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Discussion Starter #1 (Edited)
Right te hoe
Hope someone might shed some light for me.
My CDI box blew last week and i have just replaced it with another one, and today that one has gone too!!!.
Would anyone know why it's doing this?
Would appreciate any help on this one.
Cheers
 

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Was the replacement a new or used unit?
How did the bike run with the replacement unit (did it run fine or was there some lingering problems?).
How is the output from the regulator/rectifier? Is it below 15.5V at 5000 RPM?

The possibilities that come to mind is a short in the wiring that could kill the semiconductors in the converter unit (but that would cause misfires), or if the regulator/rectifier is bad and the overvoltage is killing the unit (but that would tend to kill the battery and possibly everything else).
Or if the unit is used, then it too failed due to age.
 

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Discussion Starter #3
Hey Sub
The unit was a second had one.(had to get it over from aussie)maybe thats the prob lol.
The bike was runing normal.
Now thats what i need to find out as i did'nt do any tests.
Well i do know of someone else with a SP so i shell see if can will borrow his and do some tests.
Will keep you updated,
And many thanks :)
 

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Discussion Starter #4
Well managed to borrow a CDI and got today running today.
Reading 14.35v charging.
Will do some more checks on it tomorrow.
 

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I had a similar problem. I searched all over the forums and found no evidence CDi's were prone to blowing. Checking the bike I found that the previous owner's workshop had extended the wiring for the CDI using crimp connectors and I figured occasionally a spark might jump across some terminals and cause a short. Disliking crimp connectors, I soldered and heat shrunk the wiring properly and it's never had a problem since.

So look out for wiring modifications. It could be the cause of your problem. New CDi's are expensive, so worth looking till you find the cause or it's likely to happen again...
 

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Discussion Starter #6
Cheers for that mate.
The bike is not with me at the moment so hope do do a bit more looking tomorrow night.
Yes they not cheap and ca'nt seem to find one over here.
Got to get it right.
Thanks again :)
 

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No worries. If you get stuck, let me know. I have a brand new SP2 CDi (Still sealed in it's bag) I keep as a spare here. Would have to be sent from Japan though.
 

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If there's anything I can do to help with shipping? I have no idea what costs are, but I can order stuff and send it where ever. I'm in Northern California, and I have a decent source for dealer parts. Just offering...
 

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Discussion Starter #10 (Edited)
Thanks guy's
Had a good look tonight,only bit evidence i could see
is that the main positive lead onto the battery was getting a bit to close to the frame,
but no signs of arc'n out.
Maybe maybe not.
Still looking.
Doh
 

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Discussion Starter #11 (Edited)
Update
Victorian Motorcycles in Aussie are sending me another Convertor Uint(CDI)
over and looking after me big time :) (should be here in a couple of more days)
In the mean time i have been trying to find a fault,and maybe found a couple of things??
Hard to say really but hope all goes well!!
 

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Discussion Starter #13 (Edited)
Update
Well its been awhile so this is how it goes just incase anyone else has this problem.
I have been through 3 x CDI boxs.
1st one blew and was replaced!!
2nd one blew and there must be a something wrong,checked wiring and found a couple of problems and also checked the regulator rectifier and seemed to be charging a ok.
3rd time round it also blew.In both cases I managed to get about 75kms out of the bike before it died on me.
So I repleced the CDI unit again!!
Then checked out the wiring again and replaced the regulator rectifier unit and was told the coils might also be a problem so replaced both coils as well.
Now i have just got bike bike giong again and have traveled 180kms on it so far and all seems to be goin well.
I will get out on the SP2 again tomorrow to make sure but in the end it might of been a coil problem me thinks but not sure!!
Heres hoping but it feels soooo goood to be back on board :)
So thanks guys and to Victorian Motorcycles in Aussie and RC51.com which supplied me with the parts needed!!
 

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Update
Well its been awhile so this is how it goes just incase anyone else has this problem.
I have been through 3 x CDI boxs.
1st one blew and was replaced!!
2nd one blew and there must be a something wrong,checked wiring and found a couple of problems and also checked the regulator rectifier and seemed to be charging a ok.
3rd time round it also blew.In both cases I managed to get about 75kms out of the bike before it died on me.
So I repleced the CDI unit again!!
Then checked out the wiring again and replaced the regulator rectifier unit and was told the coils might also be a problem so replaced both coils as well.
Now i have just got bike bike giong again and have traveled 180kms on it so far and all seems to be goin well.
I will get out on the SP2 again tomorrow to make sure but in the end it might of been a coil problem me thinks but not sure!!
Heres hoping but it feels soooo goood to be back on board :)
So thanks guys and to Victorian Motorcycles in Aussie and RC51.com which supplied me with the parts needed!!
Might want to carry a spare wiring harness from rc51parts.com. If you contact Ben, he may get you what you need. I know he has several in stock now. This is one thing I will be carrying so I can refurbish and keep in good condition.Good Luck!
 

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Good to hear. The only question is whether it was the rectifier/regulator or the stator coils that was killing the converter unit.
Interesting that that was the only unit that was being harmed.

There have been discussions on adapting the current Shinkosen rectifier/regulators in place of the OEM units.
The newer units use MOSFET technology and run much cooler than OEM units, plus they're more compact.
 
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