Does anyone have schematics of the gk76a CDI's?

[Nobbsie]

Does anyone have schematics of the gk76a CDI's?
Or know where to find them?
Cheers Nobbsie

[SevenThreeSeven]

You've got me curious...

You're looking for a drawing of the printed circuit board, a.k.a "PCB", (in its bare state)? Maybe with a color-coded/numbered component layout and a referenced parts listing? And specification sheet for the the Integrated Chip that's mounted on the PCB?

Are you looking to build a new one from scratch? Modify? Repair? Improve?

[Nobbsie]

Ideally all of the above.
The plan is to modify/improve it (if I can).
Build from scratch for sure.
Between me and a friend im sure we can reverse engineer one but i dont really want to buy another one or pull my one apart if i dont have to.
also i want to see what the difference between them are eg, sp, standard
but i am struggling to find anything anywhere

[SevenThreeSeven]

Okay, I think your findings (or lack of them) are an accurate reflection of the situation. There just aren't any information sources out there (that I know of) that offer "insider" Suzuki knowledge or engineering data on the CDIs for GSXR400s or Bandit 400s.

About as far as I've ever seen any computer-geek type go is the act of extracting the CDI's ignition advance data-points from the CDI by hooking up bench test inputs to find out how many degrees of ignition advance the manufacturer specified at any given RPM. These data points are then used as background info for other projects, like aftermarket ignition controllers. For example, I've seen extracted ignition advance tables for recent year models of the GSX-R600. They're pretty complex to say the least: the GSX-R600 CDI actually has a complete 16X16 ignition table for each of the 6 gears.

Maybe you could be the first to unravel the mysteries of the Suzuki CDI.

Here's an idea of where you'd have to start to gain an understanding of the CDI's inner workings: I'm pretty sure the CDI isn't even a Suzuki product. I think the sub-contractor for both Suzuki and Kawasaki ignition systems was (and maybe still is) the Nippon Denso Corporation. Their ignition systems (from the late '80s all the way into the 2000s) always used a "Long Tooth" trigger wheel pattern (the trigger wheel is mounted on one end of the bike's crankshaft). These trigger wheels had a number of "short" teeth and one "long" tooth. The Bandit and GSXR400 trigger wheels have 5 "short" teeth and 1 "long" tooth. The Denso Corp is the only manufacturer I know of who used this combination.





In recent years the industry standard for trigger wheels (both for cars and for motorcycles) is the "missing tooth" type of wheel, something like 12-1 or 24-2 or 36-1 or 36-2. Here's an example of a 24-2 trigger. It's from a 2015 Kawasaki EX300. (On the EX300 the trigger wheel is incorporated into the bike's generator rotor)

[moforockband]

The cdi's all differ on 76 models because of Japenese homeland restrictions. They put different cams/exhausts/cdi's etc to bring the power down and meet their regs.
Carmo NL are the experts (you could ask them for a cdi plot graph). Also there's a place in OZ or NZ, can't recall but they may supply info you find handy.
I doubt you will improve it much from std. You'll only find gains if you have modified the bike.
I've dabbled with RGV's and they use Zeeltronic cdi's and throw the suzuki box in the bin. You can then use quickshifter's, 3d ignition curves, program powervalve settings, switch on 2 different solenoids at different rev points. It all gets intense!
There's a chinese unit for the 76, rip that apart?
Ideally maybe you could design a fully programmable old skool Suzuki 4t CDI including quickshifter/adjustable maps?
You need to make it adjustable, as you need to adjust on the dyno the bike to 'see' any gains. near impossible to feel it on the road.
Nick.

[Nobbsie]

Thanks so much for the info guys.
i will start my research lots to think about