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Resetting Guage Cluster

8923 Views 32 Replies 15 Participants Last post by  Drahcir


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Tried that a few years back on the CB350. But since my old Home Utility (pre Black & Decker) hand drill only turns about 700 rpm, it read 15 mph on the speedo.

After about half a day I gave up. Put 100 more miles on the CB without even trying.

Maybe use a Moto-Tool?
Re: Why do it the hard way?

Wow, and maybe after you're done with the speedo, it'll be 1976 again. Time travel problem solved. Should report this to NASA.
The 3 lb sledge is the "fine adjustment" tool.

I would upgrade to the ten pounder. better handling, more power, the usual stuff we bikers crave........... :+)
You are most likely right about the pulse generator, but, I believe that the speedometer cables run through a gear reduction so that there is less than one revolution of the cable per wheel revolution. VWW
Re: Why do it the hard way?

I gave some thought to reversing the direction, but I wasn't sure that the cable didn't turn a worm gear. Now that I think about it though you couldn't roll the bike backwards too far without damaging the gears in the odometer if that was the case. VWW
Now that's a little much in my book. Here's a short breakdown:

1/2 lb. Ball Peen: Carbs, lighting.

3/4 lb. Ball Peen: Shifters, brake levers.

1&1/2 lb. "small"Sledge: Exhaust Systems.

2 Lb. Sledge & up: Frames, forks. Rims. Quick

removal of fooforaw.

I usually reserve the 10 pounder for my 5 hp

Fairanks Morse hit-or-miss when I recalibrate the mains. Also for slaughtering cattle.

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Yes, there usually is some gearing - I've no idea whether it's usually a reduction or not. I was just ignoring the possibility to simplifying the calculation for illustration purposes.

It's worth pointing out that even if it is reduced a lot,, you can't just run the speedo at a thousand miles an hour to rack up the odometer miles more quickly, because the old fashioned speedometer is likely to explode messily under the strain.
You make an interesting point, however isn't a speedometer operated by a spinning set of magnets working against a spring preload? If so when the speedo pegs the needle that will be the maximum that the spring is streched, so the only added difference in strain between say 180 mph, and 1000 mph would be the added load on the barings and the gear teeth of the speedometer. VWW
They never did figure it out. I had the stock screen the first time it happened, then a double bubble smoke. It always melted in the same spot adjacent to the 7 at around 3-4k miles. They replaced it 3 times and had plans to try something else when I low sided on some gravel it and the bike was totaled. The dealer was always really cool about it and had called a rep from Honda to see what they could do for me, but they dropped it after I crashed. I really was amazed at how well they treated me at the dealer and never gave me any hassles at all. I wonder what would have come of it if I hadn't crashed?
That is a free pass to the gray bar hotel!
I was thinking that the rotating components of the average built-down-to-a-price motorcycle speedo are unlikely to have been dynamically balanced for high-RPM rotation nor equipped with a suitable bearing if they are designed to rotate slowly, and just the vibration of running continuously for 4 days and nights at 1000mph may cause things to self destruct, never mind the heat. I'm also thinking that if you run the speedo drive 8 times faster than it was ever designed to run, you are generating roughly 8 times the magnetic field and thus 8 times the current in the field coils and 8 times the turning moment on the pointer. Since the only thing stopping the pointer from spinning like a desk fan and winding the hair-spring up to destruction is usually a little end stop right down near the end of that long, thin, lightweight metal or plastic pointer, and the only thing stopping the central shaft spinning and leaving the pointer to drop off if that stop holds is usually a little detent or flat on the end of that tiny shaft, I wouldn't want to bet real money that the speedo would ever play the piano again after subjecting it to the 1000mph rewind experience.

The only way to know for sure would be for a MOron with time on his or her hands and a spare speedometer to rig something up and do an experiment for us, then write up the results.

In fact, that's just the kind of quality motorcuycle-related article I pay my subscription for. Get right on it, MO!
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...then the weight of the average un-laden sparrow is considered against the weight of the average coconut...


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