Only sparks with a 400ex cdi

[bhatch21]

I got an 88 250r a couple months ago. Did some tuning on it because I thought it had a jetting issue. Turns out it stopped sparking. Got out the meter and checked everything. Stator and coil were in spec. The engine stop switch checked good so I pulled the electrical tape and inspected the whole harness, it looked great. Bought a used cdi and still no go. Put on older 400ex cdi and immediately got spark. Bought a new old stock 250r cdi and got no spark. Does this just mean I got ripped twice on 250r cdi boxes? Whats the down side of running a 400ex cdi, if it will fire on every stroke and actually run the bike? I've read they have a lower max rpm and different throttle curve.

[DnB_racing]

Originally posted by bhatch21
I got an 88 250r a couple months ago. Did some tuning on it because I thought it had a jetting issue. Turns out it stopped sparking. Got out the meter and checked everything. Stator and coil were in spec. The engine stop switch checked good so I pulled the electrical tape and inspected the whole harness, it looked great. Bought a used cdi and still no go. Put on older 400ex cdi and immediately got spark. Bought a new old stock 250r cdi and got no spark. Does this just mean I got ripped twice on 250r cdi boxes? Whats the down side of running a 400ex cdi, if it will fire on every stroke and actually run the bike? I've read they have a lower max rpm and different throttle curve. Im thinking that you have something not grounded properly.

the way the grounds are to the cdi, between the R and the Ex are a little different
on the R you have a system ground and a isolated IPG ground on the cdi, on the Ex you only have one system ground,

the ex has 5 wires and the R has 6, the grounds making the difference in the amount of wires,

[jcs003]

is it an 88 cdi? there are cases where different model year electrical components wont work properly together.

[DnB_racing]

Originally posted by jcs003
is it an 88 cdi? there are cases where different model year electrical components wont work properly together. yes your right... the ground and power lead for the IPG from the cdi have opposite pin out locations,
the blue/yellow wire and the green/white wires are opposite between the 86 and 87-89 cdi

[bhatch21]

The cdi boxes I bought are both H9-CF552, which I think are 89 model boxes. They should work with my 88 bike. All the green ground wires in my harness were connected together well. The ground point where it's bolted to the bike is clean and tight. I have an extra blk/wht and green wire coming off the harness for a tether switch that aren't used or connected to anything. It actually looks like the factory connections for the key switch. It was this way when I got the bike.

Dnb, tell me more about the isolated ground for the cdi.

[DnB_racing]

Originally posted by bhatch21

Dnb, tell me more about the isolated ground for the cdi. on the ex there is only one ground to the cdi.and its strictly for grounding out the capacitor in the cdi to kill motor,
on the R there 2 grounds in the cdi, that are isolated from each other inside the cdi, one is the kill just like the ex, and the other is for the pulse generator ground,and its separated from the system grounds to be a designated ground for IPG as to not get any interference for the pulse,

If Wilkins reads this Im sure he can explain it much more accurate then me!

ive been trying to dissect the cdi to figure them out, but it hasn't been going as easy as I thought..lol

EDIT: after thinking about it, it MUST??? have something to do with the rev limit on the ex cdi, picking up the signal from pulse generator and limiting the rpms.. with this logic I dont think you would want to use the Ex cdi.... IF im correct lol

[DnB_racing]

Originally posted by bhatch21
All the green ground wires in my harness were connected together well. do you have the green with white stripe wire from the pulse generator isolated from the system ground?if these are together it could be your problem

[bhatch21]

Tks for the wire info. I checked the harness and the grn/wht from the pulse generator is isolated up to the cdi with no splices or breaks. Is the pulse generator grounded by being bolted on to the timing plate and motor? If so, I could have a problem here because there was moisture under the stator cover with light rust and corrosion on things.

On another note, she fired up on the second kick using the 400ex cdi. I was only able to putt around the yard in 1st but it revved fine with no problems.

[bhatch21]

wilkin250r, if you're out there, I was wondering if you have any ideas on how my bike fires perfectly fine with a 400ex cdi but is unable to get any spark with 3 different 250r cdi boxes?

