Cheap Tach Accuracy

[Bodaggit23]

So I successfully installed an el cheapo tach from Harbor Freight.

 

Basically I used the cheapie as an excuse to create a wire harness

for a nicer tach in the future.

 

I used the yellow wire from the right rear coil as suggested by coop

for the trigger and ran the other wires into a length of 3/8" split flex

tubing, under the tank, up to the triple trees where I'll be installing

a 4-5 pin plug. For now it's hard wired, but you get the idea.

 

The tach works "perfectly", smooth sweep and very responsive.

The yellow wire was an excellent choice, thanks coop!

 

My question is, does my bike idle at 400RPM? I thought I read

somewhere they idle around 1000ish. Or no?

 

The rev limiter is set around 6000RPM but on this tach, to me,

2000RPM is painful...I almost never push that hard before a shift..

 

I think it reads low...confirm?

 

https://www.youtube.com/watch?v=m4MMoKy6I3Y

[djh3]

Hard to tell. But I dont think your @ 1000 RPM either. It sounds to me closer to the 500 than 1000 RPM. I have yet to run mine up to the limiter either.

[XV1100SE]

Keep in mind that there is a waste spark on the bike. On the multi-meter I have I have to double the reading to get the proper RPM value.

 

I don't have a tach on my bike but if you are shifting at 2000rpm you are shifting way too low. Peak torque is at 3500rpm. You should shift between 3000 and 3500rpm. Rev limiter on 2nd Gen is at 6200rpm....think it is the same on yours.

 

http://www.bikez.com/motorcycles/yamaha_xvz_1300_royal_star_tour_classic_1997.php

[etcswjoe]

Try changing the number of cylinders selector to see if it will come closer to 1000 RPM.

[MiCarl]

It appears to be reading 1/2 the actual rpm.

 

I looked up the user manual for it. It's designed for a distributor type ignition and you set it for 4, 6 or 8 cylinders.

 

I assume you've got it set to 4 cylinder which means it expects the coil to fire twice per revolution (it counts the firing and divides by 2 to come up with the rpm). Problem is your coil fires once per revolution. When it divides by 2 it comes up with 1/2 the actual rpm.

 

I can envision a way to trick it by using some diodes and connecting it to two coils, causing it to see 2 sparks/revolution.

[brd7666]

Maybe you can buy the adapter. Here are the instructions for the Barons Tach. This is the one I used. I did not need an adapter.

 

http://www.cruisercustomizing.com/installguides/ba-7570-00.pdf

[gibvel]

Do you have a link to this tach on Harbor Freight? I searched the Harbor Freight site and can't seem to come up with it.

 

Edit:

Never mind. Go figure I search on the site, nothing I search on google, there it is!!

[PGunn]

You need to connect to 2 coils usually the 2 on the right side under the tank. If not you get 1/2 of your true reading.... Take from experience....

[XV1100SE]

...My question is, does my bike idle at 400RPM? I thought I read

somewhere they idle around 1000ish. Or no?

 

The rev limiter is set around 6000RPM but on this tach, to me,

2000RPM is painful...I almost never push that hard before a shift..

 

I think it reads low...confirm?

 

Per my earlier response.... if your tach is reading 1/2 the actual value, you are saying you are shifting at 2000rpm according to the tach? Then you are running the engine fine. That would be 4000rpm.

[Flyinfool]

Maybe you can buy the adapter. Here are the instructions for the Barons Tach. This is the one I used. I did not need an adapter.

 

http://www.cruisercustomizing.com/installguides/ba-7570-00.pdf

 

I am betting that the barons tach adapter is nothing more than 2 diodes and maybe a capacitor since it claims to also smooth needle bounce.

 

I would try it first with the 2 diodes.

 

Cyl 1 ----|>|---|

|--------Tach input

Cyl 2 ----|>|---|

 

OK its a lousy representation of a simple schematic......

[XV1100SE]

You need to connect to 2 coils usually the 2 on the right side under the tank. If not you get 1/2 of your true reading.... Take from experience....

 

Do you connect two different wires from the tach to two coils or does the same wire go to two coils? One wire across two coils - wouldn't this pass electricity between coils?

[etcswjoe]

Do you connect two different wires from the tach to two coils or does the same wire go to two coils? One wire across two coils - wouldn't this pass electricity between coils?

 

 

That's where Jeff's diodes come into play. DO Not short the two coils together!

[PGunn]

Do you connect two different wires from the tach to two coils or does the same wire go to two coils? One wire across two coils - wouldn't this pass electricity between coils?

 

First line the picture will show you what you need. I picked up the parts at Radio Shack.

http://www.venturerider.org/forum/showthread.php?t=29859&highlight=tach+install

I am still using the orginal parts I installed and no issues.

[XV1100SE]

J&P sells a single fire adapter for $34 - http://www.jpcycles.com/product/730-382

I'm sure it is cheaper to make your own but sometimes it is easier to just buy one off the shelf.

[Condor]

Same thing happened with the Cycle Pro tach I mounted on the '99. In my case I failed to throw the right dip switches on the back of the PC board. So I just 2x the reading until I need to get back in there for something else. Then I'll start experimenting....

[Bodaggit23]

Thank you all for your input!

 

......if you are shifting at 2000rpm you are shifting way too low. Peak torque is at 3500rpm. You should shift between 3000 and 3500rpm. Rev limiter on 2nd Gen is at 6200rpm....think it is the same on yours.

 

I agree, 2000rpm would be too soon to shift, which is why I questioned the accuracy.

You are correct, I have the manual for 1996-2001 and it states approx 6,000 r/min.

 

Try changing the number of cylinders selector to see if it will come closer to 1000 RPM.

 

That's the first thing I tried...

It is set on 4 cyl.

If I switch to 6 cyl. the RPM drops lower.

A switch to 8 cyl. drops the RPM yet again.

 

Per my earlier response.... if your tach is reading 1/2 the actual value, you are saying you are shifting at 2000rpm according to the tach? Then you are running the engine fine. That would be 4000rpm.

 

That makes sense...although to my ears, 2000rpm on my tach (4000rpm actual) seems

too high! lol I rarely push that hard.

 

First line the picture will show you what you need. I picked up the parts at Radio Shack.

http://www.venturerider.org/forum/showthread.php?t=29859&highlight=tach+install

I am still using the orginal parts I installed and no issues.

 

That is excellent! I saw that a couple weeks ago but wasn't sure what it meant...

Makes much more sense now! lol

 

I may try creating the little gizmo if I can find the parts, it seems simple enough.

 

Thank you all again for your most valuable input! And thank you for not flaming

my hose clamp mount!

[Bodaggit23]

I got the components, $3.20 later, all put together.

 

It may be a few days before I get it installed. I need

to look back and make sure which other coil wire I need.

 

Is it the front coil on the same side, or the other rear

coil, or does it matter?

 

***EDIT***

I found the post! Woohoo!

 

You need to connect to 2 coils usually the 2 on the right side under the tank. If not you get 1/2 of your true reading.... Take from experience....

 

That makes life much much easier! The front coils are WAY easier to get to.

Edited July 10, 2014 by Bodaggit23

[Bodaggit23]

I hooked up the "single fire adapter" to two coils and it reads perfectly now!

 

I used both rear coils (yellow and orange wires).

 

Thanks to everyone that read and commented on this, could not have done

it without the input from this site!

*clicks link to subscribe and become supporting member*

 

Edited July 12, 2014 by Bodaggit23