Tach Mod

[1ofnone]

How do I do it?

Hi,
I've read in here about people's experiences with basic tach installation. I want to know how to connect the fuse to the red and white wires of the Jr Dragster Tach. I also need info on how to connect those 2 wires to the white wire in the low-beam connector.

Thanks

1

[Dandy Dan]

After all these years a tach install is still a black art it seems...there are quite a few ways to do it and it kinda depends on the tach you buy. You've got the same tach as Chanito though so he should be able to set you straight when he comes online. You might want to do a search because I think he's explained it at least once.

[hello]

Thanks alot ;D

[chanito]

;D The Junior Draggster is a great tach, is a racing tach so it can take a lot of abuse and is extremelly accurate, the down side is that the instructions that come with it are awful, i do not have my shop manual with me so i will edit this post tomorrow with the proper color wires.
Anyway here it goes, the tach comes with 4 wires, one is ground, other is the signal wire, the 3rd is power and the last is the light, i made the mistake of installing the power and light to the low beam circuit, but when i switched to hi beams my tach went to sleep . The reason for installing it to the light was because it has a separate fuse, but since then i have installed it to the power wire coming from the power relay.
You need to install your tach first, i installed it to the crossbar in the handle bar, i bought a batt terminal from an auto part and then just took the strap that suppose to hold the cable, bent it a little bit, and then using two 8mm bolts clamp it to the bar.

then i used some shink tubing i got from radio shack to hide the wires and route them into the batt box, once in there you need to cut the wire to size and attach an eyelet to the ground wire and bolt it to the batt negative post, then the signal wire needs to be connected to the test connector, which is the connector with the blue with a yellow stripe wire just hanging by the batt, get the power and the light wires, twist the ends together and connect them to a wire that has power with the ignition on, and you have now a very good tach that looks very similar to the factory speedo

[1ofnone]

Thank you very much ;D

Do you have any step by step photos you can post too?

Did you use a 2 amp fuse on both the red and white wires or just the red one like it says in the fabulous instructions?

Where and how are the red and white twisted wires connected to a wire that has power with the ignition on?

Thanks so much

1

[Dandy Dan]

There are two banks of wires near the battery. The wire you use for power when the ignition is on is the same wire you use to power a CDI so just go to Battlescooter.com to the tech section and look at the how-to and you'll see which wire they use. I believe it's the green one with a black stripe but I'm not sure which bank. Maybe just prick a hole in the insulation and touch the tach wires to see if it works before you completely strip and solder it together.

[1ofnone]

After installing the Kitaco CDI(North American), I could not get my Tach to engage until I revved up to 4000rpms where it drastically jumped from 0. It measured the rpms from 4k and up but that's it.
I connected the power and light wires to a 2 Amp inline fuse and then to the same place the CDI got it's power from. Ground to Neg post and the signal wire to what i assumed was the signal connector left over from the CDI install. Didn't work correctly. I gave up after trying to connect the signal wire to the ignition coil post, but to no avail.
The Tach's light and power turned on when I switched the key to the ON position. But the rest is a test of patience...

Help me

[Dandy Dan]

Okay so if I'm understanding you correctly, your power is working great. It turns on when you flick the key on and it lights up and everything. The only problem is with the signal wire...I'm not really sure where you have it hooked up now because it sounds like you tried the 'left over CDI signal connector' and the 'ignition coil post' but neither worked out.

Did you try tapping directly in to the ignition coil wire? The yellow/black wire that goes to the ignition coil should have a signal and that's what works for some tachs like my Veypor but the signal is a bit weak so the Veypor loses it a bit as it nears the redline and on cold days etc.

[1ofnone]

You are correct. ;D
Do you mean splicing and soldering the signal wire in to the ignition coil wire? If so, is it the stock wire to be tapped?
I'll try it and let you know.

