What a timely subject. My Dad and I were just dicussing the timing on this bike. Cant wait for this report.

VFRPILOT:

Are you still a 250 or have you done the overbore? What are your mods so far? I'm on the edge of my seat for this one, I hope everything goes well.

Ryan.

 

Nobrakes,
I found my CDI on ebay! I've been keeping an eye out for one and as soon as I saw it I jumped on it. I paid $145.25 including shipping to get it. I thought that was fair.

Ginsu4u,
Mine is still a 250! I have rejetted to a 128 main with a 40 pilot, drilled the slide, opened the case vent, modified the airbox, removed the emissions garbage, and am running a Big Gun EvoX exhaust.
I guess we'll see if those Japs know what they're doing!

 

The KLX300R igniter is part number 21119-1479. Bike bandit has it for $328 so haunt eBay if you want one.

 

I think we are all on the edge of our seats.

BTW, I think the worst that can happen is that the bike just won't run if its mis-wired. There are several inputs to the CDI which are things like the various lock-outs like the red run/stop switch as well as the combination of the clutch, kickstand, and neutral switches that serve as safety features. I'd say the one you wouldn't want to get backwards would be feeding the wire that goes to the coil into one of the sensors that are hard to replace - like maybe the neutral sensor. I presume that sensor is inside the case and if damaged it might be expensive to fix. The others are just mechanical switches - maybe the neutral is also, but I'm guessing it might be a magnetic Hall type sensor that might be damaged by feeding in the discharge voltage. There is a combination of diodes that serve as a few and/or gates to get the logic right with the clutch, kickstand, and neutra switches to consider, but that diode unit only costs like $20. It is located under the seat, BTW - the little plastic rectangular thing with a black cap on the exhaust pipe side.

That said, I'm glad you're doing it first! No pressure.

 

Bump

Sweet, I didn't see this thread

I'm outta town [:@], and I got a KLX300 CDI sitting at home..........I'm itching for an update.

 

Okay here's the deal!
I am in the middle of trying to get this to work. As you can see from the diagram. there are 11 wires that are pluged in to the 250s CDI. There are only 7 wires on the 300 CDI. The colors on the diagram indicate the grouping of wires in the plugs. The botttom plug that shows only two wires is located above the CDI on our bike and does not go directly to the box. After connecting the wires according to the diagram when the key is turned on everything looks normal but the bike will not start. To make sure that I didn't have to let the smoke out of something I plugged the original CDI in and all was back to normal. I have looked at all the wiring diagrams available in my manuals and all of them show either 7 or 8 wires going to the CDI. I've got some more experimenting to do and have a couple of ideas on where to tap into the White/Yellow & Green/White wires that are shown in the 2 prong plug. But I'm still going at this blind without a acurate wireing diagram for our bike. Any ideas?
I have used Deutz connectors and made it so that it is a simple plug & unplug operation.

 

OK, i hate to be the one to ask this but, what is the cdi? and what would be the gain from switching to a 300 cdi?

 

OK, I'm no expert on the topic, but here's what I know about them...
CDI stands for Capacitor Discharge Ignition and it's mainly responsible for firing the spark plug at the appropriate time.
Old skool bikes used distributors and contact points (just "points") to make and break the electrical connection to the ignition coil, which is what basically timed the spark plug firing.

New bikes use "solid state" electronics (a.k.a. a CDI box) which are more reliable than the moving parts in a distributor. There is usually more inside a CDI than simple ignition circuitry. Often there are "brains" that can alter ignition timing slightly during certain RPM ranges, govern the RPM (stop sparking after XXXX rpm), and probably other things I don't even know about. Our CDI boxes also have the circuitry (I think) which controls the clutch and kickstand lock-out switches (for the starter). Changing to a 300 CDI could possibly give a more aggressive profile to that automatic timing adjustment that happens during acceleration. To put it in layman's terms, we're hoping it'll "make our bikes rip" [sm=icon_rock.gif]. OK, I gotta stop using that smiley.

Gary, when you say it won't start - you haven't overlooked the clutch lever/kickstand lock-out circuitry have you? (Probably not but I had to ask)

 

CDI stands for capacitor discharge igntion. The stator creates the current sends it too the cdi, which then sends it too the coil and plug. The cdi controls how much voltage is getting to your coil.

Kawi wawi you beat me too it, but your answer is much more in depth than mine.

 

I hate to even suggest this, but while you've verified that your old '250 CDI still fires the bike, do you have any way to test the '300 CDI? You mentioned you got it off e-bay so I'm assuming it was used - did the seller vouch for its condition? Is it known good? If you're luck is anything like mine, good old Murphy is always close by.

I can't do it now, but PM me with your e-mail address and I'll take a photo of my manual's schematic diagram and send it your way later this evening assuming you haven't figured it out by then. The diagram is not terribly enlightening w/regard to the CDI - but it does show the various connections and the wire colors of each. Unfortunately I don't have a KLX300 schematic - you really need both, I think. Maybe someone else can provide that. Maybe ask in the KLX300 section of this forum if anyone there can send a copy of their schematic, too?