Add a Tachometer

[Water Warrior 2]

Originally Posted by trykemike

Hey guys now that you have the tach what cruising rpm sounds comfortable to you ?

I like 5000-5500 rpm. I have ran 20 km @ 6250-6500 without problems.

My top speed occurrs @ 8000rpm in 5th ( 80 mph ) 125-130 k/ph

Most days I can reach 7500 rpm in 5th 120 k/hr ( 75 mph ) max.

On longer rides 20 km + I just keep below 6000 rpm and the engine runs fine.

Interesting info. With all that has been said and done I would think the 250's have a sweet spot at about 6000 rpm in most cases. Thanks.

[jonathan180iq]

I get the most pull between 5500 - 6500, for what it's worth.

Anyone ever dyno-ed one of these things?

[Sarris]

Installed my tach today. I used the one from the Power Outlet Store listed in the first thread. It arrived in just 2 days. (WOW) I installed it in about 30 minutes. I used the horn hot wire for both the 12v+ connection and for the light connection.

It all seems to works as it should. Mine has just a little "bounce" at idle and I wondered if everyone elses does that as well.

:??:

Kudos to the Quimrider for his excellent How To.

[jonathan180iq]

Does it look like an electrical bounce or the bounce that you would expect to get from differing idle readings?

I have no bounce. I get a little wobble, with idle, when sitting at a redlight for a long time.

PS:
I also had to cut and rewire my coil wire to get a little extra slack. In doing so, I upgraded to a slightly thicker wire. This may have something to do with it.

[Sarris]

It's just a little wobble. More like a slightly unsteady idle. I've double checked all my connections and all is OK. The more I think about it, I'm fairly sure its a combination of an unsteady idle and a cheap tach. I compared it to the one in my Scion XB and it does the same thing, so I'm pretty sure it's OK.

I'll keep an eye on it. Thanks for the response.

:2tup:

[Quimrider]

yea a little bounce is near idle is what you get with this tach. Mine did this less when I switched from using the coil +12V to the horn +12V.

[5th_bike]

Installed mine today, it is the one from Dennis Kirk (1-7/8") part # 40-7646 for $69.95 plus $6.95 shipping.

I mounted it at the bolt that holds the right turn signal assembly. The tachometer dial is almost straight with only a degree or two rotation, hardly noticeable.

The zip tie that holds wires and front break hose together, needed loosening in order to mount it. No need to cut it, just lift the little lip that sticks out of the 'cube' and it will loosen. It can be tightened in place again after mounting.
Also I needed to temporarily undo the break hose from its holder at the left fork, about halfway down, to loosen it and to make space for mounting the tach. Now the brake hose sits snug around the tach.

See pictures below. Sorry for the crummy picture quality, it was getting dark and I didn't use the flash.

Thank you QuimRider for the inspiration :2tup:

Thank you TrykeMike for suggesting to power it from the horn +12V, it works like a charm and the only wobble at low revs is due to actual rev fluctuations. :rawk:

And thank you JonathanIQ180 for finding that nice little tach at Dennis Kirk.

[5th_bike]

OK I wanted to post some better pictures, here they are:

Right after starting it, with the choke on:




Overview, how it looks like on the bike:




Close-up from front (and, sorry for not cleaning the dried bug guts from the signal light stem, and for having the brake hose, gas cables and the wires obstruct the view):




And then, here is my very first cinematographic accomplishment on youtube, showing the tach in operation:



I'm glad it works but it IS an extra distraction....

[ppronti]

Hey Guys (and Gals):

I know none of you has ever heard from me before, but I have spent about 10 hours (probably even more) studying the electrical schematics of this bike from the Service Manual. Anyway, if you would allow me to offer my “two cent’s” worth as far as this tachometer modification goes, my suggestion represents how a tachometer would be OEM “Engineered” into the bike. Please do note that the following suggested wiring is accompanied with explanations that any of you can verify on any version/revision of the schematics of this bike, and (therefore) is a [*nearly*] universal fit. [This statement is qualified because, according to the service manual revision I have (which covers through model year ’07), there is a significantly different schematic for “Country Code 19”, a country for which my manual version does not identify – as you will read, that version of the bike has no running lights other than at the rear brake-lamp, speedometer illumination, and a position light indicator – I will elaborate on how to wire a tach on that version where appropriate too! ]

First, let me start with this suggestion… go to your local “pull-your-own-part” automotive recycling yard (or similar) and search for a 4 pole (wire) wiring connector (a joint that has BOTH sides of the connector with about 2 inches (5cm) of wiring on each side) and use it for your installation - one side to the wiring harness, and the other to the tach lead. (And if you want to pay attention to even FURTHER detail, note that the bike main harness has all male sides of the connectors branching from it… so you can emulate this degree of “OEM detail” and hard wire the male side of the connector to the harness! ) The purpose in putting a connector into this installation is for the case that if you ever need to service the bike to a significant degree, you will have an OEM appearing joint that you can easily disconnect (rather than dismounting the tach from the handlebars and having to un-route the tach lead from the frame of the bike). Pay attention you are keeping the wiring properly continuous through each side of the connector.

And one other preemptive suggestion – you should be connecting all wires into the wire harness just at the front of the driver’s seat, right at (“above”) the carburetor because this is the most forward point where all the wires you need are at in the main harness [with exception to the “Country Code 19” bike]. The harness routes from the fuse block forward. There is a connector at the carb that branches off the main harness that feeds/connects (on all models) the Engine Stop Switch, Starter Button, Front Break Light Switch, and if bike is so equipped on other models, the Lighting Switch. Two of your connecting wires terminate in this branching connector, while the other two remain routing forward in the main harness.

