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Replacing Honda CB500 speedometer and tachometer face plates

10/14/2009 3:02:13 PM

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CB500 Speedo and tach, done
The finished gauges on the BikeBandit.com/Motorcycle Classics Project Cafe, complete with custom face plates. Pretty cool, eh? 

If you’re old Honda has spent any time in the sun, it’s a pretty good bet the speedometer and tachometer face plates are cracked and faded. Thirty-some odd years out in the elements will do that to a bike. The good news is, you can make those face plates look like new – or give them a personalized look – and it’s not as hard as you think.

CB500 gauges, before rebuild
Here's what we started with. Pretty typical, really, and pretty ugly, really. 

As part of our BikeBandit.com/Motorcycle Classics Project Café, the 1973 Honda CB500 Four we’ve slowly transformed from a tired dog, ready for the parts bin or the junk yard, into a gleaming, lovely little café for the street, we decided to freshen up the bike’s clocks. We’d never tried disassembling a set of Honda gauges, so we went into this as cold as the next guy. And while it definitely takes a little time and patience, we discovered it’s a project completely in reach of the average guy.

Unfortunately for us, the telling of this tale got let down by technology, or maybe just bad “best practices,” you decide. I documented the entire process, taking pictures of the speedo and tach from start to finish as we worked through, but an unexpected and pretty devastating system failure in my computer resulted in losing just about every pic I took. A few – the ones you see here –survived, but that’s all. Had I backed everything up to a disc, I’d still have all my pics. There’s the “best practices” element. Fortunately, someone else has already documented the job.

It was, in fact, because of Steve Swan’s excellent step-by-step instructions for disassembling/assembling CB750 gauges on the SOHC Honda CB Motorcycles website that we decided we were up to the task. The process is nicely documented on the SOHC tech pages, and we relied heavily on the SOHC article to get our gauges apart.

As excellent as that article is, there are some differences between the CB750 gauges and those used on our CB500. Thanks to our paucity of pics, it won’t be very instructional to try a comprehensive walk-through – you can get that on the SOHC page. Instead, I’ll point out some of the things we learned that differ from the SOHC article and some of the elements unique to the CB500 gauges. If you’re going to follow along, you might want to print this out so you can refer to it while going through the SOHC article, or put both articles up on different pages in your browser and flip back and forth.

Step One: Removing the crimp bandOnce you’ve removed your gauges from the bike, it’s immediately obvious that the biggest challenge in getting to the face plates is splitting the gauge body, which requires removing the crimp band holding the upper and lower parts of the gauge case together. The SOHC article suggests using a utility knife to uncrimp the band, slipping the blade up under the crimp band working from the lower side of the band (gauge face facing you), then using the knife blade like a miniature pry bar. We found it was much easier – and safer – to use a very small screwdriver, gently prying the band up and with a little sideways twist. As the SOHC article shows, once you get the crimp band to start bending back, move in baby steps around the entire circumference of the gauge, slowly prying the band open. We ended up working our way around the gauge about four times, transitioning to a slightly larger screwdriver in the process, lifting the band a little farther with each pass until it opened up enough to slip off the gauge body so we could separate the two halves.

CB500 speedo, prying off crimp band
Use a screwdriver to gently pry the crimp band off, twisting up and a little sideways. We started with a small screwdriver and then transitioned to a slightly larger one, once we'd made our first pass around the band. 

CB500 speedo, crimp band loose
Here's what the crimp band should look like once it has been completely opened up. It takes a bit of work to get to this point, easily 15 minutes, so be patient. 

Step Two: Removing the trip odometer reset knobTo remove the inner speedometer assembly from the gauge case, you first have to remove the trip OD reset knob. Unlike the CB750 speedometer, where the trip reset knob screws off its stem, the trip reset knob on the CB500 is held onto its stem by a very small Phillips head machine screw. In our case it was rusted in place, and wouldn’t screw out. To remove it, we took a small drill bit just slightly smaller than the head of the screw. Drilling carefully and gently, we drilled through the screw head to the body of the screw. The tapered profile of the drill bit lets you remove most of the screw head until the bit hits the screw stem, at which point the head should pop off. The knob then slips off, and we removed the rest of the screw with a small pair of locking pliers. The threads in the shaft were fine, leaving us only to find a small, metric machine screw to hold it together on reassembly.

