Speedo and Tach dissection with pics

The purpose of this post is to acquaint you with exactly what's inside the typical Yamaha mechanical speedometer and tachometer.
I am NOT advocating tearing your instruments this far apart.

The speedo that got completely disassembled was in pretty sorry shape, it came from a "canned" unit off a '79 XS. The bike had been down at some point, the back of the speedo frame was tweaked and the input bearing was pointing a few degrees off center. I chucked it in my vise and whopped it with a non-marring hammer and it straightened out pretty well.

Anyway, here's what's INSIDE your cans or clusters:

Typical Yamaha mechanical Speedometer and Tachometer



How they work: Cable attached at "A" turns input shaft, which has magnetic head "B." The spinning magnet "carries" the needle shaft cup along for a ride, winding the needle return spring "D" as it moves the needle "E."



Tach and Speedo work the same, except the Speedometer has ODOMETERS added, the trip odometer is already off both speedos used in this case, it makes it easier to see the other "guts:' Input head "A" turns worm gear "B" that drives shaft through gear "C" and turns odometer "D." Gear "E" drives the trip odo which is removed on this one. (It attaches at the blue arrow)



So let's take one APART! On most of the newer units that you'll find in the XJs and FJs parts "A" and "B" are swedged in place and can't be removed. I took this one apart so we could see what's inside where you normally can't see. It helps with the lubrication if you know what you're doing "blind." Needle "C" is pressed on a knurl on all of them that I've taken apart. I try to avoid removing the needle whenever possible.



The critical part you REALLY can't see: The needle shaft "cup" rides on a pointed spindle in the bell of the cup; it's supported by a bushing and the support "bridge" will be swedged in place on most newer instruments.



The other part you normally can't see: The support bearing for the cup spindle. See how gummy it is?



The needle shaft knurl: If you DO pull the needle, I recommend a 3-molecule microdroplet of adhesive on reassembly.



WHAT YOU CAN DO: CLEAN and lubricate. For cleaning, mineral spirits or paint thinner and q-tips; lots of q-tips.
MY PREFERRED LUBRICANTS for instruments:



Lube the INPUT BEARING here: (Remember, tach and speedo the same)



And here: Lube goes between the inner and outer parts. The hole is just for the cable and is blind.



TRYING to lube the blasted spindle and support bearing is the challenge; you have to feel for the spot with the tip of the straw.


Tach:




Speedo:



SPARINGLY lube the needle shaft bushing; jam a q-tip in there to
sop up any excess:

Tach:




Speedo:




Cleaning and LUBRICATING both tach and speedo can resurrect a failing or sluggish instrument.

LUBRICATE SPARINGLY. THINK IN TERMS OF DROPS

Put a DAB of silicone grease (JUST a dab) on the various gears, reassemble and test.

Hopefully, knowing what's inside there will help you save a speedo or tach.

 

Bigfitz, you all ways come up with the best looking pics. Nice job. If anybody has any questions about speedo or tach. They have a step by step look before they tear it apart.

 

Very nice, my friend! Thanks for putting this together for the XJ community.

 

Another awesome guide Fitz! Thanx!

 

Bumping this thread, as I'm finding it timely due to my own howling speedo. Looks like there's a wee bit more to lubing the thing than first meets the eye.

I've taken the liberty of making a PDF file out of the post; I'll be sticking it online probably tomorrow sometime. And yes, Fitz, you're listed as the author.

 

Okay, here it is. Could have made it smaller than I did, but I liked the detail so much I kept the pictures big.

Speedo breakdown

Enjoy.

 

Schmuck, you are indeed an artiste. Very nice work, thank you.

 

is there a quick and dirty way of doing this? Lube it without taking apart everything?

 

Others have suggested removing the speedo cable and shooting lubricant up where the cable connects into the speedo itself -- and I did try this myself first -- but there's no guarantee that will fix the problem. If it doesn't, then you're left with little choice but to pull it apart.

 

How do you get the trip knob off to let the speedo out of the housing

 

It's reverse threaded; you unscrew it by turning it clockwise. You may need to slip the tip of a pair of needle nose pliers in and hold the other end if it's reluctant.

I can't believe I left that out, and more importantly out of this one too: http://xjbikes.com/Forums/viewtopic/t=14948.html

Will have to fix, thanks.

 

Hey, glad I could help. When the cluster is apart, is there anything in particular that I am looking for. My tach is jumpy, and my speedo was making an awful whining noise. I took it apart and did the ole clean and lube, but now my tach is still jumpy and the speedo no longer whines (it just doesn't work). the cables are fine.

 

An FYI for you -- the knob for the 750J has a teensy-weensy screw deep down inside that holds it on. Consult "gauge cluster breakdown" for details.

 

Thank you guys for the detailed instructions. I will be trying this on my 82 xj650 before I just go waste money on a used cluster.

 

Thanks. Really helped!

 

Taking the needle off is alluded to...is it necessary or desirable, and if so, how do you do it?

