Speedo correction / Speedohealer / changed gearing on 4th gen

Hi folks.

I spent quite some time searching the forum for a satisfying answer to my question but couldn't find one... So I hope you bear with me when I start a new thread for this.

So I need a new chain kit. I decided to go for a gearing of 16-45 this time and therefore installed a speedohealer. Cheap and easy, done in a few minutes. So far so good. Now - I would also like to compensate for the factory speedo error, which gives me a bit of a headache as I don't have a GPS or any other way to measure the difference between real and displayed speed.
I have to values from another forum: People there used -9 and -9.4 %, respectively (also with 16-45 gearing). As far as I can see, this would mean an included factory error of + 5.5 %.
Now my question would be: can one expect this factory error to be the same for all 4th gens or would you have to measure it individually to be sure? Does anyone here have an accurate measurement of this for his 4th gen? I'd be really curious to see multiple measurements on individual bikes...
So what do you guys think? -9.4 % good?

On another note, I read somewhere else that for some strange reason the speedo on the 4th gen is off while the odometer is spot on. Thus, installing a speedohealer can either cure one or the other. This does not make any sense to me as to my knowledge the odo values are based on the speedo....? Any thoughts on this?


Well, I thank y'all in advance for your help and send greetings from Valais!

Cheers,
Tobias


P.S.: The Quick Mick has done almost 90'000 km now and runs smooth.

 

The phenomenon of the speedo being off and odometer being correct is not just on your 4th gen. It is common with almost all bikes, at least all Japanese bikes anyway. So yes if you use a SpeedoHealer to correct your speedometer, your odometer will be registering incorrectly.

When I changed the gearing on my '99 I simply installed a bicycle computer. It's much cheaper than a SpeedoHealer, and both odometer and speedometer are spot on. Cost me about $15. The only downside is that it can't be read at night, but I very rarely ride at night so that is a non-issue. Here's how it looks:

 

Thanks, mate.
I was thinking about a bicycle computer but I already have the SpeedoHealer now, so.... Plus, I'm not a big fan of mounting additional stuff to the cockpit or bars.
Ok, regarding the speedo/odo mystery: I hear you - but how is this technically possible? They are both fed the same signal, aren't they? I just don't get it. And besides, my speedo is definitely off (at least in Europe they have to go faster for legal reasons) but the odo also seems "faster" when I compare it to distance markers on the side of the road (not very accurate, I know). Also, I've been riding bikes for almost 20 years and have never heard of this phenomenon anywhere before.
I'm not doubting your words - just extremely surprised and curious.

But back to my actual question: calling all SpeedoHealer users!

 

I use stock gearing (16/43) with a Speedohealer and my correction is -6.3%. And yes, my odometer is reading low now by about 3%.

Choon

 

Thanks man - this more or less backs up what I heard before. I still don't understand how the speedo/odo difference comes about technically, but oh well. Some things you just have to accept.

 

They have different firmware in the ECU. The ECU gets the same signal but calculates both differently, one calc for the odo to be actual and one for the speedo readout to be 3-5% low. Lots of theories on why bike mfgs do this but it is well documented they do.

I added a speedo healer to my '99 after a gear change and adjusted it to bring the odo back to accurate and the speedo was around the factory original of 4-5% low. 75mph indicated is about 70-71mph actual going by my gps. Same as before the gear change, and odo remained unchanged before and after. Speculation is it has something to do with mfgs liability re: speeding tickets but who really knows.

I was more concerned with an accurate odo, some people may want the opposite, the speedohealer gives you that option.

 

Thanks for clearing this up! Didn't know that the ECU treats the signals differently but it makes sense. I gathered some more info on this matter and it backs you up.

With regard to the faster-running speedo, I don't think this is true for the US but in the EU and other countries it's regulated by law: speedos must never read lower than the actual speed but may read faster by 10% (+4 km/h). I guess the manufacturers just apply the same settings regardless of where the car/bike is sold. The reasons are, as you pointed out, liability and "safety".

Anyway, I think I will do as you did: just correct for the changed gearing and keep everything else as was.

Thanks again for taking the time to answer!

 

That's a nice simple bike computer. Brand and model?

 

It's a Sigma Sport. I don't know if they still make that particular model, but just about any one will work.

 

Blackbirds show 107 kmhr at a true 100 km/hr.
7% error.

My 94 VFR has 15:44 and speedo and odo are
way out. Over 5km there is a noticeable error in the odo.