Add a Tachometer
 

https://i.postimg.cc/bZLsdsZV/tachgroup2.jpg
http://powersportsoutletstore.com/product/33-3910

[strike:3eovo2fv]About 57 dollars after shipping. [/strike:3eovo2fv] This is not a fancy tach. just a plain and simple 8K RPM tach.

Update 08/17/10: Powersportsoutletstore.com has entered the dustbin of history.

I found what appears to be the same tach at BKrider for $39.99 + $8 and change shipping.


Additional parts needed for install
- Zip ties as needed.

Tools required:
- Soldering iron and solder.
- Socket set preferribly with extensions.

Overview:
This is a quick installation guide for the above tachometer. Installation should take about 1/2 hour. All wiring is done directly to the ignition coil for the simplest wiring. If you want to get creative there are other way you can do it. There are two wires that attache to the ignition coil with female blade connectors. The one on the right side of the bike is the negative and the one on the left is the + 12V. We will be soldering to these female blade connectors and using the mounting bolt of the ignition coil as a grounding point.

Step 1 Mounting:
https://i.postimg.cc/zbyLs8Xt/T1.jpghttps://i.postimg.cc/HcFJHRrp/T2.jpg
- Use the conviently located bolt shown in the picture for attaching the tach with the included bracket.
- Remove the nut and washer
- Slide tach over bolt
- Put washer and nut back on.
- If you don't like that the tach is at an angle you could easily make a custom bracket so it is at the same angle as the spedometer.

Step 2 Wiring:
https://i.postimg.cc/k2yt8Tpc/T3.jpghttps://i.postimg.cc/gwSXtndL/T4.jpg
- This wiring diagram was the only instructions that came with the tach.
- These are the wires we have to work with.
looking at the diagram we will be connecting the green wire to the negative terminal on the coil. Since our lights come on when the key is switched to "on" we might as well have the light for the tach and the power for the tach switch on with the key as well. It just convienently happens that the +12V for the coil is also switched on when the key is in the "on" position. So we will connect the red and blue wire to the +12V terminal on the coil. The last remaining wire is the black ground wire. Also convienently there is a mounting bolt inbetween the coil terminals. We will connect the black wire to this bolt for a ground.
- Remove the gas tank (see service manual)
- Route wire from tach to the front of the ignition coil.
- Leaving a couple extra inches cut the excess lenght of wire off.
- Trim back the black outer shell a couple inches to expose individuals colored wires inside. BE CAREFUL NOT to accidentally cut the individual wires when trimming back the outer shell!

https://i.postimg.cc/gLRx0sh3/T5.jpg
- Disconnect the two wires with the female blade connectors from the coil and slide back rubber insulators. It may be easier to slide back the rubber insulators first to disconnect the female blade connectors.
- The wire that was connected to the left side coil terminal is red, This is the +12V. The white wire connected to the right side coil terminal is white and the negative wire.

(Note: this is on my 2000 GZ250. Other years may have different wire colors. To be sure, use a multimeter to see which one of these supplies +12V with the key switched to "on".)

EDIT NOTE: As suggested by another member I have switched to pulling the +12V from the horn. Switch the key to the on position and use a multimeter to see which of the two horn wires has +12V with a multimeter. Either way will work, but pulling +12V from the horn circuit is probably a better idea. Using the horn circuit may help with idle and idling if you have a low battery. Also my needle "bounced" less at 1000 to 1500 RPM after moving the power source to the horn circuit.

- Slide the red and blue wires from the tach up thru the rubber insulator on the red coil wire.
- Solder these wires to the back part of the female blade connector.
- Repeat the above 2 steps soldering the green wire from the tach to the white wire with the female blade connector.
When done soldering it should look like this:
https://i.postimg.cc/18SqfkJX/T6.jpg
- Connect the remaining black wire to the coil's mounting bolt inbetween the terminals for the ground wire.
- Slide the rubber insulators back over the female blade connectors.
- Reconnect the blade connectors to their respective terminals on the coil.
- Finally secure the wire in place with zip ties.
This is what it should like.
https://i.postimg.cc/rdFR9S6L/T7.jpg
Put your gas tank back on and go for a ride :cool:
Remember to be safe and keep your eyes on the road. Don't get too distracted by your new tach.

Awesome Stuff. Good work. It looks pretty solid.
When you get a chance, can you throw us a few tach/speed readings?

What's the RPM in 5th at 60mph and so on?

