[zmint]

Originally Posted by ilangop

Could you please post a schematic of how the tacho was wired in the HH Splendor.

It was connected the same, as your posted schematic shows :
brown = positive = to ignition which has battery connection or direct to +ive terminal
black yellow= negative = to battery -ive terminal
blue = pulse = connects to ignition coil INPUT ( NOT OUT PUT)

Originally Posted by ilangop

Hope your electronics lab is equipped with a multimeter.

I have(HAD) two of them. One analogue and the other digital for more accurate readings.

Originally Posted by ilangop

Set it to AC 750 V range and measure the voltage at the place where you hooked up the tacho signalling point in both cases.

You well know, the HT coil input (in both cases) where I connect the tacho have two points, the one connected to body frame is obviously earth and the other I assume is positive.

When I checked the voltage at these points :
With -
1) Analogue MM : The 1000, 250 & 50 (AC V) range did not move the needle. The 20 V AC range had the armature moved a bit. (Little on idle and upto 2 V with the throttle pulled)

2) Digital MM :
a) HH S. Splendor : .8 V at idle and gradually to 2.4 V with 1/2 throttle, on MM 200V range (750V range did not show results)

b) LML : The reading was not stable to quote, It was not aperant at both the ranges (200V and 750 V) Sometime it showed 2.4 and next moment the MM went off scale (1). You know the scooter(2 stroke) idle is not as smooth, as compaired to a 4 Stroke. So I tried a bit acceleration, but again the reading was not stable.

Next, I tried connected the tacho with the second method you suggested. Wound 4-5 turns of a unshilded wire around the wire going to the spark plug and connected the signal wire to it, but a big NO.

Originally Posted by ilangop

As well check if both tachos still work after you experimented on the NV.

We are thinking alike, because that is the first thing try to make sure, every time I disconnect the tacho from the mighty NV. I successfully tested my Tachos on both HH & Activa (Still to try with Kinetic Nova, I know it will work)

Eventually the Tacho will have to befriend my Vespa. (I won't let go off, so easily)

It is worth mentioning here, that a couple of years earlier, I made the agency guy connect a digital tacho to my beauty. The tacho worked with charm. It was a old Japanese, non-contact type tacho(Opama Puls Tacho meter). I googled it up, and found a Indian company who imports it but the price was exorbitant (around 4 to 5 K)

I think, either
a) something is wrong with the frequency we are getting from the coil input.
b) maybe my ignition timing is bad (Don't know If it has a role to play
c) The coil is malfunctioning.
d) I made a deep study of the spark plugs working principals, and I figured out that mine (Mico W 8 DC) is without a registor, which is a must, in order that the spark-plugs electronic noise do not interfear with nearby electronic machines. (but then I wonder, the japanses tacho worked so close to the spark plug)

Anyhow what every the reason may be, finally I come the reason I wrote, 'I have (Had) two multimeter'

The Digital one has gone Digitally MAD, after Its interaction with the NV. I hoped, the fuse inside the meter would blow-off of as a safety measure to excess voltage, but it did not. As a result, I am only able to use the poor thing, to check the continuity with a beep, nothing else. As DIY guy, I will try my luck on rectifying the problem. My stethoscope to the electronic world as gone nuts, but the show must go on, I will acquire another one, soon.


From all this, what do you figure out so far.

Thanks for reading this long post.

Zmint

[ilangop]

Hi Zmint,
I guess that the voltage output by the CDI in vespa is comparitively lower than that in HH. Hope you have changed Ct & Rt. With the new values of the Ct & Rt try to recalculate the required R3, R4, & C3 following the same steps as in the design example shown in 5th page of the IC data sheet. Before modifying the components in the circuit board, ensure that the Ct is fully charged & discharged in ever cycle with the existing R & C values at various locations.
-Ilango

[zmint]

Originally Posted by ilangop

-
We ll discuss tuning the tacho for 3 & 4 cylinders later. That might require a 12-0-12 transformer for having 100 Hz.

I think, it is the right time to discuss it now. Please proceed.
Will a 3-0-3, 6-0-6 or 9-0-9 do the job, because they can also provide 100 Hz, I suppose ?

Thanks

Zmint

[ilangop]

Originally Posted by zmint

Will a 3-0-3, 6-0-6 or 9-0-9 do the job, because they can also provide 100 Hz, I suppose ?
Zmint

Yes they can be used, the data sheet says that the min i/p voltage is 2V. Since the system voltage is 12-14V I prefer a transformer of about the same voltage range. Otherwise there is no harm in using it for bench testing. While calibrating the tacho refer to the graph that shows the relation between the needle deflection angle and the error. Choose whether to use 50 Hz or 100 Hz based on the possible needle angles where you get the minimum error.

[thedreamcatcher]

Nice job done. Isn't it tough maintaining the car though?

[ghpk]

can this be done to a Santro Xing ?

[tanwaramit]

Originally Posted by ghpk

can this be done to a Santro Xing ?

+1 to this question, Also, Can this be done in a simpler way on Santro Xing ?

[ilangop]

Originally Posted by tanwaramit

+1 to this question, Also, Can this be done in a simpler way on Santro Xing ?

Originally Posted by ghpk

can this be done to a Santro Xing ?

Hi guys,
Actually I tried to hook this setup with a Zen Estilo of a friend's. But things dint work at all. No idea what I was missing. Have to go through more literature on this.

[Karthik1100]

@ilangop, can i see the pictures how did you connect the tacho in your car?

[ilangop]

Karthik,
Sorry,dont have a picture. Does this help?
http://www.team-bhp.com/forum/techni...ml#post1240665
What are you up to? Trying a DIY or planning for a Tacho for your Padmini?
-Ilango

[Karthik1100]

Originally Posted by ilangop

Karthik,
Sorry,dont have a picture. Does this help?
http://www.team-bhp.com/forum/techni...ml#post1240665
What are you up to? Trying a DIY or planning for a Tacho for your Padmini?
-Ilango

ya mainly planning for a tacho on my padmini, i saw one, if i can directly fix on my car, i'll go with it, if not DIY. would like to know the installing procedure.

[boohooper]

Real neat job! I was wondering why you did not remove the Clock from dash and fit the RPM meter there. You could have relocated the Clock to where the RPM now resides. Or you could do another DIY to fix a Digital Clock where the Ashtray sits on your dash.

[funkykar]

You are one hell of a DIY artist. Hats off to you mate. I am so much tempted to try this for my 118 NE. I will first see if I can find a enthusiast who can help me with this as my knowledge of electronics is 0 or in the negative range. I will seek help from you if needed.

From now on, you either make 2 copies of whatever DIY you do for the 118 NE or relocate to Bangalore magaa

[cadaver_prad]

Your a genius mate. . Im a DIY guy myself but this idea never crossed my mind. Any idea how to make one for a diesel vehicle?

[ilangop]

Originally Posted by cadaver_prad

Any idea how to make one for a diesel vehicle?

I guess, you want it for your MM540. Is it equipped with a Turbo by any chance? Else you need to play around with the alternator to tap the engine speeed signal.