[Dandy Dan]

Hmm....since you have the CDI, I'd say you'd want to slice/solder into the yellow/black CDI wire that goes to the coil. Your tach might be different but that's how mine hooks up. I know with my tach (Veypor VR2) there are 2 wires and one is a light wire that you can wire up to a tach signal source if you already have a tach or something and then the other wire is a heavier gauge wire that you can use to tap right into the ignition coil wire or pretty much anywhere. I'm not sure what the intent of your wire is so I can't say for sure that's it's safe to tap into the yellow ignition wire but that is a good source for a signal if you want to risk it.

[chanito]

1ofnone said:

You are correct. ;D
Do you mean splicing and soldering the signal wire in to the ignition coil wire? If so, is it the stock wire to be tapped?
I'll try it and let you know.

NOOOO! you need to tap into the cranksignal wire, is the "blue and yellow wire" by the batt box
::)that is the only wire you need for your tach signal

[1ofnone]

Even if the CDI connector plugs into that blue/yellow wire?

Thanks

[Dandy Dan]

chanito said:

NOOOO! you need to tap into the cranksignal wire, is the "blue and yellow wire" by the batt box
::)that is the only wire you need for your tach signal

The Veypor VR2 comes with 2 wire for the tach, one is a lighter wire that you can use if you already have a tach and you just splice into the signal wire going to that. In the case of the Ruckus this would be the blue/yellow wire under the battery box. The 2nd wire is heavier as is intended to splice into the wire to the ignition coil.

What I'm confused about is why does using the blue/yellow wire work for everyone with a normal tach but when a Veypor owner (Sanjuro and myself) try to tap in here the scooter dies? I stripped a little bit of this wire and when I touch the tach signal wire from the Veypor to it the scooter just coughs for a couple seconds and then dies.

[chanito]

1ofnone said:

Even if the CDI connector plugs into that blue/yellow wire?

Thanks

Yes just hook the CDI and the tach to the same connector ( i just solder them together and plug it in )

[chanito]

dandydan said:

chanito said:

NOOOO! you need to tap into the cranksignal wire, is the "blue and yellow wire" by the batt box
::)that is the only wire you need for your tach signal

The Veypor VR2 comes with 2 wire for the tach, one is a lighter wire that you can use if you already have a tach and you just splice into the signal wire going to that. In the case of the Ruckus this would be the blue/yellow wire under the battery box. The 2nd wire is heavier as is intended to splice into the wire to the ignition coil.

What I'm confused about is why does using the blue/yellow wire work for everyone with a normal tach but when a Veypor owner (Sanjuro and myself) try to tap in here the scooter dies? I stripped a little bit of this wire and when I touch the tach signal wire from the Veypor to it the scooter just coughs for a couple seconds and then dies.

That signal is from a wave generator in the flywheel, the ECM uses that signal for the ignition, I am not sure why but my guess is that the Vaypor uses a signal amplifier and some how ground that signal therefore killing the wave, with no wave the ECM can not control timing so your engine can not run, different tachs uses different way to count rpms, the autometer tach was design for a Briggs engine that uses a similar wave generator, so that is why it works so great on our engines, and since it uses the same signal as the ECM, the tach is super accurate ;D

[Dandy Dan]

Thanks for explaining that! Makes sense.

[1ofnone]

How sweet it is

I just installed my Tach and I couldn't be happier. I have to go out on a nice long ride to get a good indication of the power of the little beast.

Thanks for all your help guys.
mission accomplished

1

[chanito]

Congrats, and do not forget
and explain how did you do it ;D

[1ofnone]

The Autometer Jr Dragster Tach has 4 wires. White for the Tach's light, Red for the power, Black for the ground and Green for the signal.









I used the rubber from a bicycle tire tube to put between the crossbar and u-bolt clamp


Fitted u-bolt clamp after I filed the mount's holes


I used good ole electric tape to wind up the wiring


Final result


Idles (Shaky) at around 2k. Off the line it revs up to 5k in an instant. Red lines at 8k. On the stand I get up to 9k before letting it shake off and drive itself away.



;D

1

[chanito]

Looking great, the only change i would do is turn the bracket that hold the tach (the one with the u bolt) around so the tach sits lower and closer to the speedo level congrats