Also, I can't quite tell, is the odometer independent of the speedometer? It looks like maybe they are driven by the same cable (of course) but different mechanisms.

 

Fitz, I did a write-up on getting into the xj700/xj700x/xv-style housings awhile back. You may want to add that to you write-ups. If you want it, I'll get a url for you to get right to it.

dave fox

 

I'd like to see the write ups, my speedo is confirmed 20 mph under at 75mph.

I need to know if I would be best served by removing and reattaching the needle, and am very curious if the odometer is still correct, because it's directly driven and not slipping like the speedometer is.

 

My write-ups won't tell you how to do anything inside the gauges, and they are not for your bike anyway......

dave

 

Is this still posted somewhere? The link seems to not work anymore.

again, great write up fitz, certainly another to print off and put in my binder!

Thanks again!!

 

go to xj4ever.com, schmuck keeps them parked there

 

I hate to dig up an old thread...... But I have an issue with my tach squealing like a spun bearing.

I've disconnected the cable to my tach since it started. I have not torn apart my instruments yet. Do any of you think this is all I need to do in order to resurrect my ailing tach?

 

i had an issue trying to get the needle off the tach as it snapped in half, so now i just have a stub. i tore down and replaced some insides with different ones because i have an electronic tach and the haynes manual says nil about it (so frustrating) and i bought a gauge cluster for a "1982 yamaha maxim 650" but of course when i got it it had the tach for a cabled system so that was great. i couldnt get the needle off, and slightly bent something i think because the needle now rests initially just under the 0, so im always slightly off. not taking that dang thing apart again. just dealing with it until i can figure out some other gauges. frustrating to say the least.

 

I could put it up on Chacal's site, but it's up to Fitz to decide whether he wants me to do that or not. It's his writeup, after all.

Not Fitz's, I don't. Need permission first.

 

Schmuck, the link to my "how to" still works, it's this article right here.

The link he's talking about is a link to the site you don't use anymore; a PDF entitled "speedometer breakdown." All of my stuff is still alive right here on this site; we haven't converted this one into a PDF yet that I'm aware of.

 

That much is obvious. What I hadn't noticed was that the post I replied to was 13 months old.

I had; hence the link.

 

Hey I was wondering if someone could share some insight, with me. My speedo isn't working but the odometer is and we took it all apart and it looks exactly like the picture. Everything is moves and isn't stuck the magnetic head "B" spins but its not spinning the shaft cup. I can move the shaft cup and everything else moves above it. Its hard to see what is going on in the shaft cup because of that bar, Anyone it would be a lot of help I'd rather try to fix it then get a whole new instrument custer and maybe have the speedo not work again lol

 

The cup spins independently.... Now when I say that, keep in mind that it spins at a different speed too--- it seems to spin at a different speed to create the relative drag (magnetically, if I remember correctly) to calibrate correct speeds

 

The cup doesn't "spin" it does rotate to move the needle.

It rotates in response to the spinning magnetic head "dragging it along" via magnetic pull.

If the magnetic head is spinning but it's not moving the cup, it has likely lost most of its magnetic properties OR the cup/needle shaft/bearings are so gummed up it can't move in response to such a light pull.

 

That's exactly what I was trying to describe.. " Slowly Rotate" is a better way to say though. Maybe even better-"slow rotation acting as a damper"
Dave

 

Correct.

The actual damper is the clock-spring. Which is why (if it's been apart) initial needle position is uber important since the preload on the spring is what resists the needle from slamming the peg on the top end as soon as the magnet spins, plus the needle itself is the "downstop."

However, I failed to mention that if someone before you had the instrument apart it could have been incorrectly reassembled.

If it is indeed an original part, I'm betting it's gummed up over anything else.

 

On some models the needle stops against a very small plastic pin that sticks straight out from the face.

 

None of the links seem to work, unfortunately. I'm having a difficult time with my speedo, and came here for help. It's whining, vibrating, and having a terrible time! I had to unhook it today, just to get home. But I would love to be able to fix it without taking it completely apart - is that possible??

 

Katherine, it depends on which model of bike you have. Some are easy to open up, and others are labor intensive. Let me know the following:

1. what bike you have
2. where you're located

If you're close by, (I'm near Utica, NY) I could possibly help show you what to do....or you could send it to me and I could go through my parts and see what could be replaced; or you could just get a replacement from Len Chacal, or ebay, or etc.......

As far as links--we just went through a complete migration, and we are still working on getting things back up and running. Much of the info is still on the old server and has not been all brought over yet.

Dave Fox

 

Thanks so much, Dave!

I have an 85 Maxim X, and am located near Anderson, Missouri (a bit too far from you, unfortunately).

I actually took the speedometer off, and tried to clean it up a bit, and put it back on the bike. It then worked for about 4 hours before the whine came back! I'm pretty sure I need to get into the case, though, but I'm a bit nervous about getting the bezel off and back on.

Once I got the speedo off the bike, I found that I actually had a broken reed switch - do you know where I can get a replacement for that? The glass is broken, as well as the plastic holder for it. I have made it a habit to cancel my turn signal, but I would really like for it to work again!

