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Drag Specialties tach wiring help

12K views 26 replies 9 participants last post by  mark4of5 
#1 ·
I mounted the tach now it time to wire it up. It is a four wire tach and I also have a three wire converter. It says to connect red to a coil wire. Since there are two coils does it matter which coil. Is the converter needed for the 1800? Also where is a good place for getting a switched power source. I have the tank loose and the headlight opened up. :?

Thank you!
 
#2 ·
If you have a C model than there is a Yellow wire in the headlight bucket that is not connected to anything. This runs to the rear cylander and is for a tach.

PS. If you list the specs of your ride at the bottom of you signature, it sure helps us everyone out. Thanks :)
 
#3 ·
new problem

Thanks for the tip. The tach works but it is only indicating half of the engime RPM. It indicates a little under 3000 rpm when I hit the rev limiter. Any ideas? :?
 
#5 ·
You will need to run a wire from the front Coil also. I have just installed the same tach a couple of weeks ago. I am reading your post now. Tomorrow if you dont have it figured out I will grab my wire diagrams and help you out. Your missing a wire and then you will be all set. Let me know if you got it fixed or if you need some help. I can walk you through it. And a Search on here would be advised. There is all the information you need in here some where. Thats how I found what I needed. And you will learn a ton more on a lot of other subjects.

Strick
 
#6 ·
Strick said:
You will need to run a wire from the front Coil also. I have just installed the same tach a couple of weeks ago. I am reading your post now. Tomorrow if you dont have it figured out I will grab my wire diagrams and help you out. Your missing a wire and then you will be all set. Let me know if you got it fixed or if you need some help. I can walk you through it. And a Search on here would be advised. There is all the information you need in here some where. Thats how I found what I needed. And you will learn a ton more on a lot of other subjects.

Strick

Yep.....the "yellow" wire in the head light is to the back coil. You have to run another wire (supplied) to the front coil. I don't remember the color.
 
#7 ·
You will have to run your own wire there is not one supplied. And it depends on what wire diagram your going by. I used Big Mikes instructions. And he was good enought to forward them to me. I will look up the post he sent me and forward to this post tomorrow.
Strick
 
#9 ·
still need help

I have used the search feature on this board and called a local drag specialties dealer and haven't found the specific wiring diagram yet. So I would greatly appreciate the diagram. I like the tach and already have it mounted. It would be cool to get it to work if possible.

Thanks! :tools1:
 
#10 ·
Tach Drag Specialties Instructions PER.BIGLRY

I am not able to find a link to these instructions. So I am going to just sit and type them out . Here go's

You said you had it mounted already so I will skip that part. I took the tank bolt off under the seat and was able to slide the tank back enough that I had room to get to the coil. You will need a " two male spade connector" Hardware store has them. This you will hook to the front coil. Use the connection farthest to the outside. Inside connection you cant get to very easy. And you dont want to.Connection is coverd by a black plastic cover. And is at the rear of the coil.

Run the 4 black wire bundle from the Tach into headlight. I used a four wire "computach adapter" In my headlight shell. Came with the Tach. If you dont have one get one from Drag Specalties. All wireing can be done in the headlight this way.

1. Remove Seat, and fuel tank hold down bolt,slide tank back, it will go back just enough to expose front ignition coil. Left side KEY SIDE.

2. This is where your going to tap in with the two male spade connector to one female end.Also you will need one female spade connector for the wire you will hook here and run into the headlight shell. I used black wire to match the rest of the wires. About 14" you can shorten later.Your done here. Put tank and seat back on. Everything from here is done in the headlight.

3. Combine red wire with blue wire from tach with male spade connector that you picked up with the other connectors. Then find the brown wire on speedometer wire connector. If you go to the speedometer side of plug connector the wire is brown this is your 12V key switched on, hot wire. I used a quick splice, like for trailer lights to car with spade female reciever. Just like the one that came with your PCIII ( if you have a PCIII) Put a dab a silicone on the splice, Plug together.

4. Hook green Tach wire to Pink wire of the Tach adapter. I used plug connectors but soldier will work fine with shrink tape.

5. Black wire from tach is ground. I used the green wire from the turn signals are hooked to as I dont run a ground for my running lights you can tap into here if you want.

6. Find stock yellow wire with female end there will be nothing hooked to it, inside the headlight shell. This wire is a direct connection to the rear ignition coil. Hook this yellow wire to the white adapter wire.

