Speedometer reading way off.. Help?

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expat · #1 Post by **expat** » Sun Aug 03, 2014 4:07 pm

I took the RZ for a shakedown today, I was doing an indicated 120 in top gear at 6K rpm...... Behind a Kia Soul!
Anyone know how to calibrate / check the speedo? I rebuilt my gauges and the one I originally rebuilt was not recording milage but was accurate to about 10mph (good enough!) so I just installed a spare speedo I have, this one records miles but the speed is way off and the needle once past 60mph seems to fall to the right when you go over bumps until it hits the stop at 120!
Any ideas??

Bare · #2 Post by **Bare** » Tue Aug 12, 2014 11:10 pm

These are in a word: Crap.
One can buy a V inexpensive Bicycle Speedo /trip computer and fit it .
Very accurate but typically only capable of reading up to 99.9 MPH.
Good enough

JonW · #3 Post by **JonW** » Wed Aug 13, 2014 1:26 am

if youre going over 100mph, who actually cares the 'actual speed'? and... anyone tracking you will want your licence anyway and provide measured speed test paperwork....

expat · #4 Post by **expat** » Thu Aug 14, 2014 3:45 pm

I think I awash doing about 50 when it was reading 120! I read about adjusting the magnet pick up inside the unit. I have 2 speedos, I will mess with the spare one to see what I can get it to do. I can zip tie it to the bike somehow to avoid having to keep dismantling the clocks!
I will let you know if I manage to fix it!

If anyone has a decent MPH spare they are willing to sell cheap, let me know!

silverstrom · #5 Post by **silverstrom** » Thu Aug 14, 2014 5:46 pm

Not sure what you're after, but I have this one. Primary is MPH and odometer is miles.

PM me if you're interested.

John

expat · #6 Post by **expat** » Mon Aug 18, 2014 10:11 am

Thanks John. Mine is an 85 model with the kidney shaped clock housing and the trip pushes from the top, not the side. I appreciate your offer though!

evansje1 · #7 Post by **evansje1** » Mon Aug 18, 2014 7:15 pm

I finally gave up! If you are not looking for stock these Vapors integrate very well. Mine functions great. I installed the thermocouple in one of the water lines as well. The heat rising up from the hot engine does mess up the air temp reading.

silverstrom · #8 Post by **silverstrom** » Mon Aug 18, 2014 11:43 pm

expat wrote:Thanks John. Mine is an 85 model with the kidney shaped clock housing and the trip pushes from the top, not the side. I appreciate your offer though!

Once removed from the case the late model speedo is the same as the early model speedo other than the trip reset. The late model will drop right into early cases and you have either no trip reset or have it at the left side of the kidney shaped cover.

It's the same for the tachometer. Inside the late model case it is the same shape and size as the early model tach and will drop right into the early case. The late model is, of course, electronic, but that can be overcome and is especially easy if you have a Zeeltronic CDI.

Same for the temp gauge.

So, you can use late model clocks in US bikes once the late model clocks are removed from their cases/housings. A little known fact that I find interesting.

expat · #9 Post by **expat** » Mon Sep 01, 2014 9:17 pm

Ok, finally got round to tackling my optimistic speedo today.
I taped a Garmin GPS to my tank and went for a spin. The clock was reading 10mph fast at 30, 40 and 50mph.
I came home, stripped the clock from the housing and dismantled it as much as possible.
Using carb cleaner on a cotton swab I cleaned all the gears and magnet surfaces. I then lubed everything with a light machine oil and ran the speedo using an old cable in a cordless drill.
Finally, I positioned the needle at 40mph and marked the shaft and magnet to show alignment. I then popped the needle off, re-aligned the marks I made on the magnet and shaft then re-installed the needle reading 30mph (-10mph).
I reassembled everything on the bike minus the case in case further adjustments were needed and went for another spin with the GPS on. The clock on the bike pretty matched the GPS within a couple of MPH through 70mph. Success!
I reassembled everything and can be confident I am close enough to avoid riding too slowly!!

JonW · #10 Post by **JonW** » Mon Sep 01, 2014 9:52 pm

great news, well done on getting it working and keeping it original :)

hondaror · #11 Post by **hondaror** » Tue Sep 02, 2014 1:53 am

Excellent!

trappena · #12 Post by **trappena** » Thu Sep 04, 2014 6:14 pm

expat wrote:Ok, finally got round to tackling my optimistic speedo today.
I taped a Garmin GPS to my tank and went for a spin. The clock was reading 10mph fast at 30, 40 and 50mph.
I came home, stripped the clock from the housing and dismantled it as much as possible.
Using carb cleaner on a cotton swab I cleaned all the gears and magnet surfaces. I then lubed everything with a light machine oil and ran the speedo using an old cable in a cordless drill.
Finally, I positioned the needle at 40mph and marked the shaft and magnet to show alignment. I then popped the needle off, re-aligned the marks I made on the magnet and shaft then re-installed the needle reading 30mph (-10mph).
I reassembled everything on the bike minus the case in case further adjustments were needed and went for another spin with the GPS on. The clock on the bike pretty matched the GPS within a couple of MPH through 70mph. Success!
I reassembled everything and can be confident I am close enough to avoid riding too slowly!!

Mine started acting up some time ago, reading way off and the tachometer was also making some screeching noise. Took it off the bike and sprayed where the cable attaches some silicone and that did the trick.

Cheers.

RZ/RD 350 & Misc. 2-Stroke Tech BBS