Speedometer Problem

So I am having a problem with my Speedometer. The speedometer moves it just does not read correctly. When I start moving the indicator moves, but the MPH is always wrong. The MPH never seems to go past 35. It seem to always move up as I accelerate just not correctly. Is it just the cable? Any suggestions?

Thanks

 

Could be several things. Cable might need lubed, cable might be shot. The lube in the speedo from the factory might be turning to glue, might try cleaning up the worm gears. Is it making a horrible noise? Mine did that, had a cracked gear, lubing only quieted it for a day or so. I'm not convinced these speedometers are that accurate to begin with.

Have you pulled out the cable to make sure it's in one piece? Also, the sheath it runs through shouldn't have any holes.

Make sure the cable is screwed into the back of the speedo far enough, if the square end that turns the gears is popping in and out due to not going into the hollow shaft thingy far enough, (unlikely, but...) that could mess it up.

I just went to a used parts place and put a different yamaha(seca, virago?) speedo in mine, but I lost my trip odo, because it wouldn't fit

 

It could be a dry, loose or damaged cable.

It could also be the instrument itself. It can be cleaned and lubed.

Since we have no idea what bike you have, I can only tell you this:

Here's http://xjbikes.com/Forums/viewtopic/t=15303.html what's in there; you'll have to take it from there (getting it apart to get to the guts.)

 

defenitly going to have to go through that thread. as my speedo is also slow. i think 55 is the highest i've seen it. i had a rider along side and he said 80 was our speed.

 

It is an 1982 XJ750J. Well I am buying a new cable so we will see if that works. If not I guess it may be the instrument it's self. Very nice break down of the gauge. The gears do not seem to be making any noise at all.

Any more advice?

thanks

 

Sure.

Be sure to lube the new cable; do NOT use WD40. Use a high quality spray cable lube or motor oil.

The instrument itself may need to be lubed as shown in my article; if the bushing for the needle cup spindle is gummy the instrument will read slow.

It appears from looking at the parts fiche for your bike that the instrument panel will come apart and allow you relatively easy access to the gauge guts. If it's still sluggish after you fit your new cable, dive into the instruments.

 

dive into the instruments. your wasting money on the cable. the old one pulls out of it's housing. so if it ain't broke. there's nothing to fix. and you can tell if it's broke by taking the two ends off and twisting either end of the cable.

 

Well if the old cable is not broken could it be gummy as well and the instrument? Would spraying with the high quality cable lube fix this? If the cable is 28 years old would replacing it be a good idea?



Thanks again.

 

the problem is in the instrument. i've already gone though ALL the motions. it wouldn't hurt to pull the cable out and clean off all the gunk. and spray carb or brake cleaner down the insulator housing.

but the instrument is no good. and i've only found one shop in ohio that will fix it for $125 plus $25 shipping.

the drive mechanism and all that is pretty forward. either it works or it don't. the speedo instrument on the other hand is a different story.

 

I have a similiar issue...speedo works...seems to be accurate at lower speeds, but with my GPS strung around my neck at what the speedo noted was 80km/hr, GPS had me more like 94km/hr. I moves at all speeds...well atleast as high as I've had 'er so far

Cable is in one piece, will clean and lube it and see where it gets me.

 

speedo's aren't accurate. they'll most always be faster by about 10 percent. never seen one that was actually slower yet. unless something was changed to make it slower.

 

What kind of lube should I use for the Speedometer Cable? I went into Schucks Auto Supply today and asked for some cable lube and they suggested WD40. I told them that I was told not to use that and then they had no other suggestions.

Thanks

 

These bikes do have a tendency to have speedos that run slow if they aren't lubed correctly. (search around, there's several posts about it)There is a free-spinning bell housing that is spun by magnetic force when the cable turns. So there's not a direct connection from the cable to your needle, that housing has to be spun by the rotating magnet(which is in turn spun by the cable) and not a gear, it doesn't take much to hold it in place, any gummy old factory lubricant will give just enough resistance to make the needle react a little slower. I've had these speedos torn into pieces figuring out what was wrong with mine.

As far as what lube on the cable itself, I just pulled mine all the way out of the sheath and put a coat of regular old motor oil on it. You should clean the tubing it goes in, while your at it.

Edit: I just saw that Fitz said pretty much the same thing, just click on the link in his original response, my money is on the speedo itself, not the cable. Usually if the cable is going you get some warning from a very bouncy needle.

 

In addition to the above advice, don't forget the hub
gear ass'mbly.
I had intermittent trouble that went away after I pulled the
unit apart-cleaned/re-greased-it.
Keep in mind that It will be slow to respond at first due to
the tendency to pack in the grease. But after a short time It will
act as it should.
I've checked my clock against our van and a buddies bike and
it's right on the mark-so I cant explain why it should not be accurate.

 

someone made a mention of govt law making it illegal to ACTUALLY have accurate speedos. probably becuase everyone speeds as it is. only cop cars get that luxury.

don't know if that holds true or not. but every vehicle i've ever owned or driven has always been about 5-10 percent fast.

before gps came along. i would watch my odometer with the mile marker signs on the freeway. for every 1 mile i drove the odometer would add 1.05 miles. that's 5 percent difference. and on that note. EVERY vehicle in the world will actually have less miles then what the odometer reads. basically 5 percent less.

now that the gps has been invented. you can compare that with the speedo needle on your vehicle. since gps is satellite based. it'll be more accurate.

 

I can't imagine a law like that. If it were true anyone could
get out of a ticket or sue the manufactor.

Mile markers are not always that acurate. I drive belly dumps &
10 wheel on many road builds and know for a fact that they
drop them like most ground crews will-"thats close enough".
You can gain or loose a tenth or two at every marker you pass.
If the last marker was a tenth short and the next long by two, you just
lost three.