I didn't see a how-to on this so I thought I would post one. This is a fairly simple mod to do and provides quite a few benefits. Why did I do this? The CDI box on my RC51 recently died and left me stranded in BFE. The previous owner said he changed the CDI box out as well 6 months before I bought the bike. I figured I would change the coils out for COP (coil on plug) units just in case a bad coil caused my CDI box to shit the bed. I will also be changing out the regulator/rectifier for a Shindengen unit, which I will post a how-to when complete. In addition I am in the process of reverse engineering the OEM CDI unit in hopes of identifying the failure points and designing a better one that doesn't freaking die all the time. /rant and stuff
What is this mod?
This mod removes the stock ignition coils and replaces them with 600RR coil on plug units. This eliminates some wires and the heavy coils. This mod will also remove what I consider a point of failure for the system, the high voltage wire from the ignition coil to the plug. This mod will not offer any performance improvement, however if you need to change your stock coils out for any reason I recommend doing this mod.
What to get for this mod?
some of these items will be explained more in depth during the how-to
- Your stock ignition coils
- 2x 2003-2009 600RR coils and connectors (other coils might work)
- 2x spark plugs Denso IK27PRZ11 or NGK IFR9H11 + grinder
- 8ft high quality 16awg or 12awg wire
- 4ft expando wire loom stuff
- a few different sizes of heat shrink
- soldering iron and solder
- foam (optional)
- beer (not optional)
- typical tools
- half a brain
Let's get going!
Take the bike apart so you can get to your spark ploogs and marvel at all the cool parts your RC51 is made out of.
We will start by creating our adapter harness. I approach every mod so that I can return the bike to completely stock if I want to. This harness plugs into the bike harness, and then into the 600RR coils.
Remove your stock ignition coils and lop the connectors clean off. Leave some wire left on these connectors, we will be soldering to the wires. I left a little bit of wire on the coils in case I ever wanted to use them again.
Now for the coil on plug connectors. I bought the coils on eBay used. I purchased both the 600RR "ignition harness" and the coils together so that I would have the connectors. The coils are from an 06 600RR. AFAIK
you can use any coil from 03 up. They all seem to have the same part number. You can see this here, though I have already chopped off one of the connectors.
Cut two of the white connectors off the 600RR ignition harness, again leaving some wire that you can solder to. Now we need to make the "extension" wires for the harness. This is where you will need your high quality
16 or 12awg wire.
I got the proper length of the extension harness by simply running a length of 12awg wire through the bike to where our adapter harness would be connecting. So, find where you unplugged the stock coil from the bike harness start running your wire here. Route the wire through the bike as it will be when installed. When you get to the spark plug hole where our cool new ignition coils are going to be, cut the wire to this length (adding 2 - 3" extra for slack). Cut another length of wire that exactly matches the length of the first.
Now we can build our first adapter harness. Take the stock ignition coil connector you lopped off earlier and strip a little bit of insulation off the wires and neatly
solder to the 12awg wire you just cut to the proper length. Do the same for the white connector going to the 600RR coils. I made a diagram that may clarify the conversion harness:
Pretty much point A to B, easy easy.
Make sure you heat shrink over your solder joints. You can use other methods of joining these wires, however soldering is really the best way to go. There will be around 300V going through these connections and they really need to be made well. I covered the entire harness with expando jacketing. Here is one of the adapter harnesses finished.
Using the same method, make the second harness that goes to the other cylinder.
Now we need to remove the spark plugs and replace with new ones. Here is where things get a tid bit more complicated. If you chose the Denso plugs, skip this step as they already have the screw type terminals. Just make sure you unscrew the "tit" before you put the coil on.
The NGK spark plugs do not have the type of tip that unscrews. This type of tip won't fit in the 600RR coils. If you chose NGK plugs you will have to grind down the tip so that it is about the size of the screw type plugs. I did this with a belt sander. You can use a dremel, file, your neighbor's cat, whatever you feel like. I also threaded the tip using a die so that the coil could "bite" into the tip. You could also file a few notches. Here is one of the used plugs ground down:
Install the new plugs in the bike and torque to 13 ft/lbs.
The 600RR coils don't seal with the plug hole properly so here is what I did to fix it. I found some high density, heat resistant foam and made a seal. Here is what it looks like:
Installed on the coil:
Some of you will probably have concerns about water absorbing into the foam ect. ect. It does absorb water, but very minimal. I tested the foam a bit on the bench and it seemed to work great. It should be noted the bike would most likely work without issue with no seal at all. There is a little air dam that protects the front cylinder and the rear cylinder sits under the gas tank, so really I feel this is just to keep debris out of the spark plug hole. Lastly, feel free to get creative here. This is what I did and it works for me.