Home made gear indicator for the YZF750 (and other models)

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ThomVis
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Home made gear indicator for the YZF750 (and other models)

Postby ThomVis » Fri Dec 07, 2012 4:26 am

There's 12 pages of discussion, pictures and sorts about this on the Dutch YZF750 forum, and after some questions from other members here it is time to do a crude intersite copy-paste action.
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The original how-to on the Dutch forum comes from the Dutch FZR forum, where the indicator was placed on a FZR600. And since there are parts used from the Thunderace, the gear indicator can be placed as well.

There are generally 3 different versions of gear indicators out there:
- The commercial tach/speed driven one
- The homemade "analog" one
- The homemade "digital" one

The downside to the commercial one is you need to tune it in, and when you pull in the clutch, the unit cannot calculate the right gear and displays nothing or even the wrong gear. The homemade ones connect directly to the shift cam assembly, so they always indicate the right gear.

I'm describing the "analog" homemade version, I don't have the schematics to the "digital" one (picture), which uses an IC instead of diodes.

Wiring it to the bike
Regarding the connection to the shift cam assembly, you need (to make) the right cover plate (Neutral switch assembly):
Image

The YZF750 from '94 does not have all the connections on the cover plate. If yours doesn't either, you have three options. 1) Quit, 2) Get one that has, 3) Make it.
Option 1: Buy the commercial one and be happy with it, they're not bad.
Option 2: The Thunderace seems to have a plate with all the connections in place (left in the picture), and it fits the YZF750. Partno for this should be 4FM-82540-01-00, NEUTRAL SWITCH ASS. Remember, the partno for the YZF750 for all years shows up as 1AE-82540-00-00, but the later models have more connections than the early ones (right one in the picture). Partnumbers and amount of connections are not confirmed yet, order at your own risk.
Option 3: Look for the marks where the shift cam assembly touches the cover, predrill a small hole and press a hot nail through it. Laughing? Here's the picture:
Image
He pressed the heads flush with the cover inside, cut the nails to size on the outside and soldered the leads to it. Keeps the oil inside and makes a perfect electrical connection to the outside. He mentioned it was a fiddly job and he'll never do it again, but that's not meant as a discouragement. (oh, and the dots to represent the gear numbers are wrong)

This is where the cover goes (the shift cam assembly is in the middle of the picture):
Image
Some replace them without removing the water pump, I had no such luck.

Electrics
Now we have the connections to the gears in place, it's time for the electrics part of it. There are three main parts to the device, 1) Shift cam assembly cover connection, 2) Diode-block, 3) Display.
Image
Bad quality schematic, and I plan to redraw it on some rainy day, but when you understand the workings of a diode, you'll grasp the concept of the workings of this gear indicator. The resistors are there to keep the LEDs in the display from burning through, you'll need one for each LED.
How you attach the switched 12 volt feed is up to you, as long as the display gets 12V.

Components used:
33 diodes 1N4007, 162272-06
01 display SA36-11, 158780-06
07 resistors 1Kohm 0.25W (0207), 403253-06
01 printboard SU527629, 530809-89

The dashed numbers are the partnumbers at http://www.conrad.nl, there are pictures to give you an idea of the parts.

Here's one of my builds:
ImageImage
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ImageImage

Other guys have build different versions where the display is remote from the diode-block. One build the diode-block and display into the dials-assembly, others placed the diode-block near the ignition coils with a cable to the display he placed in the indicator section.
The cable I used was a CAT-6 ethernet network cable with solid cores (easier to solder). The guy who made the schematic used DIN-9 serial connectors to connect the diode-block-box to the "sensor" and remote display.

Display placement ideas
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Intelligence is alcohol soluble.

antidot
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Re: Home made gear indicator for the YZF750 (and other model

Postby antidot » Fri Dec 07, 2012 10:29 am

Great info. I've built mine similarly, instead of running hot nails through the "neutral indicator switch" I actually drilled fine holes and threaded them. I used very small brass screws, and just like you soldered wires from CAT5 cable ;) However, in the dash I put 6 LEDs in a row and one single resistor. Simple and works. Having actual numbers is fancier, thanks for the post. :good
YZF750RJ

davemfox2
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Re: Home made gear indicator for the YZF750 (and other model

Postby davemfox2 » Fri Dec 07, 2012 5:43 pm

Awesome post; I've been wondering how I was going to do that but now you've given me all the answers :thumbup:


Mods: Any chance of making this a sticky so that it doesn't get lost?

