Ok, to start off I am an electronics engineer but not a huge internal combustion engine person.

So after buying an mc28 and finding out how much it is going to cost to really get it running to potential I figure why not just build it a new ignition. For me it’s really not that hard to build a programmable ignition, like i guess the ones Matt from tyga is using on his 28. Now the problem is I have limited ICE knowledge and this could turn out to be detrimental to my motor so at the moment this is a feasibility problem for me and I need to decide if it is worth the effort.

My bike has std card, tyga pipes and cans and modified air box, otherwise pretty standard engine.

So to start as far as I understand the problem with the 28 is that on the stock card the timing is “retarded” at the top end so as to limit the power. Is this statement correct?

From my understanding one wants more timing advance as the revs increase, which means then spark fire earlier and earlier as the revs increase.

Does anyone know what the timing on a std card vs 030 card is like. I am talking in terms of min and max advance during low and high rpm. Really want to know what the maximum advance should be so I don’t try and advance timing too much.

Had a quick look at the flywheel on my bike and noticed there are two sets of pickups at what looks like 90deg to each other. Guess they are one for each cylinder? But on the flywheel there are 4 bumps to create pulses on these pickups. Why have 4 and not just 2?

I plan to map the std ignition in the near future, but not sure when i will have time. By the off chance has anyone done this? If they had and wouldn’t mind sharing that would be awesome? If they have done an HRC too and wouldn’t mind sharing that would be even better as i don’t have one so cant do that.
_________________
94 mc28 SE

Ignition maps are something that are quite hard to secure, it doesn't help that most of the information is probably in Japanese.

I've been trying to think of ways to get that information out, and besides from reverse engineering a PGM, the easiest method I thought of was to simulate a running bike and interpolate results........this has been in my head for atleast two years now but I haven't been able to set up the facilities to do all this yet.

Simulating the ignition is probably easy for an electronics whizz. I'm not one of those, but I can twirl a spanner and use a hacksaw, so I made my 'spark generator' mechanically.

The 4 lobes on the flywheel are not only for spark timing, but also for RC valve operation. I know this as when I was making my box I found that I had to replicate the flywheel lobe timing exactly otherwise I got very strange spark and RC valve control. Diameter of the 'flywheel' doesn't seem to be an issue, but I made mine exactly following the stock dims as it's easier to get the timing right.

What you're looking for is 4 readings over 1 revolution of the flywheel, but they must be timed just like the stock flywheel. So if you think of it as spinning at 1 rpm then you need a reading at 0s, 7.5s, 22.5s & 30s. The final 30s (180 degrees of rotation) would have no readings.

If you can make that box I will have one. I bet it's easy. I can throw a pulse generator together with a 555 chip, but have no idea how to link them or if it would even work.

The stock pickups are variable reluctance, and I think the PGM reads from the trailing edge of the rotor lobes.

quote: "From my understanding one wants more timing advance as the revs increase, which means then spark fire earlier and earlier as the revs increase."

WRONG!

This is how a fourstroke works, but even then it's not a linear advance. A boiler curve on a stroker is asking for disaster!

A stroker tends to advance to max quite early and then retards. The MC28 actually retards to a point where it's practically running on inertia alone! Hence why it makes no mojo. The NSR on pump fuel would want to be around 21 degrees advanced up to about 7000ish rpm, and then retard off to about about 10ish at 11000ish rpm.

I will buy one if you guys can get it right !