'06 Sprint - 18T Sprocket - GPS Readings

[BallaRAT_ST1050]

Just did this 'great' little upgrade on my bike
What a difference it makes:
Much better for low speed 1st & 2nd gear turning and take-offs, only an increase of about 200 rpm (at cruising speed of 4500rpm) and much better acceleration and gear changes.
$35.00 AUD for the 18 tooth sprocket, borrowed a 36mm socket and undid it with a standard 10" breaker bar (much easier to loosen nut than I was led to believe it would be)
Now I know that these speedo's are not the most accurate so I thought I'd better check it against my car GPS, after dicking around and getting it set up on the bike I went out and did some runs on the back roads.
These will obviously be in Km/h



As you can see there is a fair difference, I now work on the 10% rule
Hope this is helpful for the guys who have gone for the 18T front sprocket.
I must say, even though it throws the speedo out a bit it is still a great upgrade - performance wise

[oldndumb]

Way to go!

The 18 tooth sprocket is the most performance bang for the buck that you can do. I found that it made the bike run like it should, and easier to handle during low speed maneuvers.

The 19/42 is too tall for the bike unless the majority of your riding is in 6th gear.

[RexxyPup]

More importantly, doesn't this mess with the accuracy of the odometer for your mileage and servicing?

Perhaps this is one place where a speedo healer is useful, although it appears that the Tuneboy software will allow you to adjust this in the ECU. It's just that Tuneboy is 2-3 times the price of a speedo healer

Rexx

[Triple Ripple]

I would think that simply changing one sprocket size would change the error in the speedo readings in a more constant manner. The non-linear readings below 60 km/hr are disconcerting. (Sorry, I can't figure out how to paste the graph into the message.)

[oldndumb]

Originally Posted by RexxyPup

More importantly, doesn't this mess with the accuracy of the odometer for your mileage and servicing?

Perhaps this is one place where a speedo healer is useful, although it appears that the Tuneboy software will allow you to adjust this in the ECU. It's just that Tuneboy is 2-3 times the price of a speedo healer

Rexx

If you know of a way to install a speedo healer to fix the speedometer and odometer please share it with us. I haven't been able to figure out how to do both.

[RexxyPup]

OnD,

I'm assuming this is for the 05- Sprints where the signal is off the output shaft as I think you have mentioned somewhere else on the forum.

If you change the gearing on such a setup, won't you screw the odo and the speedo by the same amount? hence won't a speedo healer correct both.

I assume that is why the 1050 (ThroughTuneboy Software) has an adjustment factor that you can alter.

It's only on my 955 (where they are driven from the front wheel) where the odo is +0.1% and the speedo +10% that you can't fix with the healer.

Rexx

[oldndumb]

Originally Posted by RexxyPup

OnD,

I'm assuming this is for the 05- Sprints where the signal is off the output shaft as I think you have mentioned somewhere else on the forum.

If you change the gearing on such a setup, won't you screw the odo and the speedo by the same amount? hence won't a speedo healer correct both.

I assume that is why the 1050 (ThroughTuneboy Software) has an adjustment factor that you can alter.

It's only on my 955 (where they are driven from the front wheel) where the odo is +0.1% and the speedo +10% that you can't fix with the healer.

Rexx

I do not have any experience with any of the speedo healers other that what I read on their web sites.

You are correct that speedometer and odometer readings are affected by the sprocket change.

The 05-07 speedometers are optimistic from the factory, but the oddometers are accurate.

The speed sensor signal is common to the circuit board. Then the input is split on the circuit board to feed the speedometer circuit and odometer circuit individually. So if you start with a speedometer with a 10% error and an accurate odometer, and apply a correction to the signal, you will end up with an accurate speedometer and odometer with a 10% error.

I believe that the Tuneboy has the ability to apply corrections to individual cells or rows.

CLB or DEcosse can explain it with more clarity and authority than I can.

[RexxyPup]

If you start with a very optimistic Speedo and an accurate odo, and change the gearing, you change both of them by the same error, so using a speedo healer in this circumstance will allow you to compensate for the error introduced by making the gearing change.

you will in effect be back where you started in terms of speedo and odo errors, but have different gearing. At least this way you can return your odo to the accuracy it had before the gearing change.

The only thing common across both bikes appears to be that you can't change odo independently of Speedo.

In Tuneboy there is a single field that is called the wheel speed constant that allows you to alter the figure to remove the +7% that comes from the factory, and also compensate for gearing changes. It's on p28 of the tune edit documentation

The tuneboy corrections to individual cells or rows is about altering the fueling maps etc

Rexx

[oldndumb]

[quote=RexxyPup;883566]

you will in effect be back where you started in terms of speedo and odo errors, but have different gearing. At least this way you can return your odo to the accuracy it had before the gearing change.


I see what you are talking about and agree. I guess I have never worried about it because I don't use my speedometer, and only use the odo for maintenance periods.