RPM at speed

[Doc]

I need some assistance from a 2V 900 owner.  I'm trying to calibrate a new tachometer and need some info from someone with a similar bike.  I have a carby M900 (1999 - the one without the tach dammit) and just put on a digital tach.  How many RPM are you guys running at 60, 70 or 80?  According to my tach, I'm running about 2600 RPM at 80 in 6th gear.  That seems a bit low, especially for a bike with an oversize rear sprocket.  But the bike does not feel like it's running 5200 either; which is the other option for a tach set up for single spark/revolution vs dual fire. 

So...

What do you tachometers read when running at 60, 70 or 80 in 6th?

[Dirty Duc]

5200 sounds reasonable to me... I think I have the same tranny gearing as you, and with 14/42 I'm at 5500 at 80.

[bdub]

injected here
I'm about 3800 in 5th at about 60

[Slide Panda]

What final gearing are you running? You say the rear is over sized - but numbers count.

[Doc]

Front sprocket is stock.  Rear is a 41 tooth.

[Speeddog]

http://www.bikeboy.org/ducgearing.html

Chart at the bottom, gives you rpm at 120 km/hr in top gear for various transmissions, primary and final gearing.

[Doc]

Thanks!  This helps.

I recalibrated the tach last night so it is reading 1 pulse/crank revolution instead of 2.  

With my 15/41 setup, the chart indicates I should be running about 4800 at 70 in 6th gear.  With my readings now doubled, the 2600 or so that I was running at 80 will be about 5200 at 80 in 6th.   That's closer to where it should be.  

Thanks for the help.