Can I use ignition only?

[dan22644]

I have a 1997 Yamaha Vmax that I have been slowly gearing up for a conversion to FI. I have some parts, but I am definitely a 6 months away from diving into the project. The problem is that my Ignition module just died, and a new USED replacement is $150 at best.

My question: is it possible to set up the microsquirt to run spark only? I hate to spend $150 to $200 for a spark control module that I will hopefully not need in less than a year. If there is a way to get the beast running using spark only, then I'm just that much closer to convert to FI later.

Here is what I know I would need to modify:

-remove stock spark control module
-use the two pick-up coils for odd fire wasted spark (it's a 72 degree v4, but it operates the same as a pair of v-twins 180 degrees out of phase)
-replace the four standard coils with four coils that use logic level inputs (like LS1 coils) with two pairs of coils in parallel

The question is, what else is needed for the spark portion to operate (if it is possible)?

Thanks!

[grippo]

Yes your setup should work. Take a look at the cb750 4 cyl wasted spark thread about 13 topics below yours. This was a dual tach input engine like yours. As far as the fuel part, you don't have to connect to the injectors until you are ready. As far as the processor is concerned, it is happily squirting.

[dan22644]

Thanks for the answer, and it is good to know that this could work. It sounds like I will need all of the other sensors (IAT, MAP, TPS, and O2).

However, I have been reading, and thinking about this a lot, and I'm not sure if my engine will work using only two pick-up coil inputs. The Vmax engine (in terms of the crank, con-rods, and pistons) is very much like a pair of Harley-Davidson engines mounted side-by-side. It has two cylinders in a 72 degree vee, mounted to a common crank pin. The problem is that the second set of pistons is mounted to the crank, offset by 180 degrees.

Using wasted spark on cylinders 180 degrees out of phase will not work. As an example, the back two cylinders could be at exactly TDC and BDC at the same time, rather than both at TDC with one compressing (the firing spark) and one exhausting (the wasted spark).

Is there a way to setup the ignition using a crank or cam wheel, where I can have four independant spark outputs with no wasted spark?

Thanks!

[grippo]

It sounds like you are right - each separate engine is odd fire and the two separate engines are odd-fire with respect to each other. So you need 4 ignition lines, plus you need different and large individual offsets for each ignition line.

[dan22644]

Ok, so I think I understand what I would need to do, at a VERY basic level.

1. Add two extra VB921 transistor to the board to provide a total of 4 ignition channels

2. Add a 36-1 wheel, or something similar for crank position

3. Add a IAT sensor, coolant temp sensor , MAP sensor, and wideband O2 sensor (to be ready for FI later)

4. Write the code needed for the four separate ignition outputs

5. Make an ignition table

I would actually be able to use the stock coils in this case, since each VB921 would only be driving a single coil.

I'm pretty sure this is a lot for a beginner to take on, but I am an electrical engineer with a fair amount of programming and a little milling machine experience, so maybe I have a chance??? I wouldn't mind being the one to figure out how to make a Vmax ignition work

On the other hand, I would like to have my motorcycle running soon

[aniimsaj]

I can't wait that someone find out how to make Vmax ignition work with Microsquirt. I have been looking for to find out a solution but with no luck If someone really get Vmax engine ignition work with Microsquirt then I think there would be many happy faces here. Mine is old with four pickup coils and I have been thinking that I could fire two cylinders at the same time. But as earlier mentioned I understood that it is impossible to use Microsquirt ignition in Vmax because Microsquirt has only two lines for ignition inputs and four is needed

Hopefully someone find out the solution and I really hope that he/she posts all the details to this thread. And show that I was wrong.

I already bought Microsquirt because I understood that Vmax engine could be think as a double Harley engine and now I am confused

[Matt Cramer]

How far apart do the cylinders on a VMax fire, in crank degrees? I've had a hard time tracking down that information. It would also be good if you had a picture of the stock trigger wheels.

[aniimsaj]

I will start with a bike again in this winter. Then I will have opportunity to check stock ignition with scopemeter and also a time to take a sidepanel away to see pickup coils again.

As I wrote my old Vmax has 4 pickup coils and newer has only one. As I remember there is two coils quite close to each other and then other twos are, let's say, some 70 degrees from these two. But this is just a guess

If no-one could figure it earlier then I relly want to find this "mystery" myself and will post a story. Meanwhile I just crossing my hand that someone else find it out before me... Most important is to draw 720 degree drawing and last but not least find out how to handle it with Microsquirt.