7. Now remember the wire you ran from the front ignition coil. Black is what I used . This wire is spliced to the black wire on the tach adapter, Plugs or soldier will workwell.

8. This will all fit in the headlight shell, just arrange on the top so it dose not interfer with the light adjustment knobs. Install headligh and ring and thats that.

Thats what I have. I just got done with the install so if you have any questions fire away. I will be around tonight and I will check from time to time. GOOD LUCK
STRICK
 
#11 ·
still monkeying with it

Emailed drag specialties. I may have the wrong converter as it is a three wire and I may need a four wire. I'm waiting on their input. I appreciate all the help!
 
#25 ·
I think I highjacked your thread.....
I most humbly apologize.... 8)
 
#13 ·
I just went through this mess with DS what a PIA, the tech was of no help and couldn't snswer my questions. I tried two different adapters neither would work,most I could do was hook up to one coil and get 1/2 the rpms. Also same from tach lead in the head light (on a c model).
Baron custom acc. was very helpful , they guaranty their's to work on my 03 1800c.
I'm waiting for the tach and adapter to show up at my local independent shop, should be this coming week !

https://www.baronscustom.com/catalog/display/1942/index.html

https://www.baronscustom.com/catalog/display/243/index.html
 
#14 ·
>>>We’re you able to make it work? I have the 2.4 DS tach with an adapter and it is still not working when both coils are connected.
If I drop one on the coil wire the tach reads half the rpm.

>>>>>>I just went through this mess with DS what a PIA, the tech was of no help and couldn't snswer my questions. I tried two different adapters neither would work,most I could do was hook up to one coil and get 1/2 the rpms. Also same from tach lead in the head light (on a c model).
Baron custom acc. was very helpful , they guaranty their's to work on my 03 1800c.
I'm waiting for the tach and adapter to show up at my local independent shop, should be this coming week !

The camshaft position sensor GRAY wire has turned out to be the best tach signal source for aftermarket tachs.
 

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#15 ·
Thanks Hans, I tried the cam wire trick as well and got double the rpms.....
I did see the pdf attachment before , what was said at the beginning of it made a lot of sense by decreasing the resistor strength.
But after two very frustrating emails with the DS tech I decided they don't want or need my $$ so they got their tach back...
As I said Baron was very helpful so they got my $$
I did also order this tach as well, its a 3" marine one and will work on Alt./outboards/ and coils, also very adjustable so the pdf info will be helpful.
Thank you for it :)
https://www.westmarine.com/buy/sierra--heavy-duty-series-tachometer-6000-rpm-o-b-4-stroke-gas-engines--205544?recordNum=9
 
#16 · (Edited)
Alt./outboards/ and coils

Signal from the alternator, outboards or IGN coils.

Seastarsolutions.com could be the supplier of the Sierra tach.
http://www.seastarsolutions.com/support-2/faqs-2/instrumentation/

How do I adjust the selector switch on my tachometer?

See the Tachometer application guide in technical support. On the rear of the tachometer the black rotary selector switch is placed in the 4C, 6C, or 8C position respective of how many cylinders there are in your Stern Drive or Inboard engine.

Place the selector switch in positions 2P, 3P, 4P, 5P, or 6P for Outboard engines listed in the Technical Support, Tachometer Selection, (Outboard Engine with Alternator.)
Universal Tachometers with this type of labeling of the selector switch are capable of operating on both stern drive/inboards (4 cycle) and outboard engines.
Certain Chrysler and most pre 1993 Force outboards require a special tachometer that will operate correctly for the 20 pole alternator on those engines.

2P, 3P, 4P, 5P, 6P seems to represent the poles in the alternator.

My 1300 stator/alternator has 6 poles per phase. I suspect the 1800 has the same number.

Ask many questions because you are trying something that has not been previously done AFAIK.

wholesalemarine.com has the tach for $71.45
SKU: SIE-82288P

I also noticed the marine suppliers had VDO tachs and I remembered something about VDO on VTX.
https://www.vtxoa.com/forums/6-vtx-1800-tech-board/228864-vdo-tach-no-needle-bounce.html
 
#17 ·
Yes- the VDO tach is what came with the Rivco setup for the 1800 C. I love it.
 
