know what size to look for. Does anyone by any chance have an original damper that they can measure, or know what the size is? Or does anyone have another solution? Doubtless there have been other threads on this subject, but I couldn't find them. Thanks.
 

5twins

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I'm dealing with this on some later gauges. If the earlier ones are similar then the ring appears to be more of a foam rubber than actual o-ring type solid rubber. Maybe some rings stamped out of dense thick foam rubber sheet?
 

DogBunny

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What later gauges are you working on-- I assume non-XS650...
I completely agree that foam rubber is more correct than o-ring type solid rubber. And I also thought of cutting dampers out of a foam rubber sheet. However there are a couple of problems -- first, where to get the appropriate foam rubber sheet at a reasonable price. And second, how to cut-out such a thin-walled damper from the sheet. Stamping it out rather than cutting would be ideal, but who can stamp such a relatively large diameter?
So that's why I still like the o-ring or square-ring idea. From the diagram, the length of the original damper is considerable, so I think you could just keep stacking rings until the whole gauge-and-bucket assembly tightens securely.
I imagine that others have used sheets of air filter foam, cut and rolled into a cylinder and the butted ends glued together with rubber or contact cement.
 

bluesman650

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HI, I just went out to the barn and checked a set of gages I had sitting around. It looks to be about 31/2" id. 1/4" thick and about 5/8" deep. It almost looks like type of tarry packing like you would use on roofing or something. Mine is all dried and hard. I'm wondering if you couldn't maybe form something up using black rtv and a piece of 3 1/2" pvc
 

DogBunny

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bluesman650, thanks for those measurements. Yes, those dampers often become tarry and/or brittle, but I'm pretty sure they start as foam rubber.

5twins, I hear you on the price for the 77 and after dampers. This is one of the few exceptions where I'll pay the crazy price. I have bought many of those dampers from Partzilla. Once you get past the price, they are a real pleasure to use. They go on easy, fit perfectly, and completely eliminate meter slop. As xjwmx recently opined, meter slop may contribute to breaking needles.
 
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DogBunny

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xjwmx, that's a good idea. However, I think I have hit upon a very elegant solution. First, a closer look at what we are dealing with:

DSC02795.jpg

On the right is the tach, with typical crusty, melted-on old damper.
On the left is the speedo, after the old damper is scraped off. The rubber bezel "bumper" peels off. Note the circled raised nub.

DSC02798.jpg

The speedo again, this time with the gauge bucket slid all the way down on its mounts. The gap that the damper needs to fill is 16mm, but you want to make the damper slightly longer so that you get some squish -- this is what will hold the gauge securely in place. Also note the taper that occurs right where the damper will go, and also the "nub," both of which will have to be dealt with.

DSC02799.jpg

There is a raised rib on the dash bracket, which also occurs right where the damper goes and that will also have to be dealt with.

018578002647.jpg
So, I found this at Lowe's:
https://www.lowes.com/pd/Fernco-3-in-x-3-43-in-dia-Flexible-PVC-Coupling-Fittings/1000075353

018578000773.jpg
Also found this:
https://www.lowes.com/pd/Fernco-3-in-x-3-38-in-dia-Flexible-PVC-Coupling-Fittings/1000075375
Pretty much the same thing as the first one, but the thickness of the rubber is different. I bought one of each, tossed the metal hose clamp parts, and lo and behold, the rubber sleeves are pretty much a perfect slide fit on the gauges.
Stay tuned...
 

TwoManyXS1Bs

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...maybe some house door weatherstripping. Adhesive on one side, seen it advertised as closed cell foam, so might be durable..

Ditto. Also RV and truck/camper weatherstripping, 2" wide strips. Used that kinda stuff before with success. Could Google "automotive weatherstripping profiles", adhesive backed strips like these JC Whitney offerings.

WeatherstripProfiles01.jpg WeatherstripProfiles02.jpg

A long shot, but I recall seeing some instrument ring dampers in some of the links in this post. Check the other posts too.

http://www.xs650.com/threads/rubber-restoration.48125/page-2#post-551459

More here:

http://www.xs650.com/threads/rubber-surrounds-for-guages.34573/
 

DogBunny

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TwoMany, thank you for those links. I knew there had to be some threads on this. However, the rubbers from those Lowe's flexible PVC couplings looked really promising to me, so I continued down that route:

DSC02801.jpg

Here's the rubber from this one:
https://www.lowes.com/pd/Fernco-3-in-x-3-38-in-dia-Flexible-PVC-Coupling-Fittings/1000075375
The rubber on the other one is too thick, and will be going back to Lowe's.
I wrapped a strip of 18mm masking tape around it as a cutting guide.

DSC02802.jpg

I put the rubber sleeve on the gauge for support, and cut my damper piece from the sleeve. The 18mm damper fills a 16mm gap, so there will be 2mm of "squish." It turned out to not quite work out that way, but I still like making the damper 18mm wide.

DSC02799.jpg

So, I gave this very simple damper version a try, but assembly got hung up by the raised inner rib in the dash bracket.

DSC02803.jpg

I decided to try splitting the damper in two, with one piece above, and one piece below the raised dash bracket rib. I turned version one of the damper inside out and slid it back on the gauge for support. There are raised rings on the rubber sleeve -- I used one as a guide for splitting my damper.

