shift light/tach combo

[RaWarrior]

Was flipping through the new Summit catalog and noticed this in it. It's a little shift light pod that also has a tach readout in the middle.

That one is a touch over 2" in diameter

Found a similar one here that's also a little cheaper. You can also get them in black or silver cases, with blue, green, or red lights/displays. This one is a little smaller, says 1 5/8" diameter. It also looks to have a pre-curved mounting bracket so it's be easy to stick to the speedo.

Seems like a good way to get a tach display up on the handlebars where it belongs without having to spend a load of money on aftermarket clusters and losing your stock speedo.

I'm thinking about ordering the Glowshift one. Theres a couple youtube videos and the response seems to be pretty fast and the shift light is quite bright.

Anyone know if the "tach adapter" is needed on the Vmax? As far as I can tell my current Raptor shift light just taps into the stock tach's signal wire, any reason this would be different? Switching from coil packs to COPs did not affect the function of either the shift light or the stock tach.

 

[misiek93]

The first shift light you have listed is for 4,6, or 8 cyl. If I remember correctly in order to work on a V-max it needs to work on 2 cyl.

 

[CaptainKyle]

Nice find I like the gloshift one

 

[gamorg02]

The first shift light you have listed is for 4,6, or 8 cyl. If I remember correctly in order to work on a V-max it needs to work on 2 cyl.

yea good point, i don't think you would need anything except something ready for 2 cylinders.

 

[one2dmax]

I am not sure if it will work or not? We used an MSD version and others like that with ok results but I think it went down to 1 cyl too. Anything in the summit catalog I can sell though it wouldn't be much cheaper then they have it for (but you'd be supporting me lol!)

Sean

 

[deekjx]

The first shift light you have listed is for 4,6, or 8 cyl. If I remember correctly in order to work on a V-max it needs to work on 2 cyl.

I'm curious about this. When I look at a wiring diagram for the VMax, I notice that the tach is tracking the pulses of the spark for one of the 4 cylinders. Given that we have a 4 stroke engine it should spark once every two revolutions. What does the number of cylinders have to do with counting the revolutions? Are some systems setup to count the spark of all the cylinders rather than one?

There is an article about the lack of accuracy with OEM Tachs in super street bike (SSB) magazine but they didn't go into any real detail. They just dyno'ed some bikes to get an accurate reading and compared that to the installed tach so they can note the difference.

 

[RaWarrior]

The Vmax uses a waste-fire ignition, meaning it fires at EVERY TDC. So it fires at the top of the compression, and at the top of the exhaust.

So there's 1 spark every revolution. Compared to a non-waste fire, this would make the engine appear to be spinning twice as fast, so to compensate, the tach would need to "expect" 2 sparks per revolution.

Automotive systems usually read the total sparks, not sparks per cylinder, which is why gauges have settings for 4,6,8 cyl. The more cylinders the higher the denominator(if you had a correct tach on a 4cyl, and moved the setting to 8cyl, it would read exactly 50% of actual RPM).

So the Vmax is a 4cyl, but it produces the total sparks for a "normal" 8 cyl for any given RPM. But the Vmax tach only reads one coil, not all four, so divide total sparks by four,

OK....I see where the "2 cyl" setting comes from.

Though it lists "a tach adapter may be needed for multi-coil systems", so I assume that means in cases where the signal is from one(of multiple) coils instead of the one sole coil distributing to all cylinders. So such a device readily exists?

 

[m-cman]

Are they weatherproof though?

 

[KJShover]

I wouldn't call them weatherproof being they're designed for the inside of a car. But I think it would be possible to seal them up good enough to take a mild rain, but not the direct deluge of a hose.

Autometer makes one that is good from 1-12 cyls.
http://www.autometer.com/cat_accessoriesdetail.aspx?vid=200

Otherwise, there is always the option of wiring it up like the guys that are running the Autometer tachs.

 

[deekjx]

The Vmax uses a waste-fire ignition, meaning it fires at EVERY TDC. So it fires at the top of the compression, and at the top of the exhaust.

So there's 1 spark every revolution. Compared to a non-waste fire, this would make the engine appear to be spinning twice as fast, so to compensate, the tach would need to "expect" 2 sparks per revolution.

