MSD install question

[TopCatGr58]

Jessie,

I went to the MSD site, and looked up the MC-2 ignition system, it IS for Inductive systems as you have read in the online manual. I also found your earlier thread, and the photos showed a different device beside the MC-2 unit, but I can't quite make out the PN#, looks like 4295, but not sure...some retard unit?? That PN# wasn't among the list of devices on the MSD site? Can you tell us what the PN# for that other device is??

The online manual said that the MC-2 unit could be used with aftermarket triggers bypassing the bikes TCI unit, but it doesn't say anything about programming it with a timing curve? SO I don't know or see how it would work and provide the cent. adv. timing curve?? They don't provide as much info about it as I would like!
T.C.

[81xsproject]

The mc2 has no programing available. It works just like the old 2h7 units do (I think) by receiving the already mechanically advanced/retarded signal from the PUC and then firing the coil.

As for the other unit in my pic, it is a retard unit used for engines running some kind of boost. I had initially hoped the I could use it to electronically retard the timing and replace the vacuum system and all movement of the PUC wires. However, I currently don't think it is possible. I haven't found any info on it yet, but I believe that it works by routing the coil wires from the iggy, to the retard unit, and then to the coils. The unit takes 4 pins. Each pin designates a certain degree retardation. Each pin has a matching wire coming into the unit that upon receiving a signal applies the retard to the coils. However, this is all one giant hypothesis that I have come up with by looking at the unit.

[randy]

Those yellow wires are the power wires to the PU coils, you should be able to turn on the power and test them to see IF the TCI is putting out 12 volts to them, that way you can then know if you can just bypass the TCI and connect the MSD directly to the PU coils at that PLUG!

Sorry, TC, but the pickups do not get 12v from the TCI, so if you put a meter on them even with the key on, you'll read zero volts. The pickups generate a very small voltage from the inductive action of the reluctor. They work like a small dc electric generator.The TCI amplifies that signal to switch the coils.

At cranking speed, the pickups will produce about .5 volts peak-to-peak, a little more at higher speeds.

[81xsproject]

I tested the wires going to the PUCs with the key on and one of each pair had ~.475 volts.

[randy]

Well, you learn something new every day! So what does that tell you about using them on the MSD system?

[audijunky]

Tells me he needs to calibrate his meter

[81xsproject]

Well Randy, it makes me think that either I have to get me a 2h7 unit, or come up with one hell of a resistor.

[81xsproject]

Well, I finally called MSD. Basically, if you have 'hall effect' PUC's you can bypass the ignition. But, I don't think that is what we have, so now it looks like I need a 2h7 iggy to run the bike with the mech adv curve and not the one in my 4R0 iggy.

[randy]

Jesie,

Your 4RO iggy has the advance programmed in, why not just keep it and run the TCI outputs into the MSD like the diagram shows?

Oh, no, we do not have Hall Effect pickups.

[81xsproject]

I think I will for now. However, I wanted to try running the 78 advance curve, which has a the most advance of all models.