How about a cheap tach?

[webbt2]

I think a good number of us want tach's for our little thumpers.

Maybe on this forum or another I got a little info on changing the pins on a chip in an aftermarket tachometer to make it work for a single (instead of 4, 6, 8 ).

I pick up a cheap tach (harbor freight $20) but after getting it apart, I think it is different then the one used in the info I found.

I would really like to make this work and am willing to sacrifice this tach on a good hunch.

My hunches aren't so great with computer chips, anyone interested or got some good idea's/info?

[dsrt4]

Just Get a Tiny Tach.

http://www.norwall.com/product_info....erm=TT226NR-2C

[webbt2]

Yeah that would be way to easy plus I'm a sucker for analog gauges. I'd like to get this figured out just to do it :wink:

[forchetto]

That Tiny Tach won't be any good for motorcycle use. The update is every 2.5 seconds. It may be OK to set the idle but that's about it. It was designed for stationary, constant revs, engine use.

I have tried several methods of adapting normal tachos to CDI equipped engines without success. Very frustrating.

[bones33]

Just wanted to bump this.

Anyone find a good way to modify a 4/6/8 cyl tach? I guess there may be a way to change resistors in a tach to suit 1cyl engines. The nice looking Harbor Fright tachs are 19.99 on sale now and, being the cheapskate I am, would like to mod it to fit.

Here is what I've found for modifying so far: http://www.electronics-lab.com/forum...?topic=7424.14

[Weldangrind]

I've had the very same thought. Since the site you linked gives us a basic impedance value, a variable resistor could be used to dial in the correct number.

If you have an old tune-up tach, you could connect it to get a baseline rpm (if you don't have one, you could likely find one at a thrift store or garage sale). You could then trim the HF tach until it reads the same rpm. Once the value is established, you could either solidify the variable resistor with some RTV, or you could solder in a resistor(s) to get the same value.

The only part I'm unsure of is whether it would take a linear or non-linear taper potentiometer. Anyone?

[TurboT]

Originally Posted by Weldangrind

The only part I'm unsure of is whether it would take a linear or non-linear taper potentiometer. Anyone?

A what?? 8O

That's beyond my realm of concious thinking.

[MICRider]

Lol, same here! Think I would just buy a Vapor and save myself the skullcramps

[mizke]

its not exactly on the cheap side, but considering its made for dirt bikes and enduro bikes, street bikes, etc....

http://www.rockymountainatvmc.com/pr...lVehParts=true

[cheesy]

Originally Posted by bones33

Just wanted to bump this.

Anyone find a good way to modify a 4/6/8 cyl tach? I guess there may be a way to change resistors in a tach to suit 1cyl engines. The nice looking Harbor Fright tachs are 19.99 on sale now and, being the cheapskate I am, would like to mod it to fit.

Here is what I've found for modifying so far: http://www.electronics-lab.com/forum...?topic=7424.14

Might be worth futzing with. I have fun frying electronics. I do have a spare 1 cyl digital tach that still may end up being zip tied to the Hi Bird, tho.

[acydrx]

http://www.motosportsparts.com/s.nl/it.A/id.14061/.f

It is for the SunL / MDL Powersports SLD-200GY. It may work for what you need, it is the whole cluster, unfortunately. Directional and high-beam indicators included. That is one of the only China bikes I've seen with a tachometer as a standard item. Not quite the Harbor Freight $20 tach, but I would imagine there is much less tinkering required. Also, it is a ton cheaper than the more awesome Trail Tech computers.

EDIT: As a side note, I believe the speedometer is Km/h.

[bones33]

The stock SunL unit is out of stock, the Vapor unit has lots of other functionality that may make the unit worth the price tho. The plan is to have the air fuel ratio gauge next to the tach to monitor changes due to temp/altitude and use a Dial-a-Jet to adjust accordingly. Hey, 200cc only does so much!

I think I'm a gonna try the Harbor Fright unit and cramp my brain to see if I can solve the puzzle. Will post progress.

[mizke]

um every afr guage ive ever installed is spliced into the o2 sensor... so unless your bike has a o2 sensor and is efi.. i dont see how its going to work

[SpudRider]

Originally Posted by bones33

...I think I'm a gonna try the Harbor Fright unit and cramp my brain to see if I can solve the puzzle. Will post progress.

Please do keep us updated.

Spud

[Weldangrind]

Originally Posted by mizke

um every afr guage ive ever installed is spliced into the o2 sensor... so unless your bike has a o2 sensor and is efi.. i dont see how its going to work

Yes, you need an O2 sensor, no, you don't need EFI. It's easy to weld in a sensor bung, and a wide band sensor provides a resisted voltage that can be interpreted as O2 content. You're shooting for one Lambda or 14.7:1 A/F.

You can use the O2 sensor with an A/F guage, but a voltmeter works.