Automotive systems usually read the total sparks, not sparks per cylinder, which is why gauges have settings for 4,6,8 cyl. The more cylinders the higher the denominator(if you had a correct tach on a 4cyl, and moved the setting to 8cyl, it would read exactly 50% of actual RPM).

So the Vmax is a 4cyl, but it produces the total sparks for a "normal" 8 cyl for any given RPM. But the Vmax tach only reads one coil, not all four, so divide total sparks by four,

OK....I see where the "2 cyl" setting comes from.

Though it lists "a tach adapter may be needed for multi-coil systems", so I assume that means in cases where the signal is from one(of multiple) coils instead of the one sole coil distributing to all cylinders. So such a device readily exists?

Awesome. So traditional installation would require a 2 cyl setting. People with T-Boost can easily wire it up a 4 cylinder tach by connecting to the T-Boost lead that's tracking 2 cylinders instead of the tach lead that's tracking one or if you don't have T-Boost, you will need you manually run a line from another coil with in line diodes (to prevent back feeding) to get this to work.

That and some sealant to waterproof these should allow them to work.

Sent from my Galaxy Nexus using Tapatalk 2

 

[bazwell]

Awesome. So traditional installation would require a 2 cyl setting. People with T-Boost can easily wire it up a 4 cylinder tach by connecting to the T-Boost lead that's tracking 2 cylinders instead of the tach lead that's tracking one or if you don't have T-Boost, you will need you manually run a line from another coil with in line diodes (to prevent back feeding) to get this to work.

That and some sealant to waterproof these should allow them to work.

Sent from my Galaxy Nexus using Tapatalk 2

I'm not sure, but Dingy has posted about the early model and late model ignition being different in respect to waste spark, no waste spark.

However, a 4 cylinder car with a single coil has the coil firing 2 times per revolution. A vmax coil with waste spark fires once every revolution. So, what deekjx says there ^ is 100 correct.

In that case you need 2 diodes, and wire the tacho to 2 coils to get a config the same as 4 cylinder. You probably won't need the 3rd wire and resistor like T-boost uses. Quite simple to do if this guage is what you want.

 

[RaWarrior]

Awesome. So traditional installation would require a 2 cyl setting. People with T-Boost can easily wire it up a 4 cylinder tach by connecting to the T-Boost lead that's tracking 2 cylinders instead of the tach lead that's tracking one or if you don't have T-Boost, you will need you manually run a line from another coil with in line diodes (to prevent back feeding) to get this to work.


That and some sealant to waterproof these should allow them to work.

Sent from my Galaxy Nexus using Tapatalk 2

So I do have t-boost...came on the bike, never use it, but it does work

There's a schematic on vmaxoutlaw for a homemade t-boost setup, though I'm not sure how the 3-position switch versions are wired. Never really looked that carefully. Anybody know what wire would need to be tapped into? Rigging up the diode thing doesn't seem that hard, but if that's already there, might as well use it.

Then again, there's the Autometer unit that just has this compatibility right out of the box. It's considerably more expensive though and looks to be pretty chunky. Wonder if there's space for it under the flyscreen.... 2" diameter x 5" length. Have to take some measurements when I get home and see if there's room for it before I pop $140 on one.

 

[gamorg02]

ryan, have you looked at the ecliptech lights? same price as you're talking here and i've loved mind. fully programable and i have it set up to 'act' like a tach.

 

[deekjx]

There's a schematic on vmaxoutlaw for a homemade t-boost setup, though I'm not sure how the 3-position switch versions are wired. Never really looked that carefully. Anybody know what wire would need to be tapped into? Rigging up the diode thing doesn't seem that hard, but if that's already there, might as well use it.

For people with T-Boost always on, they can just run a wire from the connection going to the V-Boost Controller. That is down stream of the diodes and has both ignition pulse coils going through it. This will provide the signalling for your 4 cylinder setting. Very simple and easy.

