honda mtx 125 starting problems

[craigmac]

i have an honda mtx 125cc,, i have recently broung an new ignition coil and spark plug, i have lots of wires coming from the magneto, i have checked the wires and i get a shock from the red and black wire,, so i wired that to the coil and also earthed it out on bike frame, but still i dont get a spark from the plug i assume that i am wiring it up wrong would really appreaciate some help
many thanks
craig mac

[davsato]

dont have a clue mate, only varadero owners would read this section you need to get it transferred to 'bike tech'

[AlanH]

Your best bet is going to be to track down a wiring diagram.

This is for early models...

CDI Connections:
2-Pin connector:
Black/Red - coil in alternator
Black/White - Kill and Ignition (kills ignition when earthed)
4-Pin connector:
Green - Earth
Blue/Yellow - Pulse Generator
Green/White - Pulse Generator
Black/Yellow - To Coil

Coil Connections:
Black/Yellow - from CDI
Green - Earth

So, the Red/Black wire from the alternator goes to the CDI unit. The Black/Yellow wire from the CDI goes to the coil. If you've connected the alternator to the coil, it won't work 'cos you've bypassed the CDI.

[matt]

is there anyway of fixing a magneto by anychance as my front headlight is only getting 3.6volts

[AlanH]

Sorry, I can't find my old MTX manual at the moment so I'm not sure whether it's likely to be a regulator/rectifier issue or the alternator itself. If you check out the wiring with the aid of a wiring diagram and multimeter and it turns out to be the alternator, you can get them rewound by someone like Westcountry Windings

I put all my old manuals in a safe place when I was rebuilding my garage and can't find any of them now . Doh!

[matt]

regulator/rectifier and alternato all changed and still only getting 3-6 volts to the headlight any 1 have any idears i need it for the mot

[AlanH]

The alternator you've fitted, is it a used one or a rewound one? Was the reg/rect replacement new or used?

I'd say your best bet is to check through for loose connections and shorts. If you still have no luck, grab a manual off eBay for the testing specs and then test everything with a multimeter to make sure it's doing what it should. You just need to work through the wiring in a methodical manner.