I've searched forms for similar problem but no luck.. Have no spark on this 88 TRX300. The coil does not have 12 V on it, only the green wire ground. The CDI Black/white has 12V when switch is on and kill switch is normal. Here are the ohms readings on all the CDI wires.
Green .... Ground (.1)
Blu/Yel .... 366 ohms
Blk/Yel .... .4 ohms
Yel/Red .... open

Blk/Wht .... 12 Volts with power on.
Light Green/Red .. .5 ohms

The Coil has a secondary reading of 9000 ohms and the primary is .4 ohms
The 300 ran last season fine but has not run since this winter. Had the same problem last spring, and took it to Honda and they got it running for $300 and told me the problem was minor....but I neglected to find out what they did. They didn't replace any parts!
I assume I should be able to hold the spark plug against the engine fins and see a spark at the electrode while starter turns over the engine.
I tried to read "DZZY's" appends to see where the CDI wires come from but without luck.
Question.... should I be able to remove the Black/yellow wire from the coil, and hold a jumper from 12V at the battery to the coil (where the black/yellow wire was) and then remove it and see a spark?? This would at least tell me the coil was ok.
Also I have cleaned the coil grounding contacts...
Any help would be very much appreciated.

MicoMan

 

I'm thinking its the CDI box thats the problem, but would like to be sure before spending the big bucks. Any thoughts before I go searching for a reasonable priced box?
Thanks
MicoMan

 

Do you have a service manual for that? If not maybe call around the local shops and ask for the specs on the cdi. If all else fails try Ebay for a used cdi.

 

Ok, I'm flying blind without a service manual, so I guess step one is to get one. Anyone have a recomendation for a good one, or at least one to stay away from... Really interested in details on electrical circuit.
My electrical thinking is that the CDI unit should simply puts out a crisp 12 volt pulse to the coil primary, however when I pull the two leads off the coil and put 12v direct from the battery to the coil, and make/break the connection, I still see no spark. (new Plug). Does the CDI put out a higher voltage?

Any help vasty appreciated!
MicoMan

 

I have a cdi off of a 300 but I dont know what year it fits. It has the rev limiter taken out and the # is HC4, if its the one PM me and we will work something out.

 

I know I'm about a month late with a reply, but I just ordered the new CDI yesterday for my '88 300 FWD. My problem was that it would fire on the first revolution of the engine and then no more until you switched it off and back on. I learned that you could tap on the cdi with a B.F.H. and it would start back working.

 

Thanks for the update. I did see a couple of websites where intermittant CDIs were fixed by carefully cutting away the plastic behind the connectors and resoldering the contacts on the card. I'm about to try that, although beating on the cdi dosent seem to do any good. I did get a manual and all checks ok except no CDI output. I have a 4Volt plus and minus pulse out of the exciter which I think is ok.
Where did you get your CDI (good price?)
Thanks,
Micoman

 

I got my new CDI in the mail today and it got me up and running. I tried the old one before I changed it and like I said earlier, I would get one strong spark and no more until I switched the ignition off and back on. It took about 3 or 4 minutes to install it and it never missed again the rest of the day.

Maybe my 2 pennies worth can help you out.
Lance

 

Do you still have that CDI box you were talking about and if so is it the original one with the rev taken off or an aftermarket one? Also how much would you take for it?

Thanks

 

Just an update... This am I decided to use my router table and cut the bottom of the CDI open. Its a bit tricky as you have to just take the hard plastic off then manually peel small bits of rubber off with your finger nail. A painstaking job, but after about 45 minutes I had a clean circuit board to look at. I could not find any defects on the solder joints, but when I plugged it back in, it runs like a champ!! I will go ahead and borrow a magnifying light and resolder all the connections and I think I'll be in business. Just in case anyone is interested, here are a couple of websites that describe how to open the CDI and common repairs.
http://www.hukrc.freeserve.co.uk/cdi.html
http://www.ta-deti.de/ta/knownproblems.html
I would guess that when all is said and done, I can repack it in bathtub seal (Silicon rubber) and put a piece of plastic over it and then hit the road!!
Micoman[img]i/expressions/face-icon-small-smile.gif[/img]