Tachometer Red Lead – connect to Orange Wire with Blue Tracer on bike

Tachometer Blue Lead – connect to Gray on bike (note to all – the tach blue wire can be connected Orange Wire with Blue Tracer on any bike BUT know that if you have a lighting switch on your bike, the tach light will not turn off with the rest of the running lights/instrumentation light – further description follows) [Specifically on Country Code 19 bikes, connect this lead to the Orange Wire with Blue Tracer wire – the “running light” circuit on your bike, as mentioned before, powers only your speedometer light, your brake-lamp “running light”, and a position light on the front of the bike, and this Orange/Blue tracer wire is routed more directly to these three lamps]

Reason for both above connections (please reference the wiring schematics with the following description) – When Ignition Switch is in the “ON” position, solid Orange (fused only by the Main Fuse before the ignition switch) wire supplies power to fuse 3, fuse 4, and fuse 5 at fuse block. Fuse 5 powers the Orange Wire with Blue Tracer, which is the “Ignition On” circuit (also reference instructions for the tach) for the lights/instrumentation, and it also is the power feed for running lighting circuit (Gray wiring) by one of two means. One way is through a “Lighting Switch” (on bike versions that have such a switch, which controls running lights and the headlight separately), or, on bikes without a lighting switch, jumper wires replacing the switch that allow always-on running lights and always-on headlights, [including “Country Code 19,” even though the wiring is routed further forward on the bike)]. (And, for everyone’s information, if you trace the wiring even further, you will find the Gray Running Lighting circuit [Orange/Blue Tracer for “Country Code 19”] further feeds the Brake-Running-Light and Position Light (if so equipped) circuit (brown wiring) when the ignition switch is in the On (Run) position.

In other words, this is because some countries allow the operator to control the running lighting and headlights on the bike, but in other nations (like in the United States) it is law that a motorbike have its’ running lights and a headlight on at all times that the bike is running. So in this case the lighting switch is eliminated and is replaced by “jumper” wires to complete the connections permanently. And there are two jumpers because the running lights are a separate circuit from the headlight, but both are otherwise controlled by the 3 position Lighting Switch (1. all lights off, 2. running lights on (circuit1), 3. running lights (circuit 1) and headlight (circuit 2) on).

So, if you notice, the factory fuse description of fuse 5 “tail light” is really not accurate. This one fuse actually powers all running lights (on truly ALL models).

So in summary for these two connections, when the ignition is “on”, since there is always MAIN FUSE PROTECTED power on the Orange/Blue wire (“Ignition On” circuit), this is where the Tachometer Red lead connects. And, since further “downstream” Gray wiring powers all running lights on the vehicle, the Tachometer Blue lead should connect to the Gray – so that it’s light turns off/on with other running/instrument lights on the bike if there is, in fact, a switch. (So, again, on any bike that does not have the “Lighting switch,” an alternative is that you may connect both red and blue Tachometer leads to either the Orange/Blue wire or the Gray.)

Tachometer Black Lead – connected to Black Wire with White Tracer on bike

Reason – Black Wire with White Tracer is Universal Ground (Including ground for ALL lighting on the bike – all shown traced directly to battery negative terminal)

Tachometer Green Lead – connected to White negative terminal of coil

Reason – Green Lead has to connect to negative terminal of coil (as otherwise stated in other previous postings)
NOTE: there are 2 white-wire circuits in total on this bike – one for the negative coil and the other for the headlight “low beam” circuit. Depending on where in the wiring harness you are tapping, you may need to pay attention to which white wire you are connecting to! (easy to tell – if you turn the Ignition Switch to the “On” position (and Lighting Switch “On,” if appropriate) and the dimmer switch to the “Lo” position, and a 12V test/light show’s power on whatever white wire you are probing, you have the WRONG wire).


Here is a summary, if you will:
Tach Red – Orange/Blue Tracer (Ignition “On” circuit that powers Instruments/Lights)
Tach Blue – Gray (Running lights circuit powered by above circuit)
Tach Black – Black/White Tracer (Universal Ground)
Tach Green – White connected to Coil Negative (Igniter spark “signal” to Ignition Coil)


Anyway, I hope this helps and maybe helps/improves everyone’s tachometer installations! (I guarantee there will be no horn-tone variance issues with this wiring!)

Paul Pronti

P.S. Notes:

In response to Quimrider’s submission about how much current the tach draws (Aug 15, 2007):
The tach’s “Ignition on” circuit draw’s .06 A.
The tach’s Illumination “Lamp On” circuit draw’s .12 A.
Total current required for BCS# 33-3910 tachometer is approximately .2 A (not sure if BCS is the manufacturer, but that is what the number is on the box)

In response to trykemike’s submission about voltage drop when pressing his horn (Aug 22, 2007):
You will not see a voltage deflection with what you have described. Voltage is constant from a battery (for the most part – unless you are drawing more Ah than the battery can provide, in which case yer gonna kill the battery). However, you may see some current draw fluctuations, if you know how to measure that (note that it is different than measuring voltage – you measure voltage drop across a load, current is measured in-line in the circuit – you have to disconnect whatever circuit it is you want to know how much current is there and complete the circuit through the ammeter – feel free to ask further questions if you don’t understand what I mean).

[Easy Rider]

Originally Posted by ppronti

Hey Guys (and Gals):

In response to trykemike’s submission about voltage drop when pressing his horn (Aug 22, 2007):
You will not see a voltage deflection with what you have described. Voltage is constant from a battery ........

Hey, welcome. Good post, for anyone who is into that much detail. I think there are a couple here that ARE.

Gotta comment on the above statement though. Voltage is relatively constant AT the battery, assuming we aren't talking large loads, like the starter running but............the voltage may NOT be constant at the other end of a wire.....after it goes through connectors, fuses, wires, switches, etc. as all of those things have a little resistance that often causes a small voltage drop. It is usually not significant though.