#18 ·
Marine Tachometer on a 03 1800c

Hans thank you,
I did talk with Sierra last week and they gave me a website to go to so I could read/study the installation instructions and I did that, now the smart thing would have been to save that to my favorites (key phrase "would have been").
The poles are the number of magnets on the rotor (looked at some used ones on ebay to get a count), looked like 18 which corresponds with your count of 6 per phase.
But in order to go that route you must tap into the ac side of the alt. before the diodes convert ac to dc , which means peeling that side of the engine apart to solder in a lead and bring that to the outside unless the alt. has a ac tap (don't think it does).
Then set the alt. switch to highest pole count which is only 16 and use the tach. adjustment screw to hopefully get it on the money....
Kinda complex but might be possible, maybe.....
My first choice would be the cam position sense wire (I believe it shows 4 pulses) then set the tachs number of cyl's. to 4 and it should read correct , again hopefully....:confused:
Second choice would be DIY tach adapter using the instructions in your earlier post but I think the #cyl. switch comes into play on that one as well.
The price you saw is not what I'm getting it for , I can get it at cost (my friend owns the marina :thumbup:) which makes the experiment
much more worth trying (its the sisu in me).
What is AFAIK ? I couldn't figure that one out and its killing me to know :grin2:

ranger4u - thanks as well I did read up on your posts about the VDO's as well they are a good quality gauge and hold up well, still need the adapter thou (think you said its no longer in production)....
I just wanted to have a nice tach of good quality that reads correct and lasts (reason for the experiment).
I will keep you guys posted on progress.
Thanks :bowdown:

This for bouncy tach needles:
 

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#21 ·
Hans thank you,
I did talk with Sierra last week and they gave me a website to go to so I could read/study the installation instructions and I did that, now the smart thing would have been to save that to my favorites (key phrase "would have been").
The poles are the number of magnets on the rotor (looked at some used ones on ebay to get a count), looked like 18 which corresponds with your count of 6 per phase.
But in order to go that route you must tap into the ac side of the alt. before the diodes convert ac to dc , which means peeling that side of the engine apart to solder in a lead and bring that to the outside unless the alt. has a ac tap (don't think it does).
Then set the alt. switch to highest pole count which is only 16 and use the tach. adjustment screw to hopefully get it on the money....
Kinda complex but might be possible, maybe.....
My first choice would be the cam position sense wire (I believe it shows 4 pulses) then set the tachs number of cyl's. to 4 and it should read correct , again hopefully....:confused:
Second choice would be DIY tach adapter using the instructions in your earlier post but I think the #cyl. switch comes into play on that one as well.
The price you saw is not what I'm getting it for , I can get it at cost (my friend owns the marina :thumbup:) which makes the experiment
much more worth trying (its the sisu in me).
What is AFAIK ? I couldn't figure that one out and its killing me to know :grin2:

ranger4u - thanks as well I did read up on your posts about the VDO's as well they are a good quality gauge and hold up well, still need the adapter thou (think you said its no longer in production)....
I just wanted to have a nice tach of good quality that reads correct and lasts (reason for the experiment).
I will keep you guys posted on progress.
Thanks :bowdown:

This for bouncy tach needles:
I don't have the Ph. # anymore, but you might look up Rivco Products, and ask to talk with an electronics tech, I know I talked with someone in California when I was having installation problems. But it's been 2 more years now since then. They were able to find me the correct black module to make it work, maybe lightning can strike twice and they find one for you! Good luck.
 
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#19 ·
AFAIK= As far as I know

I do not like the dynatek diagram.

Minus side of coil goes to ECM.
ECM pulses one coil normally, tied together it would pulse both coils. A 10k resistor to combine the two pulses is the right way.
 
#20 ·
Haus is correct.....


the driver circuit for the coil.. is not designed to drive 2 coils
( double the current ) aka a killed ECU..


so be warned.
my opinion.
 
#27 · (Edited)
I did try the Baron Custom Acc. tach and adapter today results were very poor, it worked but had heavy needle bounce in all rpms it was virtually unreadable.
I tried the tach without the adapter and taking the signal from the cam pos. sensor and that was better by far but still twitchy.
I called Baron and they said that" VTX's have a very noisy ignition system and that it works on some 1800 c's and not others very hit or miss".
Question is what happened to their "Guarantied to work" claim?????
I did talk with VDO as well , no more black box to make their tach work.....
Stewart Warner has tachs that should work off the alt. (up to 18 poles) and possibly cam pos. sensor and using just one coil signal as the tach has a user settable pulse per/rev.
I will have my marine tach on sunday so I'll give that a try then.
Equus does have a small tach that will work as well but its not water proof (my old one isn't ether and that one has taken a few baths).
So we will see....
 
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