Step Three: Removing the face plateThe SOHC article doesn’t address removing the face plate (it focuses on repairing a bad gear), so we called up Honda CB750 guru and café fanatic Steve “Carpy” Carpenter at CB750cafe.com for advice. The big issue was how to remove the speedo and tach needles without breaking them. Carpy told us they’re just a press fit on the shaft and come off easily, but who wants to break one once you’re this far along? Essentially, you need to lift the needle straight up and off the shaft, but using what? Carpy uses a pair of pliers, but we discovered the perfect tool; a common dinner fork. Using one of the two screws that hold the face plate on as a fulcrum, we inserted a regular bladed fork under the center of the needle, rested the butt of the fork blade (the part below the fork tines but before the handle) on the head of the screw and then gently pried down on the fork handle. The rocking action provided by the arc of the fork lifted the needle off perfectly! I think I need to patent that one. Once the needle’s off, it’s a simple matter of removing the two Phillips head screws holding the face plate on and that’s it, it’s off.

Step Four: Replacing the face plateOnce the face plate’s off you have a couple of options. The first of course is to replace them straight out with standard faces. Charlie O’Hanlon at Charlie’s Place in San Francisco works with a fellow who does perfect Honda replica faces, which is great to know. Okay, cool enough, but since our bike was/is a non-stock café special, we decided to do something a little different, so we turned to Carpy. Carpy’s been in the Honda café scene about as long as anyone, so we weren’t surprised to discover that he’s created his own custom face plate transfers. Carpy will sell you the transfers straight out, but we opted to send our face plates to him. Using our specs he made up a custom set of transfers, cleaned our old face plates and applied the new faces. We got them back in about a week, and the results speak for themselves. They look fantastic and really help finish off our café theme. Carpy can supply just about any design you can think of, and Carpy also has step-by-step instructions for replacing the face plates on CB750 clocks on his site. The only place we differ with him is on removing the crimp band, which he cuts off – it’s not necessary, and then you have to fit a new band or, as Carpy does, glue the old band back together.

Step Five: Putting the gauges back togetherWe cleaned our gauges thoroughly inside and out before putting them back together. They’re not hermetically sealed, so you don’t have to be too anal about it. Get them clean, and make sure the rubber seal on the upper half is still in good shape, maybe conditioning it a bit with some WD40 so it will go back in shape. With the gauge in place, place the two halves together, followed by the crimp band. Drop it in place going from the upper half to the lower, with the end you pried open facing the lower halve of the case. You’ll have to gently push it in place. Before going any farther, make sure the case halves are properly oriented to each other so the gauge face will be straight once you mount the speedo or tach back on your bike. Now, take a set of duck-billed pliers and a soft rag. Place the rag between the pliers and the outer face of the ring (the part you didn’t pry up – it has a nice chrome finish on it, and you really don’t want to mar it), and gently squeeze the crimp band down, putting the pressure on the side you opened up and gently rolling the pliers forward to seat the band. Do this slowly and carefully and the band will crimp in place without damaging the exposed side. Just like removing it, we worked our way around the gauge a few times to get it crimped back evenly.

CB500 speedo, re-crimping
Re-crimping the band takes the same kind of patience as removing it. Work your way around slowly with a pair of duck-billed pliers and a rag protecting the finished edge, gently re-crimping the band while gently rolling the pliers up to help seat the band and lock the two halves of the gauge together. 

CB500 speedo, done
Here's a close up of our finished speedo. Cool. 

