I only have spark for the first few seconds

[Caferacer1204]

Bike was running perfect for about 2 weeks all of the sudden I go to turn it on and 2 cylinders aren’t firing, I wait sit in the garage and ponder. Go to turn it on once more now only one fires. Long story short by the third time I tried to turn it on no spark to any cylinders.

It will spark for about 5 seconds when grounded to the cam shaft cover but after a few sparks nothing to all plugs

Please help!!!

 

[brettp]

Get out the multimeter and check the coils. Check the grounds on the coils, too.

 

[SenseAmidMadness]

You either have a failure to generate the spark signal, a failing igniter unit, a CDI failure, or a pair of failing coils. The fact that it got progressively worse across all four plugs makes me think it's something that crosses all four plugs and both coils -- the CDI unit, the positive wire going to both coils, the frame ground terminal next to the coils, or something else like that.
Pull out your multimeter and start testing. Somewhere on this forum is the electrical chapter of the Honda CB900F factory service manual which provides comprehensive diagnostic instructions for most of the electrical system components. You should test everything in the spark system that you can test with a multimeter, from continuity at the timing pickups to the spark plug wires.

 

[Caferacer1204]

Brand new coils, brand new plugs, I tested the cdi for polarity and there where no shorts I checked the coils but they are literally brand new, should I check alternator/rotor.


This morning I attempted to start the bike as well strong spark the first 20 seconds then immediately stops. Is something overheating is the air-gap bad what is the situation

 

[SenseAmidMadness]

You tested the CDI for polarity? That sounds like something you'd do when reinstalling it without a wiring diagram. You should be testing it for resistance across specific internal circuits.

The rotor and the reg/rec could theoretically be a problem here if your battery is already low on voltage. Check it with a voltmeter and see if you have less than 12 volts.

It doesn't matter that your coils are new. Test them anyway with an ohmmeter. Pull out that multimeter and test every component that has to do with making spark. It is not glamorous or quick work but that is the only way I can guarantee you'll find the problem.

You haven't mentioned what brand the coils are, or where you got them -- if they're cheapies they could already be leaking current to ground after building enough voltage.