Tachometer Accuracy

longhorn · January 4th, 2012, 04:51 PM

We calibrated my tachometer on a fairly new Dynojet Dynometer yesterday and found it to read about 10% high. One cannot calibrate the speedometer on a dyno as the drive is off the front wheel; but after riding it and noting speed vs tach readings and calculating what it should read using Gearing Commander figures, it appears that the speedo is about right to within about 1 or 2 mph.

Both these results surprise me; I thought the tach would be more accurate and the speedo would over-read by about 6 or 7%.

Has anyone else tried to calibrate these instruments? I would be very interested in their results.

alex.s · January 4th, 2012, 04:56 PM

my tach accuracy varies wildly depending on ambient temperature. you would probably find better results from an aftermarket setup?

longhorn · January 4th, 2012, 09:10 PM

Alex, I noticed that too; it starts out about correct and then over-reads after about 2 miles. But idle is at 1,500rpm indicated anytime!

January 4th, 2012, 04:51 PM	#1
longhorn ninjette.org member Name: Nick Location: Tucson Join Date: May 2010 Motorcycle(s): 2009 Ninja 250R Posts: 20	Tachometer Accuracy We calibrated my tachometer on a fairly new Dynojet Dynometer yesterday and found it to read about 10% high. One cannot calibrate the speedometer on a dyno as the drive is off the front wheel; but after riding it and noting speed vs tach readings and calculating what it should read using Gearing Commander figures, it appears that the speedo is about right to within about 1 or 2 mph. Both these results surprise me; I thought the tach would be more accurate and the speedo would over-read by about 6 or 7%. Has anyone else tried to calibrate these instruments? I would be very interested in their results.

January 4th, 2012, 04:56 PM	#2
alex.s wat Name: wat Location: tustin/long beach Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much. Blog Entries: 5 MOTM - Oct '12, Feb '14	my tach accuracy varies wildly depending on ambient temperature. you would probably find better results from an aftermarket setup? __________________________________________________

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January 4th, 2012, 09:10 PM	#3
longhorn ninjette.org member Name: Nick Location: Tucson Join Date: May 2010 Motorcycle(s): 2009 Ninja 250R Posts: 20	Alex, I noticed that too; it starts out about correct and then over-reads after about 2 miles. But idle is at 1,500rpm indicated anytime!