Ignition Control Module

cafechris

cafechris

Been Around the Block
I was putting a new battery back into a 81 Honda CB750C and managed to touch the screwdriver against the left ignition control module and had a slight spark. I tried to start the bike after it has been sitting for two months (welding the shock mount back/bracket after the bolt broke off during a wreck and doing physical therapy on my shoulder caused it to sit) and now it will not start. I pulled the spark plugs and turned it over just to keep oil in the cylinder, but can't get it to fire off-even with spraying some ether in there. I pulled the plugs and there seems to be a slight spark when I set the plug(s) against the case and turn it over. Could I have fried the ignition control module? If so, can I replace the one or do I need the set? If this is not it, I will pull the carbs and sonicate them as varnish may have resulted from the gas (using ethanol free) sitting in the bowls. Perhaps the needle valve or floats are not seating properly and it is flooding out?!
THANKS in advance for any help!
 
Check compression just to eliminate that as a possible problem. The spark should be checked with a strobe light to verify that you are getting both spark and timing correct. If the spark is weak, also double-check the battery and clean all connections. New spark plugs and/or plug wires may be needed.
 
OK> so I checked the compression after work and while not great (125 psi), there was only 5% difference across all 4 cylinders. I will borrow a strobe from a buddy to check spark and timing...Battery is new and all connections are in great shape, from starter relay to battery, etc. (I keep them greased to slow down the corrosion). I changed out the plug wires and caps, but not the plugs. I will stop and pick up a set tomorrow after work as that is all that is left!
So you think the module is still OK?
MUCH appreciated Sonrier!
 
No. But the other things need to be checked anyway and they are much cheaper than a module. You have probably fired at least one circuit but test the other things Matt suggested first and eliminate them before splurging on a new ECU.

If the coils and HT leads and LT circuits are all OK think about alternatives to replacement OEM unit. For example DYNA S or any of the other aftermarket systems that would replace the whole system. Or a GM HEI conversion. Or one of these http://www.cb750partsdepot.com/OEM-Style-CDI-14-0504.htm
 
while this is specific to a cx500 the trouble shoot is exactly the same for the cb750 so this will help you test your modules

http://www.genebitsystems.com/david/MotorcycleElectrical/IgnitionProblems.htm
 
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