Take care,
Jonathan

I'll have to check when I can find some wide open traffic free road. I can tell you that at 75mph it's a tick over 7500 rpm. Probably between 7550 and 7600 RPM. I still have the stock 15t front sprocket. I've been trying to get a 16t front sprocket from bike bandit since June. They can't seem to get any. It idles at about 1000 RPM. The tach is real bouncy at 1000 RPM but completely smooths out by 2000 RPM. Who knows if the gauge is accurate but the numbers seem to be reasonable.

I went for a ride at lunch and watched my RPM's at 30, 40, 50, and 60 MPH in 5th gear. It looks like I could use my tach as a spedometer! The only one I know for sure is that at 40MPH it was exactly 4000 RPM I had to watch the road and couldn't tell exactly but it looks like 3K RPM = 30MPH, 4K = 40, 5K = 50, 6K = 60 MPH. It doesn't help that my tach is mounted at a slight angle so getting a precise reading is difficult.

tach mounting adjustment
 

Will the tach spin in the mount? Does it have a bolt on the bottom to loosen it from the mount or is the housing and mount one piece?

Thanks

nope. if you look at this picture, it shows the back. there are 2 studs coming out of the tach that go thru two holes on the mounting bracket. Since the mounting bracket is just a flat piece of metal with holes you could easily make your own bracket and put it at any angle you want.
https://i.postimg.cc/bZLsdsZV/tachgroup2.jpg

quimrider is there any issue when adding the tach re: power draw against the coil ?

will this addition affect reliability ?

I don't know how much current the tach draws, but I can't imagine it would be very much at all. The light bulb in the tach probably draws more current than the tach itself. If it were to draw too much current, you'd blow a fuse before you would see ignition problems. Well... you'd see ignition problems when you blew a fuse! :lol: I've gone thru several tanks of gas with no problems. If you're still concerned about current draw you could simply not hook up the blue wire (light bulb) or you could wire the power for the tach and light bulb in with the headlight circuit. Although I think this would be a waste of time.

In my VW Beetle the tach, ignition coil, fuel shutoff solenoid, and the electric choke are all powered from the same circuit. I haven't looked at the schematic for the GZ250 electrical system but I'd imagine there is more on the ignition coil circuit than just the coil.

Then again maybe not. Remember that this bike will stop firing with a weak battery BEFORE it gets too weak to turn the engine over. :roll:

Well again, maybe not. Having the tach powered off of the positive side of the coil might explain why the reading is "jumpy" at low revs. :cry:

Interesting, I've never heard that. A good thing to know when I have a weak battery and it won't start.

I'll test this theory by temporarily running a fused wire from the battery for tach power.

I found out the hard way.......twice before I got a new battery! :cry:

It has since been confirmed by others.

Them little suckers are expensive.......~ $85. :tdown:

Quim, very good write up. Looks great and very easy to understand.

Good Job!

[quote=Easy Rider]I found out the hard way.......twice before I got a new battery! :cry:

It has since been confirmed by others.

Them little suckers are expensive.......~ $85. :tdown:[/quote:19od4bto]

Jumper cables. I got mine. Used them once already. :)

Tiny little things.

adding a tach
 

hey quimrider thanks again for the howto. I installed the tach last night. I made a modification to the original instructions.

1 - I took + 12 v from the orange horn wire after checking it with a volt meter it gave + 12 v when the key is switched on

2 - the connectors for the coil were encased in hard plastic which I did not want to break and the leads were very short so I threaded the wires through the ends of the connectors and folded them over then inserted the connector back onto the blade on the coil.

3 - I turned on the key the tach flexed the tach light came on I started the bike it reved to 4000 then quit after 30 secs. It would not start after several attempts.

4 - I took off the tank again and noticed a small black hose behind the main fuel line. I connected it to the nipple on the carb.
( vacuum line )

5 - after remounting the tank the bike fired up then I took it for a spin.

6 - the tach is smooth even at 1000 rpm

Re: adding a tach
 

Good job! :tup:

I wonder what the tach needle will do when you activate the horn ??? :roll:

adding a tach
 

hey easyrider I tested the horn wire with a voltmeter and pressed the horn button no needle deflection was evident. I have tested the tach with the horn no problem.

Re: adding a tach
 

Check. I wouldn't expect to see a deflection when set to measure DC. Just for curiosity, try setting your meter for AC and hit the button once. Them cheap horns tend to make "waves" on the feed line.
Anyhow, good that it works without interference.