Dave
1993 YZF 750 SP with Yoshimura half system

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sickle44
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Re: Home made gear indicator for the YZF750 (and other model

Postby sickle44 » Sun Dec 09, 2012 7:30 pm

Thomvis,

Can you please if you have time redraw the schematic for the electrics. I'm very handy with soldering iron and I'm PC board competent, but I just don't read the actual drawings very well, unless it's for a speaker crossover. So; if you could 'xplain it to me/us like I was a two year old, that'd be golden my friend. 'Course, whenever you have the time, thanks very much, and Merry Christmas.
Michael
Yes Yes I know, I said, I'm building a project YZF1070, K. Well you mix two kids a WCB appeal, bringing a BMW 850i up to snuff & then some, mix in a little depression and .......

K, Yeah, I know excuses are just like a,holes; everyone's got one
I will be starting some day??.

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Re: Home made gear indicator for the YZF750 (and other model

Postby ThomVis » Mon Dec 10, 2012 2:18 pm

sickle44 wrote:Thomvis,

Can you please if you have time redraw the schematic for the electrics.


Image

And about letting an amount of LEDs burn according to the gear your in, looks cool, but here I have a device telling me the gear, instead of me having to count the bulbs. Maybe it takes getting used to, but I personally like it like this.

You could also leave the d connection out of the circuit when you're in neutral, gives you and "n". Personal preference.
Intelligence is alcohol soluble.

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sickle44
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Re: Home made gear indicator for the YZF750 (and other model

Postby sickle44 » Mon Dec 10, 2012 2:32 pm

Ahhhhh, Yes,

Now I understand, now that I can actually see what's going one. Might try and put a couple more segments in to the Led Array so I can get a nice capital N for neutral, that'd be cool I reckon. The 1000 ohm resistors, do they need to be of specific voltage requirment?

Sorry, my bad, just finished reading the requirment list and now I see the .25w spec. Thanks again for this Thomvis, thanks very much. Cheers!

Excellent info

Does anyone else want me to make you a set up?
Michael

Yes Yes I know, I said, I'm building a project YZF1070, K. Well you mix two kids a WCB appeal, bringing a BMW 850i up to snuff & then some, mix in a little depression and .......



K, Yeah, I know excuses are just like a,holes; everyone's got one

I will be starting some day??.

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ThomVis
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Re: Home made gear indicator for the YZF750 (and other model

Postby ThomVis » Mon Dec 10, 2012 4:06 pm

You could use a 14 or 16 segment display for better looks, but I personally don't think the extra soldering is worth it.
The 7 segment display used has a dot (DP) in the lower left corner. Another guy let that light up when power to the GI was applied (just needed an extra resistor and a line to the frame), he liked to be able to tell the difference between "unit not powered" and "stuck in between gears". When I ever have to redo one.......

There are also possibilities in simplifying the matrix. A and D segments alway light up together when you don't use 7 of "n". I just too lazy to figure out if you can dump the resistor along with the diode as well.
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sickle44
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Re: Home made gear indicator for the YZF750 (and other model

Postby sickle44 » Mon Dec 10, 2012 4:36 pm

BTW, Thomvis,

With 12V being supplied to the display unit, I'm assuming the diodes are being placed in the direction so they are allowing a negative trigger to go through them and on to the display unit; while blocking any other sort of positive signal to get through, correct?
Michael

Yes Yes I know, I said, I'm building a project YZF1070, K. Well you mix two kids a WCB appeal, bringing a BMW 850i up to snuff & then some, mix in a little depression and .......



K, Yeah, I know excuses are just like a,holes; everyone's got one

I will be starting some day??.

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ThomVis
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Re: Home made gear indicator for the YZF750 (and other model

Postby ThomVis » Wed Dec 12, 2012 4:53 am

Let me put it in other words
12 volts are hooked up to the display, and only the connections you make to ground through the neutral switch should light up (b&c when in 1st gear). Te neutral switch can only be on one of the selections in the green box, the gear you select.
So the diodes allow current from the display through the diodes down to the frame. If you leave the diodes out you essentially bundle up all the lines right of the resistors, so everything (a-g) lights up all the time.
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Re: Home made gear indicator for the YZF750 (and other model

Postby spook » Fri Dec 14, 2012 6:07 pm

Great post Thom. Thanks for putting it up. The gear selection side may be useful for those wanting to run traction control or injection maps.


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