What Electronic tacho will work on my DD bike
 

As my 600SS had to have a engine transplant, it ended up with a 600 monster engine and as such I had to dump the cable driven tacho.
I have a few ideas on fitting one but before I start mucking around and risking blowing things up, I was wondering what others have done, has anybody got a 916 one to work, or one off a latter SSie, obviously as its a budget racer I'm considering the cheaper options.
Otherwise I would be considering, Stack, Elliot, Scitsu etc.

Kev
What sort are you after, Reason i ask is we have just got in some hebo kit, Its digital and quite small, do an image search on google for "Gpt digital tacho" that should give you an idea.
If its any help drop me a line
Glyn

What about one of those Veypor things? They seem cheap enough. I guess though you'd have too much info on there for clarity.

Darren

Kev, the ie ones wont work because the signal from the transducer ignition relays is different to the normal type of signal. I put a 900ssie on our bike & even tho it read a signal - it cut the rear coil out completely, so was only running on one cylinder.
Even the dyno revcounter wont pick up the signal from the ignition relays (transducers)

I'm sure you need the early type rev counter fitted to the 900 carbed bikes to get it to work properly.

I also brought a shift light (L.E.D) unit & found I couldnt programme it, cos the lights just came on & stay on... more money out the window, but was a good idea & the salesman at Alli-Palli assured me it would work (dont they all?) but after cutting the wires to fit - I could'nt send it back.

Am still on the case.

Alan

Thanks for the tip Glyn, just had a search and found this
http://www.beedspeed.com/revcounter.htm

Base model looks very good value

But was hoping somebody had got a 916 onr to work, looks like i'm going to have to build a signal conditioning unit to pick up off the CDI output to the coil and get a nice digital pulse for the 916 tacho.
May just have to bolt my Stack on with its shift light and recall system, but its not in keeping with the project although it would give me a good idea how I should be gearing the bike which is going to be very important at the next two rounds

Alan if I get it sorted using a 916 tacho or SSie I will build a couple of extra circuits.

Yea beed speed is in the same town as us, but more expensive..LOL. we have just fitted one of them to our race scooter, Dont laugh, 50cc, 10inch wheels and 100mph. it really is going to hurt.
glyn

wicked, cheers Kev - if it works let me know, as i am running no revcounter at the mo - and cant afford another £100 odd squids for a DP one

Alan

You got a pic of this race scooter Glyn you were on about it at Cadwell so it must be ready for a photo session by now, you don't have to post it here just email me a pic.
And how much you selling those tachos for

Yea will get some pics sorted out for ya mate, its getting quite trick, and cost a bloody fortune, revs to 16000rpm:lol:
Engine alone has cost 1k, the little bugger better win on it.
Im still considering joining you on the grid again, i recon the DD series would suit me down to the ground, no stress just lots of good guys enjoying racing with out the pressure normally associated with racing.
As for the taco bell, i will have to check as we have 2 or 3 types in stock, the one we just fitted does everything(max recall, time run, temp) and i recon that was only about £60. the basic one should you would have thought been a bit cheaper, Another job for kirsty in the morning..LOL

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

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

Chass.

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.

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.

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 :puzzled::puzzled::puzzled::lol:

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.

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

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]

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

Great stuff, Kev! Amazing these aussies. Must be getting to much sun.:lol:

Yep I'm living/working in the wrong place, the aussies certainly get creative
Then again right in font of me now I have the circuit diagram for our gun modulator that we run at 300 pulses per sec but will cope with 2000 pps and as my DD bike red line is 9k thats only 150pps then I think I have most the parts I need here at work.

Alternatively:

http://cgi.ebay.co.uk/ws/eBayISAPI.d...3702 316&rd=1

Even better for you Kev!!:lol::rolleye:

http://cgi.ebay.co.uk/ws/eBayISAPI.d...9884 976&rd=1

I see that you have found the dyslexic ebayers too - but 15k rpm!!!

[Edited on 13-5-2005 by paynep]

[Edited on 13-5-2005 by paynep]

As I mentioned I could spend the money and fit an Elliot or use the Stack I already have, but its not in keeping with the project.

I have just had the 916 revcounter working on my 600SS, The bike ran fine but the circuit still needs some Select on Test (SoT) resistor changes.
At tickover it was reading about 400rpm and at full engine speed it only got up to 7000rpm.
Not a bad first attempt. I haven't yet measured the revcounter pulse on my 916 to find what level so on the prototype I went for a 6v pulse, this could be either 1 volt more than required or 4 volts less than required..
If I can find a suitable variable resistor I will put it in the circuit to allow me to experiment with differnt voltages.

oops,
Now going backwards, I haven't got that much of a choice of resistors at home so I used what I had, firstly I went for bigger voltage pulse to the tacho, this gave no reading at all.
So I then went the other way so I had about a 3 volt pulse going to the tacho, this caused the engine to run poorly, the tacho needle to jump about and then after about 30secs fried the chip in my circuit and melted the base it was plugged in to.
It looks like the original voltage of 6v was the closest and it may be the pulse length that is the reason the readings were falling short of what I expected.

Prototype 2 is now at the design stage, but I doubt if it will progress much over the weekend due to a lack of componts at home.

Keep going Kev, we're all counting on you ;)