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Speedometer shows too much

2K views 13 replies 5 participants last post by  RA5MU5 
#1 ·
Hi there!

I bought a 2nd hand FireBlade for about a month ago, and I have noticed that the speedometer is showing way too much. When i am driving about 130 km/h, the speedometer is showing 165 km/h. I have checked the sensor in the side of the front sprocket, but it seems to be intact.

I Have heart about a Speedo Healer, but the needle is very unstable at high speed, and I don't think it will help.

My bike is a '94 Honda CBR 900 RR FireBlade.

Have any of you seen a problem like that before?

Best regards
Rasmus, Denmark.
 
#3 ·
Bikes are notorious for having inaccurate speedometers. However, that's quite a bit. An example is if my speedometer reads 75 mph, I'm actually going 68 based on a GPS on the bike. I suspect that someone has changed the sprockets on your bike, which is a common thing. It's easy to count the teeth on the rear sprocket (or look for a number stamped on the sprocket). The front one you'll have to remove the sprocket cover which is held on with bolts.
 
#6 ·
It could have something to do with the voltage causing interference (EMI) and making the speedo go haywire.

One other thing to check is that your leftside driveshaft bearing is not wiped out. The sensor is a pickup coil like on cars and also contains the voltage regulator, so if you have other funny electrical stuff happening- that could be a place to look as well.
 
#7 ·
I had a '97 that was a bit of a basket case. It had a UK mph speedometer (labelled in 10's not 5's) fitted but the UK ownership papers showed "was registered in another country". Anyway, turns out there's a mph/kmh sensor available and you have to get the right one or it will read significantly off. Not knowing what I had, and wanting to change the final gearing anyway, I bought a speedo healer. Fixed it, speedo was then on accurate to within 1% of GPS at all speeds once setup properly.
 
#9 ·
@amorti

That sounds a lot like my problem. I found out that my bike is imported as well. So maybe it is a MPH sensor and a KMH speedometer?

Can a speedo healer fix my problem? I mean, it is i a huge difference to "heal". And is possible on my FireBlade, where the sensor is measuring on the front sprocket?
 
#11 ·
@rasmus,
I think you have the exact problem my bike had but in reverse. The difference was ballpark 25% and the speedo healer had no trouble with it. They can cover a Really big range!

So you either need a kmh sensor to get as good as original, or a speedo healer to get perfect. In any case a brand new bike will over read approx 8% and for me I prefer it to be accurate. So even with original gearing you would have an advantage by getting the healer if you agree with me.

However healers don't come up cheap but used sensors might do.

Your call! But I think the diagnosis is correct anyway.
 
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