I've looked over your illustrated article, "Gauge the results for yourself", and find it absolutely wonderful! Thank you for the in-depth guide. KUDOS to you!!

 

You're welcome! Yeah, if you have an X, then that is the only day to get in there shy of cutting the plastic in half. For the Reed, contact Len Chacal at xj4ever.... That's who I got mine from......

 

Well, I've done it now!!

Tore into the speedo, and cleaned it up a bit. It seems everything was fairly functional, just a little gummed up. I seem to be having the most problem at the input shaft. It was a bit difficult to turn, and since I've cleaned it out some, it seems a little "loose" - is that how it's supposed to be? I've been trying to clean it out (as best I can), and when I have the cleaning solution in there, the shaft spins easily. Once I spray it out with the compressed air, then let it sit awhile, it is difficult to turn again. I have not yet tried to lubricate it, as I want it to be thoroughly dried out. Suggestions???

Also, I have looked for a lubricant similar to one you have pictured in this thread, but couldn't find anything with teflon. I found a silicone spray with "cerflon" (Liquid Wrench product), and after doing a little searching, found that this new ingredient is similar, and I think I read that it has teflon in it. Have you ever heard of this? Would this be a good lubricant for this application?

 

If you're gonna try to spray some lube in there, look for a white lithium spray grease.

Dave

 

I've updated most (98%) of the links to some of the most relevant "how-to" or useful threads, please visit:

http://www.xjbikes.com/forums/index.php?threads/the-information-overload-hour.27544/

and, of course:

http://www.xjbikes.com/forums/index.php?forums/xj4ever-supporting-vendor.23/

 

Excellent write up BigFitz - I have taken my speedo apart several times due a few unfortunate issues like that squealing others have noted (during low speeds and cold weather). Both my needles decayed from age and have been replaced with toothpick substitutes, but now that I have a decent low mileage replacement speedo/tach unit my question is - is it possible to swap in the original odometer? I'd prefer to have the original odometer reading (85,000 and counting) for accuracy's sake.

 

Yes, you can swap the odo. OR you could simply reset your replacement to match. It's not difficult; but changing odometer readings is highly illegal (even for legitimate reasons) so I won't post a "how to" here.

BUT (if) you were to PM me with an email address (that may or may not be yours) I might (allegedly) be able to send you the (theoretical) procedure that I (may or may not) have for changing it.

 

If you look very carefully at how the odometer works you may figure out how to "adjust" the new one to read actual mileage without damaging it. Let's just say that no parts have to be removed from the odometer to make this process work. To keep it legal you will need to have a shop do the paperwork for an odometer adjustment. That is sometimes difficult as most shops want to sell the parts and do the adjustment themselves.

 

Very interesting - looks like I have two options, but I'm wondering if the legality issues only come into play if I sell the bike someday. As I've had it 27 years and counting, I bet that selling it as a saftied "on road" vehicle is never going to happen. I rode it into the ground by 2000, restored it, and will likely ride it into the ground again. But I would like to see that odometer roll over whether its the original parts or not.

Just a note - when I purchased the Vmax, the owner noted that it had a replacement odometer that did not show the correct mileage - but he had some paperwork to show what the old odometer had prior to replacement that was part of the used vehicle sellers package you need to get here in Ontario. I had to sign an acknowledgement of that fact so there was no misrepresentation of the actual vehicle mileage. If my Seca will be showing the correct (documented) mileage under either type of modification, I wonder does it matter?

 

When I got my motorcycle the PO had installed an aftermarket speedometer/odometer to the handlebars - which prevented me getting a safety on the bike as it hit the gas tank regardless of where it was positioned. I seem to recall the MTO telling me to just add up the readings from the two odometers for the total mileage on the bike.

I've since cleaned and lubed the original speedometer (wish I'd found this thread beforehand, but I used to fix photocopiers so it was a walk in the park; only aesthetic issue is I greased everything including the numbers) and removed the superfluous unit - any thoughts regarding what will happen if/when I sell the bike? The sum of the two readings was ~110,00km. Just hit 50,000km on the original (and only) speedometer yesterday.

 

I'm 2 days away from a 3,500 mile trip and my speedometer broke yesterday. Its the B - worm gear that is completely shot now. Is there any way to get a new speedo on the fly? The needle was going crazy yesterday and snapped in half and when I took it apart today, that gear is fried. I'm more worried about counting mileage for gas than anything else.

 

Nothing you can do unless you find a replacement.... Just have watch miles carefully

 

As a

As a temp fix for your trip you could use a cell phone and a speedo app.
Been working for me until I can replace my worn out display.

 

I happened to find one on ebay in Lost Hills. He was stoked about my trip and is going to give me the whole cluster for free! I only need the speedo side, does anyone want the remainder of the gauges?

 

I'll be glad to take the gauge set off your hands!

 

Hahahaha.......look at that!!!! Len beat me to it------