Noisy Speedo, over and over and over again.

This is now the second speedo for my 82 xs400rj and the 5th time I have taken it apart to remedy the loud whirring sound that so many other have spoken of on these forums. I have read and followed bigfitz52's guide on cleaning.

Each time, I open it up and lubricate the long whitish gear at the bottom of the housing, the one that makes contact with the central metal shaft. I have tried silicon, lithium, wheel bearing grease, and chain oil. I have also had the Cable replaced. The gears themselves appear to be in good condition.

The sound will go away for a few days, then come back louder than before. I keep my bike in a garage.

Any suggestions, or should I just sink the money into an electronic dash? At this point I'm ready to say that the OEM plastic gears are simply wearing out from age. My first speedo died completely from this same problem.

 

OK, but it sounds like you're not fully lubricating the input bushing.

Here's my article: http://xjbikes.com/Forums/viewtopic/t=15303.html Count down the pics; it sounds like you're lubricating as shown in pic 9, but not getting the bushing from the outside as in the 10th pic. You need to get lubricant between the inner piece that rotates and the housing; the hole where the cable goes is blind no need to shoot lube in there.

Also: "Had" the cable replaced? As in, somebody did it for you? Did the new cable get properly lubricated in the process? (New cables need to be lubed too.)

One other question: that bike has a mechanical tach too. Are you 100% sure it's the speedo?

 

So I have tried lubricating the bushing as well, but I have been able to pin-point the noise to the long white gear (the "worm" gear in your third pic) which makes contact with the "input head". I take the speedo off, hook it up to the speedo cable, and spin the cable with a cordless power drill. It is definitely coming from the speedo, and seems to be coming from the worm gear, not the input shaft. I can get it up to about 35mph with the drill. Also no sound when just the tach is connected.

I myself lubed the cable, very well all the way up the length of the tubing with chain oil, and it was still wet when I took it off the other day.

I have read your article before, it is very nice, but in your third picture, gears B and C are metal, while mine are a plastic. I believe I read somewhere that they are a nylon of sorts.

My first speedo, the worm gear was warped, which caused skipping and the loud noise. I have not checked this one to see if the same is happening, but it didn't look in nearly as bad of shape when I put it on. I will pull it off tonight and see if it is warped again.

 

The worm gear is part of the input shaft; if your input gear is nylon the inner part of the input stub should be nylon too.

Try a smear of white lithium grease on the odo shaft gear (where the big input gear meshes with it.)

And don't feel bad about "going through" 30-year old mechanical instruments. I've been through at least three tachs so far between my two 550s; one responded well to cleaning and lubrication; one was simply beyond hope, no amount of lube would make it stop screaming. The jury is still out on #3, but it's still in service.

 

So I opened it up tonight, hooked up the drill and listened. This time I could hear a faint grinding noise coming from the input shaft, but the whiring sound was absent. Checked the worm gear and it does not appear to be warped like the other one. I could actually feel something not rubbing right as I held the speedo in my hand, which has never been the case before.

I removed some of the excess grease from the worm gear that I put on last time and shot some Marvel Mystery Oil onto the input shaft while it was spinning. After the third shot, the grinding went away. Re-lubed the speedo cable as well.

I'll put it back on tomorrow and maybe this time the noise will stay gone for a few more months.

Guess it was the input shaft after all.