Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > What Electronic tacho will work on my DD bike

[Monty]

Racing scooters eh-hmmm-I remember a race Lambretta (this was obviously a LONG time ago) which was about 18inches high-basically a kneeler like the sidecar outfit we used to race..............

John

[Chaz]

Have a word with Rich [luigi moto] he's fitted a 916 r/c to his dd bike.

Chass.

[skidlids]

Chass I gave Rich a call and had a chat with him, although the 916 revcounter is on the bike it isn't fully connected yet, just the oil light is wired in so Dom like myself and a few others has to do without for now.

[Felix]

My 2 cents.

I think the later tachos, such as those on the 916 and SSie bikes, are electronic ones using a stepper motor. These are powered by a 5 Volt signal from the ECU. The carbed bikes, I believe use a analogue 12 Volt driven tacho. If you simply try to hook up the 916 type to a carbed bike on the primary of the coil (or the output of the ignition relay), it will over drive the tacho, which in turn will sap the output to the ignition coil. This would explain why Alan's bike only ran on one cylinder. As a simply, and I think safe experiment, you could try to put a simply resistor divider between the relay output and the 916 tacho input, say a 7.5kOhm resistor from the relay output to the tacho input and a 4.7kOhm resistor from the tacho input to ground.

Might be worth a try.

[skidlids]

Thanks for the info Felix, I was thinking of linking the signal to the ignition coil to a 40106 or a 74HC14 invertor chip and using the output side to switch a FET on and off, with a few resistors & the odd capacitor thrown in and may be a 7805 voltage regulator if its a 5V signal I need to the 916 revcounter.

[domski]

Originally posted by skidlids
Thanks for the info Felix, I was thinking of linking the signal to the ignition coil to a 40106 or a 74HC14 invertor chip and using the output side to switch a FET on and off, with a few resistors & the odd capacitor thrown in and may be a 7805 voltage regulator if its a 5V signal I need to the 916 revcounter.

Yep, sounds spot on to me Kev

[Felix]

Kev, I am not a 100% certain about the voltage level on the 916 rev counter but vaguely remember measuring it once. I'd try the resistor divider before doing the more elaborate circuit.

[skidlids]

What I will try and do is get a Oscilloscope on mine and check it and then see if I can get it to work off my pulse generator.

In the mean time i have just found some research

http://www.jefferies-au.org/ECU/progress.html

http://www.jefferies-au.org/My16M/index.htm

[skidlids]

still researching

From above site
29 Mar 2002
Added some circuitry to drive the tacho. The tacho seems to have some circuitry of its own as all you need to do to drive it is give it a pulse stream

All useful stuff

http://www.jefferies-au.org/My16M/tacho.htm

[Edited on 12-5-2005 by skidlids]

[skidlids]

Isn't the web great for research
Your not going to find this down your local libary
http://www.tuneboy.com.au/Compare/Compare.html