If yours is on a switch, you can't use that point because your RPM gauge will vary based on when T-Boost is on or off due to the switch blocking the impulses from one of the coils. It may save you the effort of having to run a wire to the front of the bike on the new vmax models. Basically you will still have to use diodes like the guy that doesn't have T-Boost. Depending on the T-Boost wiring, they may run one coil up to the switch or possibly both coils in the case of a 3 way switch. The goal would be to bridge on to the wire for the coil that is not used by the Tach. It seems that the coil used by the tach changes from the older year to the newer year gen 1 vmaxes. Prior to 1990 they used Coil 2 but starting in 1990 they used Coil 3. You can see this in the wiring diagram on Sean's website "Morley's Muscle". Unfortunately the coils are not numbered on this diagram but comparing the two different years, you will see that a different coil and wire color is used. So the T-Boost wire on the pre-90's bike would be coming from coil 4 and on a 90+ bike will come from coil 1. Attaching a wire to this T-Boost wire, and running it through a diode will give you your first half. You would then have to take your tach lead and attach a diode to it and that will give you the second half. Connect those two halves together and run it to the RPM gauge that is for 4 cylinder settings and you are done.

Hopefully someone can confirm/correct this but basically if your T-Boost is always on, using a 4 cylinder gauge is easy stuff. Other than that, you'd need to use diodes and wires to make something that would work with those gauges. It wouldn't be hard to make. If the adapter cost more than 5 bucks, I wouldn't buy it. I would just hit up radio shack.

 

[RaWarrior]

I found a manual for the "3 position" style t-boost from google. The little box intercepts the connector to the stock controller. Two wires go from the switch to the box, the third is a lead to the left-rear coil(90-up) or the left front(85-89).

So what I assume must happen is that at the "3k" switch, it completes the circuit from the added-in coil pulse to the diode box, and it now outputs a 2x tach signal (in one of the wires) to the stock controller). At 6k the switch acts as a loop, making circuit between the two wires from the box and excluding the second coil wire, giving 1-pulse function. Center/off makes no circuit, so the controller just sees 0 rpm all the time.

So I don't think having t-boost would help, unless I left it at 3k all the time, and tapped into the signal wire between the box and the stock controller. There's no wire that always has a "2x" pulse signal, so the diode rig would be needed. I could re-use the "third wire" to the t-boost switch since it's already hooked up to the correct coil for doubling, and the stock tach wire, do the double diode thing, and send that signal to the 4 cyl style tach.

The Glowshift one is $55 shipped on ebay, the Autometer one I found for $140 shipped....pretty hefty price difference, though the glowshift one is a bit smaller, has a fixed mount, and from youtube videos looks like the response is a bit slower. The autometer has a swivel mount and rotates/tilts in any direction.

Once I can get home and take some measurements I'll see where there's room for it. I'd rather keep the flyscreen but that definitely limits space around the speedo, and my handlebars are already crowded with an oil psi and water temp gauge.

 

[misiek93]

I found a manual for the "3 position" style t-boost from google. The little box intercepts the connector to the stock controller. Two wires go from the switch to the box, the third is a lead to the left-rear coil(90-up) or the left front(85-89).

So what I assume must happen is that at the "3k" switch, it completes the circuit from the added-in coil pulse to the diode box, and it now outputs a 2x tach signal (in one of the wires) to the stock controller). At 6k the switch acts as a loop, making circuit between the two wires from the box and excluding the second coil wire, giving 1-pulse function. Center/off makes no circuit, so the controller just sees 0 rpm all the time.

So I don't think having t-boost would help, unless I left it at 3k all the time, and tapped into the signal wire between the box and the stock controller. There's no wire that always has a "2x" pulse signal, so the diode rig would be needed. I could re-use the "third wire" to the t-boost switch since it's already hooked up to the correct coil for doubling, and the stock tach wire, do the double diode thing, and send that signal to the 4 cyl style tach.

The Glowshift one is $55 shipped on ebay, the Autometer one I found for $140 shipped....pretty hefty price difference, though the glowshift one is a bit smaller, has a fixed mount, and from youtube videos looks like the response is a bit slower. The autometer has a swivel mount and rotates/tilts in any direction.

Once I can get home and take some measurements I'll see where there's room for it. I'd rather keep the flyscreen but that definitely limits space around the speedo, and my handlebars are already crowded with an oil psi and water temp gauge.

A member asked a while ago for a copy of T-boos instructions. Here's a link to it
http://www.vmaxforum.net/showthread.php?t=22239

this is exactly what came with the T-boost with the 3 position switch.