cdi unit wanted for MTX125

[primalcarl]

I think my cdi unit has packed in, I have changed the HT lead, spark plug cap, the ignition is new and the alternator and coil seem to be working. So it looks like I need another cdi unit. This is proving difficult, or very expensive. Does anyone have anywhere in mind that may have one, and for a good price? Cheers

[devon-tony]

best advice would be to try and find someone with one that you can try on yours, is a lot of money to spend and find it wasnt that, in my personal experience of bikes over the last 15 years or so, I havent ever had a bike with a duff CDi, usually seems like that but it turns out to be a pick up or something else in the circuit

have you tried the obviuos, ie taking the kill switch out of the circuit,

easiest way to source one would be MCN, have a look through the breakers section and give some a ring, or maybe send your unit to a specialist to have it checked.

check a haynes book of lies, think that some of them had a check thing for simple testing of cdi's just need a dvm

best of luck

[dracken1]

i have to agree with tony.
over the years in the trade i've only supplied cdi's to gpz's
and xs650

[devon-tony]

yup and most GPz ones can easily be fixed :) many of the ones that I have seen other people with just need to have the back of the metal case wired to earth, cant remember what model it was, think it was a 550, but bought it for cheap money, got it back home and CDi did appear to be non funtioning, tried the earthing trick and bike worked fine :)

was told by someone about it that did lots with cdis etc, something to do with the earth connection from the pcb to the pin conectors being weak, so an external earth strap sorts it

[primalcarl]

Thanks for that info. I have tried getting readings from the cdi with a multimeter, my manual says what kind of readings I should be getting but I am not getting any. I was thinking of replacing the thyristor after reading this article (http://www.hukrc.freeserve.co.uk/cdi.html) as the only prices I have found so far for a secondhand cdi unit have been £50 plus, and like you say it may not be that. I was riding my bike and came to a junction so stopped, but the bike died. I had the clutch in and tried to restart it but nothing happened. A couple of minutes later I realised I had knocked the kill switch to off and thought this was the problem but tried the bike again with no luck. I am getting a low charge to the spark plug but not enough for a spark. I have replaced the HT lead and cap, and the spark plug is fairly new. The starter coil is also working it seems, and so is the alternator. I will try the kill switch like you suggest and also earthing the cdi. Carl

[primalcarl]

I have just tried the kill switch, it appears fine. I'm thinking now it may be the ht coil, the ohm reading is very high, and there's more power going from it than to it