SuzukiSavage.com - 5 wire tach install?

JutMan Junior Member Offline SuzukiSavage.com Rocks! Posts: 96 Poconos Gender:	Re: 5 wire tach install? Reply #15 - 10/19/15 at 09:08:23 I believe that the tech here is for a 2 cylinder bike so the waste spark will keep it true to RPM.
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Dave

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Re: 5 wire tach install?
Reply #16 - 10/19/15 at 09:53:10

I am not sure why the "spark count" has become so confusing.

The Savage and all motorcycles that use the crankshaft to activate a sensor will have a spark every revolution. This allows the engine to be run without a distributor or making the spark sensor use a camshaft driven sensor. On 4 cycle motorcycles one of the sparks will occur in the space between the intake/exhaust stroke and do nothing, the other spark will occur during the space between the compression/power stroke and the spark ignites the fuel. (If it is a 2 stroke bike both sparks will ignite a fuel mixture as every stroke of the piston produces an explosion).

Nothing really changes on 2 cylinder bikes - only on a bike with a 360 degree crankshaft can the same sensor and coil be used to power both pistons (the pistons fire 360 degrees apart and both pistons rise and fall together). On bikes with 180 or 270 degree cranks will either be be multiple sensors and coils, and each coil will again see 1 spark per revolution, and one will be wasted......or it will have a crank sensor that can located TDC on the crank and a computer to send the appropriate spark to a correct cylinder at the correct time (modern fuel injected bike....these are the kind of systems a Power Commander can be attached to).

On motorcycles that have the points or spark sensor mounted on the camshaft - there will be only one spark per each two revolutions of the crankshaft.

On engines with distributors and a single coil.....the number of sparks per revolution is obtained by taking the number of cylinders on a 2 cycle engine - or by dividing by 2 for a 4 cycle engine.

All you really have to know is to set your tach to "1 spark per revolution" for the Savage....and most other engines that don't use a distributor.

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KNOCKDOLIAN

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Re: 5 wire tach install?
Reply #17 - 10/19/15 at 11:07:16

Dave wrote on 10/19/15 at 09:53:10:

I am not sure why the "spark count" has become so confusing.

On motorcycles that have the points or spark sensor mounted on the camshaft - there will be only one spark per each two revolutions of the crankshaft.

That's the point I was making. The rev counter says universal. So unless you can set it for 1 or 2 sparks per revolution its not for all motorcycles is it ?

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Re: 5 wire tach install?
Reply #18 - 10/19/15 at 12:47:49

KNOCKDOLIAN wrote on 10/19/15 at 11:07:16:

Dave wrote on 10/19/15 at 09:53:10:

I am not sure why the "spark count" has become so confusing.

On motorcycles that have the points or spark sensor mounted on the camshaft - there will be only one spark per each two revolutions of the crankshaft.

That's the point I was making. The rev counter says universal. So unless you can set it for 1 or 2 sparks per revolution its not for all motorcycles is it ?

Where are you getting 2 sparks per revolution?

For almost every bike the coil will fire once per revolution if the trigger is on the crankshaft, and once every two revolutions if the trigger is on the crankshaft. Most multi cylinder bikes will have a separate coil for each cylinder.....so you are only going to connect the tach to one of the coils.

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KNOCKDOLIAN

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Re: 5 wire tach install?
Reply #19 - 10/19/15 at 13:29:03

Yep your right. Im not explaining myself. If a rev counter is designed for a bike that sparks once every two revs ie cam trigger and you put it on a crank triggered bike. one spark every rev it will read twice the speed ? The point I was making was that the rev counter is universal ?
That's it.
I use a strobe light with tacko on to check my tick over. because its designed to flash every two revs it reads twice the reading when on the bike
I know what I mean !!

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thumperclone Serious Thumper Alliance Member Offline PGR rider riding with respect Posts: 6059 Grand Junction Colorado Gender:	Re: 5 wire tach install? Reply #20 - 10/19/15 at 14:30:03 our bikes have a "wasted" spark 1 rev 1 spark, 1 cycle (4 strokes) 2 sparks = 2 rev
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Re: 5 wire tach install?
Reply #21 - 06/25/17 at 16:21:09

Rylee wrote on 04/18/15 at 22:43:32:

Did some more searching and finally figured it out. Tapped the light wires into the vacant horn power. Fed the coil wires up thru the tunnel and got the connected. Grounded everything on an unused factory bolt location left over from the bobber conversion. Everything is all buttoned up and wires heat shrunk and tucked away.

May not seem very useful where they are mounted but I wanted a clean triple tree and nothing above the bars. Surprisingly they are both in my extended field of view. To be honest I rarely even look at the speedo unless I see the fuzz and feel I'm going to fast. The tach was more for idle speed and to get an idea of what RPMs I'm at while cruising in specific gears. All I all I'm super happy.

25 bucks for both off eBay. Got them in 2 days and on e I figured out which wire was which took about 30 minutes to install. Took a test run to heat it up and see where my idle speed was and I was sitting at about 1400 RPMs which didn't feel bad without knowledge of the exact rpm. Now I know where it's sitting. Ran the gears out to up to 4500 to see what that felt like and realized when I thought I was pushing each gear I actually had quite a bit to go.

Ok, I have a similar Tach that I bought off ebay. I'm not super mechanical but I have pulled of the tank and everything. Problem is that I still don't understand how to wire the 5 wire tach.

I have a test light that I clamped to a neg on the bike and when I touch either of the posts on the coil it stays on which I thought would be off and then should flash when I push the starter.

I guess I need the dummies guide version of what to hook the wires to because I hear a lot about hooking up to the neg or pos side of the coil but I'm either not doing it correctly or not understanding.

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Re: 5 wire tach install?
Reply #22 - 06/25/17 at 16:46:37

The part I'm not understanding is mostly the coil part. I have wired lights and stuff before so I understand the pos neg leads for power. If I understand correctly, there are basically 2 pos wires, 2 neg woes, and then signal which goes somewhere. Maybe my test lamp test was done incorrectly (maybe the place I was attaching to for signal was correct but it's supposed to receive power)??? Any help would be great because I would like to put this back together and ride soon

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justin_o_guy2

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Re: 5 wire tach install?
Reply #23 - 06/26/17 at 09:26:09

Ran the gears out to up to 4500 to see what that felt like and realized when I thought I was pushing each gear I actually had quite a bit to go.

I'm guessing you've been shifting when you feel the torque fall off. That's a good shift point for fun and MPG and keeping your engine happy. The sound of my engine changes once it gets into the higher RPM. I don't really dig it.. I can't hear that once I hit fourth, but the first three gears, once it's a bit past the good acceleration it starts sounding like there is some kinda valve related racket.
Long life, performance and economy aren't found up around red line. And drag at speed keeps the engine from getting there in higher gear.

My take on it, and Gurus may tell me I'm wrong, so, I'll be following.

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