DSC02804.jpg

Here is my finished damper. One piece is 6mm wide, the other is 12mm.

DSC02805.jpg

And here is the assembled gauge.

DSC02806.jpg

Does it "dampen" exactly like the original? Probably not. But it does look great, and there is zero meter slop. The Lowe's flexible PVC coupling cost $4.86, and one coupling is enough to do both gauges.
 

DogBunny

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Thanks Skull.
I recently acquired a handful of 1974-75 gauges and brackets. I noticed different variations, and I tried to sort them out so that they would make sense to me in the future. Beginning with the speedometers, here is what I came up with. Confirmation and or dissent is welcome.

DSC02821.jpg

1974: 447-83570-40-00
1975: 371-83570-43-00
I'm not 100% sure on the finish of the bezels -- I think some left-over 1974 chrome bezels may have been put on 1975 speedos.

DSC02815.jpg

1975 has collars to compensate for the shallower depth of the meter.

DSC02816.jpg

The different positions of the trip meter reset knobs means that the "cups" or "buckets" that surround the meters are different -- I'll get to that in a bit...

DSC02818.jpg

The best parts diagram that I could find for 1975 meters is the old biker.net version. It calls for only one collar which is clearly wrong -- the 75 speedo should have two, same for the tach, for a total of four collars.
 
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DogBunny

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Speedometer cups:

DSC02822.jpg

1974: 371-83507-70-00
1975: 371-83570-72-00

DSC02824.jpg

Here's a 1974 cup that a previous owner modified to accept a 1975 speedo gauge showing the differing trip meter reset knob positions.

s-l1600a.jpg

To further muddle things, Yamaha offered the chrome cup with a different part number, 371-83507-09-00. This is a NOS one on eBay.

s-l1600.jpg

And here is another NOS eBay chrome cup holder with the same part number, but the trip meter reset knob is in the alternate position...
 

DogBunny

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Tachometers:

DSC02826.jpg

1974: 447-83540-40-00
1975: 447-83540-02-00
As with the speedos, I'm not 100% sure on the finish of the bezels -- I think some left-over 1974 chrome bezels may have been put on 1975 tachs.

DSC02827.jpg

Depth and mounting stud differences are similar to the speedometer.
 

DogBunny

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Tachometer cups:

DSC02825.jpg

1974: 371-83508-70-00
1975: 371-83508-71-00
The 1973-1975 RD250 and RD350 use similar gauges, but nothing will cleanly interchange. The tachometer cup will fit, but the diameter is different and a custom damper will have to be made -- neither the XS650 nor RD250/350 damper will fit. It looks like the RD250/350 speedometer cup will only fit the 1974 TX650 speedo cup due to the trip reset knob position.
 

650Skull

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Well diagnosed DB. I have done a bit on these when Mike, (Aus) was trying to repair his 75B gauge trip meter. I agree with every thing you have found.

Yamaha made it hard for them selves on the 74 Speedometer when they changed the trip nob from the side of the gauge to the rear. Seems they left the Odometer dial on the top of the Gauge face and the tip meter on the bottom, (same as 70-73), and due to the placement at the rear of the gauge of the trip nob, (due to easy access i presume), they had to make up a conglomeration of gears to access the trip meter.

On the 75 they changed the Odometer and Trip meter around, (Trip meter on top and Odometer on the bottom of the face plate), so the trip nob shaft was a direct drive to the Trip meter.

In 76 they changed the trip meter knob back to the side of the speedo and also changed back to the Odometer on top of the gauge face and trip meter on the bottom. 75 is a one year only gauge face plate.

TX74A...................................XS75B
74-75 early IMG_7270 2 text.jpg 74-75 later type speedo 6.jpg
 

DogBunny

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Skull, good story, it explains a lot. Yamaha and Nippon Seiki sure went to a lot of trouble for gauges that only lasted a couple of years.

This is mostly speculative, but I think that all of this fussing around with the gauges actually dates back to the 1973 RD350. 1973 was the first year that Yamaha used the cast aluminum "figure 8" gauge and dash bracket (yes, it is cast aluminum with black paint). In 73 it was used on the RD250, RD350, and TX500. A similar but more complicated Figure 8 was used on the 1973 TX750.
1973 was the first year for the RD350 which is a direct descendant of the 1972 R5. I think they took the R5 gauge, moved the reset knob from the side to the back, and put it on the RD350 and also the RD250. They made a slightly larger diameter gauge for their new 1973 TX500 that used the same Figure 8. I think they would have put the Figure 8 on the 1973 TX650, except they were already in the process of completely re-doing the frame and forks, so they decided to wait a year until the new frame was ready.

The 1973-74 RD250, RD350, and TX500 all have the complicated trip reset knob linkage, just as the 1974 TX650 does. In 1975 they fixed it on all models and swapped the odometer and trip meter positions.
The 73-74 TX750 was discontinued before they could simplify the reset knob linkage on it.
 

Okie

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Thanks for all your hard work documenting this. I have both 74 & 75 gauges Im re-doing. On the 74 I used a TX 500 bracket since Im just refurbishing, repainted and re-labeled the face since the the 500 had an oil light where brake lining light goes. The 75 Im trying to get original, & this is valuable info! Do you know a source for the small screws that hold the bulb holders in?
 
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