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Discussion Starter #1
I had installed the 15T front sprocket @ 1st service, and I've always been puzzled about speedo and odo accuracy since then. I finally tested with a GPS and speedo is still optimistic. @ 7,000 RPM speedo reads 100kmh (62mph) and GPS reads 96kmh (~60 MPH) ...GPS reads slightly lower for pretty much any speed.

My conundrum comes from gearingcommander.com which states, with 15T front gearing, @ 7,000 speed should be 104kmh (~65mph). With stock gearing speed @ 7,000 should be 97.1kmh (~60mph)

I watched Anthony Compton's youtube clip showing his bike running @ 7,000 and his speedo reading ~60mph and I assume gearing is stock - he doesn't say otherwise.

So I'm wondering if the bike shop accidentally installed the wrong sprocket...I did get back the original 14T in the package that new sprocket came in - and the part number refers to a 15T PowerDrive sprocket. I like to think that gearingcommander is accurate.

So before I remove the countershaft sprocket cover and count the teeth, my question is, what is your accurate speed @ 7,000? And are you running 14T or 15T front sprocket?

Thanks in advance...this is driving me nuts.
 

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My bike shows 60mph on my Garmin Oregon 450 gps at exactly 7000rpm and I have a 15t cs installed. The bike speedo reads right at 63 mph at 7000rpm...so, it is reading 3 mph faster than the true speed.
 

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Keep in mind that changing the gearing has no effect on the speed reading the speedo displays.
This is because the speed indication, for both ABS and Non-ABS models is sourced from the Rear Wheel Rotation Sensor. The ABS model also uses the RWRS as part of its ABS, but the Non-ABS model has an RWRS as well - just for the speed reading.
As per normal practice, the VX 300 speedo reads about 4% optimistic.
 

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Discussion Starter #4
Thanks Brockie and whsperquiet for responding - from that I won't remove the cover to count the sprocket teeth. This all makes sense now if all speed data is coming off a RWRS.

I guess I put too much expectation on gearingcommander data which are perhaps theoretical calculations and not real world conditions. I'll sleep better now :)

BTW, if anyone wants to further share their GPS speed @ rpm, along with their gearing, I would be interested.

Thanks again.
 

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100kph indicated = 6,800rpm. Gearing 14/42 on OEM tyres.
 

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If speed indicated is derived from rear wheel sensor then the gearing will still I make a difference when revs are compared to measured speed. If you reduce gearing by 10% then you should see a 10% increase in revs for the same wheel speed.

Plus your rev counter is often not very accurate. I have another bike that over reads revs by 300rpm everywhere !

Gearing commander uses an assumed tyre circumference, your tyre may not be that specific circumference. So you should run the gps against speedo & rev counter on the stock gearing & then adjust the gearing commander peramaters to be correct for your setup, then play with alternate gearings.

As they say YMMV.
 

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Discussion Starter #8
Thanks Mohawk and Fastoman,

I think my rev counter is pretty accurate. And Fastoman, I've studied gearingcommander to death, which is why I got into this quandry in the first place.

On another note, I have a OBDll Bluetooth reader for my car - works great with Torque Pro app. It has an accurate tachometer as well as GPS vs Speedo guage.

I notice that Torque Pro can also be configured for motorcycles. Anyone know of a Kawasaki OBDll (Bluetooth) reader? I should Google that...
 

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Thanks Mohawk and Fastoman,

I think my rev counter is pretty accurate. And Fastoman, I've studied gearingcommander to death, which is why I got into this quandry in the first place.

On another note, I have a OBDll Bluetooth reader for my car - works great with Torque Pro app. It has an accurate tachometer as well as GPS vs Speedo guage.

I notice that Torque Pro can also be configured for motorcycles. Anyone know of a Kawasaki OBDll (Bluetooth) reader? I should Google that...
I did look up on the OBD reader for kawa, but in vain....if you come across , let us know. Meanwhile enjoy your ride and be safe.
 
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