Hey quimrider since adding the tach I have on several occasions been able to pull 7500-7600 rpm with indicated speed of 125 kph. I usually run out of road space to get past this speed. Have you ever reached 8000 rpm in 5 th gear ?

before switching to the 16t front sprocket I could hit 80mph which = 8000RPM going down hill or with a decent tail wind. I've never been able to get past this. If you browse over to the 16t sprocket thread, I don't remember who but someone put up a nice graph of rpm vs speed with both the 15 and 16t sprocket. Since adding the 16t sprocket, the fasted I could go was 79mph. I don't remember what RPM's that was but the graph should give you an idea. If you're considering the 16t front sprocket. It makes riding in town better since it spreads the gears out a bit and on the highway the engine doesn't sound so angry. The only down side is that is may have knocked a couple mph off my top speed as it takes longer to get up to 75mph and very difficult if not impossible to go faster. Although 4th is usable up to about 65 for going up hill. and if you don't like it, you're only out about 18 bucks and another 20 minutes to switch back to the old sprocket.

What RPM does the engine redline at?

Good question. I've never been able to find a definitive answer. I would guess 8000 or maybe 8500. My tach only goes up to 8000 but I have inadvertently over revved a couple of times to 9500-10000 estimated. and thankfully my engine is still in one piece.

Great writeup! I just installed the same tachometer this weekend and it's great being able to actually see what RPM the engine is running at. Everything went smoothly. My biggest fear was that the tank would be a pain to take off but it came off quite easily. I think I spent the most time trying to contort my fingers so I could get the nut back on the bolt after putting on the tach.

If I get adventurous, I might try bending the mounting bracket a little bit so that the tach angles in towards the rider like the speedo.

I'm installing mine tomorrow. How about some more photos from everyone?

The one that I purchased is a smaller model than the one lister here. I got from Dennis Kirk for $70.
We'll see if the install in the same. It should be pretty straight forward.

By the way, the service manual says the redline is 8,000 rpm.

No pictures, but a few suggestions. I would have some shrink tubing and some crimp lugs available to do the install.

For the ground wire, I used a round lug and attached it to the bolt on the center of the coil.

For the negative coil attachment, my blade connector had shrink wrap insulation which I had to cut off in order to solder the green wire. I then used new shrink-tubing to insulate it again.

I tied the power and illumination wires together and ran it back to the battery where I found a line that had switched +12v.

Finshed around11:30 pm.
It was only a 30 minute job but I also took time to teach a buddy of mine how to ride today.

I couldn't embed the video so here is the link:

http://www.youtube.com/watch?v=sG6C8hgr_cE

Only revved to 5k in the video since it was so late.
I'm glad I got this little thing.

Looks nice! Where did you end up tapping the power/illumination from?

I ran a line back to the rear running light. It's wired under the tank.

This is probably not an ideal place for everyone. But, I didn't feel like uninstalling my fairing wiring the light up and then reinstalling everything.


http://www.postimage.org/aVEwiTA.jpg
This is a 1 7/8" tach from Drag Specialties. (maybe specialists)
It's very nice. The chrome and black face match the OEM suzuki speedometer very nicely. The needle spools up with no deflection and it's operation is very smooth.

It's pulling juice from the horn wire, as suggested by others but I went with a simple ground to the frame. I installed wire-ends to the ground wire and bolted and mounted it onto and extisting bolt.

For the coil connection, I didn't have enough space so I cut the white Suzuki wire and extended it just a bit and mounted both the Suzuki white wire and the tach's coil wire to a new female blade connecter and slid the new assembly on the negative coil blade.

As with all of my wiring, it's a little ugly at the moment. When I have more time and I'm not distracted, I'll go back and clean them up and put weather-proof slides over the connections.

I'll post my installed pics as well:


http://www.postimage.org/gxKyoa9.jpg


http://www.postimage.org/PqieX90.jpg

tachometer
 

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.

I shift between 5.5 and 6k.

In 5th, I cruise around 4800-5500.
Twisting through backroads, I stayed in 4th around 6k rpm for a couple of miles.

Re: tachometer
 

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.

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

Anyone ever dyno-ed one of these things?

The Tach
 

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.

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.

Tach
 

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:

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.

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. :tup:

http://www.postimage.org/Pq1I8UHi.jpg

http://www.postimage.org/aV1wtcei.jpg
http://www.postimage.org/aV1wuj4i.jpg

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

Right after starting it, with the choke on:

http://www.postimage.org/gx2RYOH0.jpg


Overview, how it looks like on the bike:

http://www.postimage.org/gx2RYRb9.jpg


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):

http://www.postimage.org/gx2RZ7E9.jpg


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

http://www.youtube.com/watch?v=tEiJ-RFkKiU

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

Re: Add a Tachometer
 

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).

Re: Add a Tachometer
 

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.