Repair your igniter

[Matchless]

Hi Matchless,

Thanks for the reply! I'm curious as to why you would suggest the Bosch HEI for my application instead of the Wells HEI approach outlined on your other .pdf

Also, after looking over the schematic using the Bosch HEI I'm still not clear as to where to put the ground connection coming from my signal generator. Looking through the GS650 schematics on BikeCliff's page some of the 650's have two leads coming from the signal generator and some have three like my 450 does. It looks like your schematic is expecting only two wires from the signal generator. Is this an incompatibility or can I overcome this with a simple modification?

My gut feeling would be to connect this wire to the circuit ground in the schematic. I'm just wondering if there are any issues you can forsee with doing this. Since my signal generator is grounded in the middle I'm guessing the driving circuitry in the ignitor may have to function differently than in the case where you have only two signal generator wires.

What do you think .... any insights?

OK, maybe I should have mentioned it. In the middle of the schematic you should find the Wells connections for the same schematic.
I actually missed your three wire requirement, have a look here. http://www.mediafire.com/file/hmzktoygnyg/GPZheiMod.gif This is not my work and the originating persons name is on the schematic. Hope this helps.

[brad-450Lz]

HEI conversion results for '82 450L

Hi Matchless,

I wanted to follow up with you (and anyone else who's considering an HEI module) to let you know that the conversion did not work for me. I received my modules soldered them up, tested them for functionality using a 1.5V dry cell battery to simulate input from the pickup coils. Everything looked great, it was sparking on command.

However...... when I mounted them on my bike it was a no go. There was much spitting and sputtering and an occasional backfire through the air intake (pods in my case).

After some hunting and thinking I've got the following hypothesis:

These HEI boxes (old chevy type) would spark when the 1.5V battery was REMOVED from contact. Meaning you put the leads across the battery in normal igniter test procedure and the spark would only come when you removed the battery lead. Doing some reasearch it seems that some bikes fire once upon connection to the battery then fire the other side when the battery is disconnected. On the other hand my factory service manual for the 450L states spark shoud occur upon contact. Do you think this could be the rub?

Are these boxes usually only meant for "breaker" type operation where ignition is triggered when the ciricuit grounds? The data would suggest that's what they are expecting to see as a trigger. My bike has an all electronic ignition so there are no points etc... It must be operating on a slightly different system that makes it incompatible with these HEI modules.

Just wanted to share my experiences with you and any others that may be heading down a similar troubleshooting path. Hope it helps someone or helps you help someone .

Hope you're enjoying the cup,

Brad

[Matchless]

Thanks for the feedback. To get it working on the GS1000 at the time the originator helped me to change the values of the components to 'bias' the voltage on the input so that the voltage from the pickups were raised a bit to trigger the HEI module properly for the GS1000 and we got it working.

It may be that your pickups require to be biased slightly different to allow the pulse to properly trigger the HEI modules. Unfortunately its been a long time ago and I have forgotton what we did exactly, but I also measured the dwell angle at the time and we could also see "ghost" sparks with a timing light until we got the biasing right (resistor and diode config) using a sort of try and test approach.

If you want to look into it I may still have a write up he made where he goes into details and it should help you set your bias voltage on the input to push the pickup pulse into the operating range of the HEI.
Send me PM if you need it