I think dnbracing is on to something with the iso ground, but how do those 400ex guys run a 250r cdi if they don't have that wire?

[DnB_racing]

just for kicks.... put any kill switches in RUN position and check the black /white stripe wire to see if it has continuity to ground. there should be NO continuity... then make sure there is continuity when in off position

[bhatch21]

I only have the engine run switch. I checked that and get no continuity. I also tried it with it disconnected, which would be the same, and still no spark. When i ran it with the 400ex cdi, the engine switch killed the motor like it should.

Do you know where the blue/yellow and green/white wires should be on an '88 4-pin connector. Maybe it has an older motor/harness and I need to swap those around.

[DnB_racing]

Originally posted by bhatch21
I only have the engine run switch. I checked that and get no continuity. I also tried it with it disconnected, which would be the same, and still no spark. When i ran it with the 400ex cdi, the engine switch killed the motor like it should.

Do you know where the blue/yellow and green/white wires should be on an '88 4-pin connector. Maybe it has an older motor/harness and I need to swap those around. did you check to make sure in run the bl/wht is clear to ground just to make sure? and then when you put it in stop the black /white should read to ground,
the key black/white is the same wire that goes to the kill switch so check just to make sure you get the right readings

as far as the wires to the pins those are the 2 wires for the ipg, try swapping and see what happens, they could be backwards with the different year cdi

here is a link to some schematics, they are labeled for different years and options

http://www.exriders.com/vbb/showthread.php?s=&threadid=462117

you do know jcs003 asked about different years yesterday right?lol

[bhatch21]

Yeah, the run switch checks good. No key switch, those wires are open. I just swapped the pulse generator wires and tried it with both CF552 boxes and got no spark. Maybe I'll just be the only person in history to run a 250r with a 400ex cdi, probably stuttering at the top of every gear. :(

[DnB_racing]

ok time for all details!! something must have changed ,,when was the last time it ran with a 250r cdi?

and what was done for mods since, paint, motor, wire, anything that was done, not what you tried to fix, but before, what mods were made??

you might have to do a complete electrical check.. resistance readings of all components and wire checks to make sure all wires are good

[DnB_racing]

it just hit me!!! it has to be the pickup coil (IPG)

notice on this pic on the 400 its grounded through the system ground, not the cdi..
this is why it will run with the 400,but on the 250 cdi it actually needs to go thru the cdi for it to work, and im sure the resistance readings needed for the cdi are more sensitive( it requires it to be within a certain resistance), but on the 400 it just needs ground its not looking for anything else.... again Im not real good at explaining, but clean or replace the ipg... and Im almost guaranty it will work, this is were the difference in grounds in the 2 cdis makes a difference,


here is a 400ex pic to show you what I mean.... compare it to the 250 on the other link I gave you

http://www.exriders.com/vbb/showthread.php?s=&threadid=462117

[bhatch21]

I just find it hard to believe that the pulse generator is bad, given that it fires, cranks, and runs the bike with the 400ex cdi. It also checks within spec, and if the ground wire/connection was bad, it be open and have no reading.

I tried both replacement cdi boxes on my buddies running 400ex and got no spark. Not sure if it's because the bike is missing the ipg ground wire or because the boxes are no good.

[DnB_racing]

were do you live? maybe if you post your home town you can find another member that is within driving range that you can either bring your quad to try there cdi or bring you cdis and try in theirs to check them for sure??? maybe??just an idea!

[bhatch21]

I'm in Jackson, tn. Yeah, I've looked on Craigslist hoping someone nearby was selling one that might let me plug my cdi boxes in their bike. No luck yet.

[sixer3]

something super simple and I may be way off and i don't mean to assume you didn't already know this and I also can't explain why HOwEVER with the older cdi's the enginge has to be cranking at a certain speed in order for it to spark. I think this is the difference between an analog cdi box and a digital one. Again just something to think about if you haven't already.

sorry if I'm way off :) good luck

[bhatch21]

Thanks for the info sixer3. Yes, I have read that the cdi boxes have a minimum rpm for spark and that the kickstart models are higher. I'm pretty sure I can turn it over fast enough with the spark plug out to meet that threshold.