Help with spark only setup for motorcycle

[ryan.hope]

I have been doing a bunch of research on the feasibility of using the microsquirt as a replacement for my ignition on my motorcycle. Please review what I am planning and let me know if I am missing anything important.

My plan is to use the microsquirt module and the basica 2.5 bar MAP sensor. For the tach input I want to use the signal from the pulser coil in my stator. This is a potentially high voltage VR signal so it seems like right off the bat I should do the diode fix that I saw sticked in another subforum. Based on some other posts relating to VR sensors, I have a suspicion that due to the size of the pickup in relation to the reluctor the zero-crossing is going to be very wide (there will be a long delay between the positive pulse and the negative pulse). Is there a way to account for this in any of the available firmwares? So besides figuring out the offset angle of the reluctor that should be it right? I can just ignore all the fuel related settings?

[ryan.hope]

Forgot to mention that I would be driving a D555 coil (wasted spark setup) so I know I need a BIP373.

[dontz125]

What kind of bike is this? What tooth pattern does it use?

Spark is far less forgiving of tach drift than fuel.

[ryan.hope]

This is an old 1982 Honda CM450. There are no "teeth" per se but I would assume it would operate like a single tooth wheel... there is 1 pickup coil and there is 1 reluctor on the flywheel rotor.

[24c]

Hi Ryan,

CM450 aka SuperDream over here, parallel twin
Have you got a picture of the existing set up. I might be getting confused but isn't there a removal cam cover on top of the cylinder. I can't remember if an earlier version had a set of points in this.

Mike

[dontz125]

Sounds like a single long tooth. I have an adaptor circuit that will turn that into a square-wave that can be read by the uS' VR or OPTO circuits.

Ryan - Back to your original post; yes, you can simply ignore the various fuel settings. Yes, you need to worry about a long tooth VR, but my circuit will take care of that. Don't worry about high VR voltages; any circuit designed to handle a VR signal will be capable of handling fairly significant AC voltage.

[ryan.hope]

Hi Ryan,

CM450 aka SuperDream over here, parallel twin
Have you got a picture of the existing set up. I might be getting confused but isn't there a removal cam cover on top of the cylinder. I can't remember if an earlier version had a set of points in this.

Mike

There are no points anywhere on the bike. Here is a picture of the flywheel/rotor and the pickup coil.


The brass colored disc at the top of the rotor at the 11:45 position is the reluctor and the pickup is the thing at the 1:30-3 position.



Above is a diagram of the ignition system on this bike. All the diodes show above are inside of the CDI (which I am trying to replace).

dontz125, can you post a pic of the circuit schematic?

[24c]

Hi Ryan,

OK, that brass thing is a single tooth then.
So in theory, if you took the plugs out and hooked up the VR sensor to an oscilloscope, you'd get a typical VR trace.
Is that brass thing or "PICKUP" magnetised or just a plain "zinc passivated" lump of steel?
Just out of curiosity are the holes (balance?) in the stator/flywheel on the same path as the brass thing?

Mike

[ryan.hope]

I am out of town so can't confirm with a physical inspection until this weekend but from inspection of a few photos there appear to be at least 2 rows of balancing holes, one of which is closer to being inline with the reluctor tooth but does not appear to be directly in line with it. I also don't know if it is magnetic or not, I will check this weekend.

[ryan.hope]

I am going to have access to a good oscilloscope this weekend. Besides the ignition signal is there any other signal that I should look at that might be relevant to the microsquirt?