How accurate or otherwise are the std speedos on VTR's ?

[sirch345]

I was able to reach a bike speedo indication of 199.9mph.

I must do that airbox mod

[Tempest]

Reason I ask is I have a 15t front sprocket instead of the 16t one. Wondered how far out it is to start with before this mod was done.
I have a Sigma push bike speedo in the shed but am yet to fit it.

I had an indicated 140mph with more to come before I decided that the M20, err sorry, private test track was not the place to be doing this sort of 'testing'.

I can say that at a steady 102mph indicated it was reading 5,500rpm.
Is there a miles per hour per thousand RPM figure anywhere?

Mine was about 10% off BEFORE I started messing with sprokets.

Got a "Speedo Healer" doddle to fit, and now it's spot on.
Recommend one to anyone. (who has a Honda)

[VTRgirl]

My old Storm had different cogs... One tooth up on the back & one down on the front. A friend had exactly the same on his Storm. Both our speedo's read exactly 10% over what we were doing. Thought this was great until I realised my bike was clocking up 10% more kms on it than I was actually doing... Luckily, I sold it to a friend who took that into consideration.

I haven't changed anything on my new Storm yet, but I'm quite sure I'm doing faster than the speedo reads

[LotusSevenMan]

VTRgirl.
Yeah, I had that feeling the other day too

Then I fitted a push bike speedo (with incorrect cailibration) and saw 199.9mph on the clock. Much more like it ha ha

[Kitch]

I've just fitted a SpeedoHealer to mine (dead easy, if I can do it, a blind leprous wombat can)

I calculated that with one tooth down on the front, plus factory error, I was out by -12%

I'll need to raid a GPS from somewhere to get it exactly.

[LotusSevenMan]

Yeah Kitch I'm just about to get one too and luckily have a TomTom GPS so exact speed will be known OK!!!

Get those dip switches set.

[Kitch]

Having ridden around a bit with it, I think my calculations must be out. It just feels like its under reading now.

Either that, or my perception is off...

Anyway, the beauty of it is, it takes me 2 seconds to change it to -10% which should be better.

It might be over reading slightly (or not), but not by much.

[LotusSevenMan]

Mine arrived this morning with the added bonus of ordering the std recal-button-on-the-top-of-the-unit one but them being out of stock and supply the flylead button recall one at the same price! They seem a good outfit this Bikers Discount Store (Mike Burnside).
sales@bikersdiscountstore.co.uk

Now to get my info off the website as I know that an exact 80mph indicated is actually only 70mph in reality.

OK. This is the info for my set-up ( Which is std but for 1 tooth less at the front!)

SPEEDO HEALER

SH Calibration Value to be stored: -12.5%
SH Conversion mode Value to be stored: 0

- the ignition must be OFF
- set ALL SH switches ON
- turn ON the ignition
- press the button => memory cleared

- set ALL switches OFF EXCEPT #4
- press the button 1 time(s)

- set #5 switch ON
- set #4 switch OFF
- press the button 2 time(s)

- set #6 switch ON
- set #5 switch OFF
- press the button 5 time(s)

- set #6 switch OFF => all data stored in Flash.

Notes:
1. Please make sure to follow ALL STEPS EXACTLY, otherwise the unit won't be programmed properly.

2. It is recommended to check the new value of the selected parameter on the LED before selecting and setting another parameter.

3. Should you need to abort the steps and return to the previously stored settings, turn off the ignition and then set all switches off.

4. Whenever the ignition is switched on with all sh switches down, the led should blink 2 times, meaning that there is a valid calibration value stored in memory. If you see rapid flashes for 3 secs at ignition on, the calibration memory is empty and the unit will start in Transparent mode.

5. If you wish to modify a previous set-up and change only one parameter (e.g. -8.4% => -8.5%), you don't need to issue a reset. To speed up the process, just change that one parameter only.

6. For more information, refer to the User's Manual, section 1.

Anything like your set-up KITCH?

[Kitch]

Pretty similar, but you'll have to see if you agree with me.

At 30mph on the newly calibrated speedo, it felt fast. And I mean noticeably faster than when I use to travel at 35 uncalibrated. As lower limits are more important from a speed camera etc view, I've backed mine down to -9.4 from -12.

I got -9.4 from giving a 5% factory error, + a gearing difference of 16/41 to 15/41 and used the "changed gearing" setting on the online calculator. It gave me -11.4 for speedo and -6.9 for odo, (speedos are usually factory innacurate, but odometers are usually quite spot on) with an average compromise of -9.4, so I'm using that and it felt better out on the road today.

So, I'm over reading very slightly, but only by like 1mph at low speed, but I'm happy with that and it's better than the 12% out it was before.

[LotusSevenMan]

Was yours a calculated 'error' setting then? It seems so from what you are saying Kitch
Well I have a GPS I can/have put on the bike (though as it's a TomTom Go 500 it's not biker specific one so sits in the clear section of a tank bag for these purposes) and also put on an accurate Sigma push bike computer so can vouch for the 80 indicated being 70 actual as two instruments said so!
I am, like you on 15/41 set-up sprocket wise.
That makes my -12.5 computation by the on-line calculator what you probably should have too given similar speedo instrument error of course.
Your educated guess at -12 seems to be pretty damn good. You could always use that -12.5 instruction above and see how that feels eh?
I agree the -9.4 would seem wrong!!!

[Kitch]

No LSM heh

t'other way round.

-12 is what it should be. With the SH set at -12, I went out for a ride around and when I'm sitting at 30, I'm pretty sure my speedo is under reading and I'm actually doing more 30.

Hence I reduced the conversion factor to -9.4 which feels a lot better.

My perception of speed is usually pretty good, -12 felt too fast, my settings now feel just right.

I doubt -12 is enough over to get into speeding trouble, but I'm happier with slightly less.

[LotusSevenMan]

Ah, I see. I did it another way using just the gearing conversion chart and came up with -11.1% so ?????????

Well I can check it with the GPS and the bike computer to see how good it is eh?

27-03-07
Just fitted the SH. Geez, not exactly difficult is it!!!
Have gone for a 12.5 as specified setting and I will compare it on the road with the GPS and the Sigma BC bike 'puter as a cross check. I'll let you know what it's like as soon as I get a ride in.