COP wiring question

[BOM88]

Hey all,

I am making my own harnesses for the Coil over plugs I bought of ebay. I am using a set of R1 COPs and part of the deal was the R1 harness was included. I used the R1 female plugs for the COP ends and the vmax coil plugs for the other side (mine had some cracks so I decided to cut the plugs off). Looks like everything is fitting up nicely and I would like to keep the harnesses as short as possible.

The question I have is, with the stock set up the front right coil plug wire comes down to the front left and the front left coil plug wire goes to the front right. From my understanding the vmax also sparks on the exhaust stroke so could I actually just hook the front right COP to the front right harness (and left to left)? I was hoping someone has done this and it has worked alright. I would significantly reduce the custom harness length.

Thanks....

 

[[email protected]]

No.

The bike won't run right with the coil wires crossed. I understand your question about wasted spark and not sure of the technical explanation of WHY it won't work but, I know there have been numerous posts on the forum about guys having unexplainable issues after working on the bike and it was found the front coil wires weren't crossed over as they should be. Returning them to the original state fixed the problem

 

[BOM88]

Thanks Mike!

The more I think about it the more it makes sense that it wouldn't work I think I was hoping it would work more than anything!

 

[alorio1]

From what I have read each cylinder fires twice per 720 degrees. Once for power stroke and other for exhaust stroke, but I don't think the ignition advance would be in proper time if the wires are swapped.

 

[gamorg02]

Few folks have mistakenly done that and it doesn't run right, I agree it's the advance, or maybe the cylinders are slightly off of 720°

-garrett

 

[BOM88]

That would make sense seeing that the two front cylinders are firing 180 degrees from each other. So then flipping those two wires would have the front cylinders firing to soon (or too late). I think the idea came from a honda CB175 that has a 360 degree crank and both pistons move up and down at the same time. One is in it's exhaust stroke and the other in compression. It also sparks on every rotation so I guess swapping those wires wouldn't make any difference.

Obviously the max is a completely different beast than that little CB!

 

[leisyman]

Can anyone with electronics knowledge answer my question. What is the electrical reason for inserting a resistor, 2 Ohm?, in series with the COPs for each cylinder? I understand it will increase the overall resistance of the circuit, thus lowering the current. Is the additional resistance load to protect the ECU? I do not know what the standard coil resistance is, so it may be just to increase the load to approximate the Factory load. My Max is a 2007 and ever since adding the COPs the Vboost kicks in about 6500. Not sure why.

 

[Fire-medic]

That's about the correct RPM point for the VBoost to be noticeable. Initial operation is listed here as 6000 RPM

See the Electrical section 7-59 (beginning) for VBoost info.
https://ia800204.us.archive.org/14/...ice-manual/yamahavmaxvmx12-service-manual.pdf




Anecdotal evidence of issues with the early 1985-'89 ignition system (5 wires, and two pick-up coils at the stator/coil charging & ignition system) suggests the early CDI system may be more-sensitive to the electrical load presented to it by a COP system, compared to the 1990-'07 CDI system. Read that as ignition box failures.

There are many threads on here about this topic if you do a search.

 

[Traumahawk]

FM hit it on the head. The stock coils are right at 3 ohm, and so the early cdis don't like the cops that don't have resistors in them. The various cop sticks will affect the vboost opening slightly.