[BareKat]

As a little aside to this discussion, I've read of people using the gs1100/1150 part to trigger stuff like nitrous to kick in only in certain gears.

I can't think of a similar application for our Kats but neat just the same.

[GSXFJim]

I'll have to do some looking to refresh my memory on the exact nature of the fact that on the post Kats, the neutral sensor also tells the ignition whether the bike is in 1st gear (or is it second) I'll get my manual out in the morning and check.

I looked at the 98-02 750 schematic and yes there are 3 wires, the neutral wire terminates to the Side Stand Relay and the other 2 go to the Ignition Control Unit as to their exact function I don't know.
The 2 pins are grounded at some point so I make the assumption that if either one is grounded it doesn't let the ICU fire the coils?
Can someone verify this?

I also re-read one of the links farther back in this thread about Mr Cleans' 98+ install and he is vague about reconnecting his GP sensor, in his photo it appears he retains the 2 factory connectors for gears 2 and 3 and the Neutral wire and adds his own.. but there is mention of...

Quote; Mr Clean, "wires 1-6 are your gears"

...but he never mentions abandoning the 2 connections to the ICU or making a parallel connection to them.

The Pre Kats are straight forward, the sensor can be modified with or without the neutral pin, ground the diode like someone did to my bike at some point.
The Post may need further R&D. If the 2 pins can be grounded to fool the ICU that would be simple, if one wanted to do that, if not the 2 pins would need to be paralleled and possibly 2 diodes installed on each circuit so that the GPI unit has no effect in the ICU and vice-versa.

[Astro4x4]

Do you think I can check the timing with a timing light? I'm thinking pull the ignition rotor off, hook the light up and aim the light at the rotor, I should be able to see the spark advance or retard if it is right? Thinking I could check to see what the timing is doing when the bike is in 2nd and 3rd gear. I will check the starting theory in the morning when the rest of the family isn't sleeping.
Throttle position also figures in to the timing on the posts, so if my light theory works I can check what moving the throttle position sensor around does to the timing too.

[ygolohcysp]

I know I've read before that the way the ignition was retarded for "emissions" or whatever it was was by programming in the CDI. My guess was that maybe the contacts for 1st and 2nd might be for triggers to make the CDI use different timing mappings for 1st and 2nd. I mean, it might be able to be assumed on a six speed bike transmission that if you're in 1st or 2nd, you're accelerating, .vs cruising in 3rd or higher. I had considered seeing if I could get a A/F ratio meter with trigger inputs available, and hooking up all six gears (for the gear indicator) to it so I could get a read out of what the engine is doing differently based on what gear it's in.

My third thought for having the sensor/switch be able to read every gear, aside from a gear indicator (#1), and the A/F meter research (#2), was to possibly use the contacts for triggers for one of the dyna-2000 programmable ignitions I could create my own timing maps based on gear, throttle position, speed, etc.

But then, that would be spending a lot of money on a Kat, while basically just turning it into a science experiment. And I'm not even in school.

[GSXFJim]

I doubt it has anything to do with timing.... I copied this from the 98+ manual regarding the ICU and its safety interlock and it's function.

From the manual;
The system incorporates a safety interlock circuit which will cut the ignition if the sidestand is extended whilst the engine is running and in gear, or if a gear is selected whilst the engine is running and the sidestand is down.

It also prevents the engine from being started if the sidestand is down and the engine is in gear even though the clutch is held in.

The engine can only be started on the sidestand with the transmission in neutral and the clutch lever is pulled in, or, if the transmission is in gear, if the side stand is up and the clutch lever is pulled in.

So when the 2nd and 3rd gear pins in the sensor go to ground under the above defined situations it will kill the engine if it's running and tried you try to shift into gear.

Removing the connections from the ICU looks like it won't effect the bike at all.. (this would be subject to test) the only thing that can keep the bike from starting would be the neutral circuit.

Using the GS 6-pin sensor would satisfy the need for the pins for the GPI, the neutral pin of the GS unit, tied to the existing sidestand/clutch switch circuit would keep that portion safety interlock working properly, minus the gear portion as mentioned in the above text from the manual

[Astro4x4]

OK, tested and it has nothing to do with the safety interlocks. The bike will not start in any gear with side stand up and won't run in any gear when side stand is put down. I do recall reading on a Bandit site that they were there, on the European bikes anyway, to retard the timing for emissions and noise control ? I'll see if I can't find the site again in the next few days and post it up. Do the pre '98s have the extra pins?

[GSXFJim]

Do the pre '98s have the extra pins?

My '91 has only 1 pin so does the 88 600 parts bike i have...

[GSXFJim]

** Update**

The boards are done, they are being picked up and the one IC and the programming socket will be soldered then programmed this weekend/early next week, all the other board related parts have been ordered. The cases are ordered as well.. all the parts should arrive next week.. when I'm in San Diego for training so I wont be able to work with them until the following week..

BTW.. here is the finished board after it got cleaned up and IC device changes were made... the circuit on the right will be trimmed off and the SMT 7-seg display will be soldered to as well as the wires back to the control box. This is for the remote/custom mounting.

[Wild-Bill]

Well, it sure LOOKS pretty. What's with the programming, though? You're changing the chips?

[Unholy_m]

I think the programming is for the delay to neutral.

[GSXFJim]

The changing of the chips was for 3 reasons 1 cost and 2 improved functionality of the design and 3 the new ones take up less real estate.

and yes, programming.. the chips are dumb, so a program needs to be written to tell the chips that to do in a specific situation i.e. 1st gear pin go's Low (gnd) so the programming needs to tell the display driver to light up the appropriate segments on the display.. and also the delay between shifts so the you don't see the "n" flash momentary between digits or the neutral itself.

[Wild-Bill]

Cool. Never got around to learning how to program an EPROM myself. All kinds of other useless stuff bumping around in there but not that.

[GSXFJim]

Got the boxes today... here's a better idea of just how small they are... The boards and parts will be here the first week of march..

[MrBrant]

What are you using for an MCU?

I'm curious to know if you run into any latchup/WDT reset issues with the linear power supply. On my gauges (that I haven't had time to touch since last spring) I ran into some of these.

[GSXFJim]

No MCU.. it's getting a Xilinx Cpld