Step Six: You’re done!That’s pretty much it. Bolt those suckers back in the handlebar mounts and you’re in business. You might have noticed that our upper gauge bodies are polished. Near as we can tell, they’re made out of stainless steel. We started sanding off the damaged paint to repaint them, but once we saw how easily they’d shine up, we figured to hell with paint and just polished them up on a polishing wheel. They look great, and it’s loads easier than painting them. If we’ve left anything out, please add to our experience by using the “Comments” feature and fill us in on what you know. – Richard Backus 

 

CB500 Speedo and tach polished
A better view of our polished speedometer and tachometer. Since our bike's non-stock we didn't have to worry about paint, and frankly, we think the polished gauges look better than paint.


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Post a comment below.

 

caffeineandpixels
6/8/2010 11:06:41 AM
If you go to flickr and search under caffeineandpixels you can see some gauges I designed for CB750's. You can also go to MilVinMoto and look at Godffery's Garage for some incredible restorations of CB's of all sorts.

Suzsmokeyallan_2
3/21/2010 8:39:28 PM
Restoring gauges is an art form that covers all aspects of their inner workings, especially the proper way to open and reseal the bands so they do not leak. I do not use and dont subscribe to using pliers of any sort to reseal gauges opened for restoration. Doing this will not create a correct and even pressure onto the rubber seal thats sandwiched inside the ring/bezel joint, and you risk the possibility of marking the bands upper visible surface with impressions as well. While the factory did use a two stage roller principal to fold the band and correctly pressure crimp it, a similar process can be used without making such an elaborate tool as the factory one. I do restoration work on mostly GT750 gauges but HTMLs are not allowed to be posted here so do a google search for gaugerestore to see my site and restoration work.

pumps
10/15/2009 3:54:32 PM
Great how to. I have a 1977 Yamaha XS650 that I recently rode to a local rally. I had done a front end rebuild and only two problems on the trip. The cable came out of the back of the speedo( I must have forgotten to tighten the new one when I installed it) and on the way home the screws vibrated out of the already loose gauge face letting it spin about 90 degrees. I was able to uncrimp the bezel as you have described. Cleaned the gauge face and glass. put some loctite on the screws and re-assembled successfully. So you know where to get Honda replacements...how about replacements for faded XS650 clocks?

todd
10/15/2009 2:23:55 PM
So what's the trick for getting the needles back into the correct position? I did this on my R75/5 but I wasn't able to determine how much pre-load was on the speedometer needle's spring. First it would show an incorrect speed but now the needle has loosened up and rotated on the shaft so that 80 mph = 0 mph. When I'm on the highway I'm now running at around 160 mph. Pretty good for an old BMW. can't wait to see the final results of the Project Cafe. -todd

Bill Corbin_1
10/15/2009 10:58:10 AM
I really appreciate your uncovering this restoration secret. Honda gauges, as well as most others, were not built with any UV protection, so most vintage bikes, if out in the sun much at all, have faded gauge faces. I have a nearly pristine '76 Goldwing LTD, that I purchased with only 8,900 on the dial. It has absolutely no evidence of weathering, except of course faded gauges, especially the redline indicator. I found a NOS damaged tach, and have been wanting to open both tachs to switch face plates to return my LTD closer to concourse. I've thought about that crimped band for some time and have been very hesitant to tackle working at it, but your article has provided me confidence to "just do it." Your well documented procedure, back-up references, and great pictures, is exactly what I needed to move ahead. Thanks...keep on with your great work, supporting those of us who idolize the vintage bike. I have 2 early Goldwings and can't imagine buying a new, hughly expensive cruiser/tourer due to my bulletproof, smooth running, fast handling Wing. Feel free to research and write on one of the most amazing motorcycles ever designed...the Honda GL. I look forward to each issue and only wish you'd build up to publish monthly. I'd pay double + for this. Regards, Bill

cballweg
10/15/2009 10:12:23 AM
Just another example of how you seem to understand how to bring extra value to those of us who love the old bikes. Thanks.



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