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HELP!!! 1978 Yamaha DT 400


Reid
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Hey guys, new to this forum. im hoping you can help me! Today i purchased a 78' dt 400 not running. alot of the wires are not connected in places, and im not familiar with the way dirtbikes work. i dont need the lights and horn/ signals to work all i want to do is get the bike running. there are two small aluminum boxes under the seat which have wires comming out of them , what are they? do i just have to get power to the spark plug or do i need to use the ignition and starter kill switch? anybody know where i can find a wiring diagram? thanks for your help i greatly appreciate it!

Reid

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Hey guys, new to this forum. im hoping you can help me! Today i purchased a 78' dt 400 not running. alot of the wires are not connected in places, and im not familiar with the way dirtbikes work. i dont need the lights and horn/ signals to work all i want to do is get the bike running. there are two small aluminum boxes under the seat which have wires comming out of them , what are they? do i just have to get power to the spark plug or do i need to use the ignition and starter kill switch? anybody know where i can find a wiring diagram? thanks for your help i greatly appreciate it!

Reid

Following your PM I sent a diagram.

...Paul

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Thanks for the wiring diagram Paul! but im stumped, im not going to use any lights or anything, so what are the basic things that need to be hooked up for it to run without a battery? or run at all for that matter.

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You need to look at the wiring diagram and

check the CDI is connected

The ignition coil is connected

The kill switch is connected and is has no continuity to chassis in the off position

you wont need the key switch connected.

All of the above doent mean the bike will spark though, could be something is faulty.

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You need to look at the wiring diagram and

check the CDI is connected

The ignition coil is connected

The kill switch is connected and is has no continuity to chassis in the off position

you wont need the key switch connected.

All of the above doent mean the bike will spark though, could be something is faulty.

Ok i willl try that tonight. then where do i start the proces of elimination. how do i test the ignition coil?

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hey thanks for your help . I made sure everything you said was connected and still no spark. i hooked a battery up to the red power wire and when i did the voltage slowly climes from 0 to about 7.v at about a rate of .01 volts at a time then when it hits 7 volts it drops right back down to about .5 then slowly starts climbing again??? i have no idea whats going . how can i test if the coil is faulty? what should i do!

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