Electrical issues...Need help!

[AMF_23]

Hi all,

I am new to the forum and was hoping to get some advice/help.  My father recently handed down to me his 1979 honda cb750f, which is in beautiful condition i might add.  It had been sitting for around 7 years in the garage without even being started so upon getting the bike I did the necessary changes and maintenance.  It rode great the first couple days but then one day it had trouble starting.  After it finally started it rode good for a few hours then started losing power before it died completely.  So upon investigation I found my ignition module melted and my main fuse crumbled when I touched it.  I replaced the fuses but was wondering if anyone knows what would cause the module to melt before I replace it because those are of course expensive !  I appreciate any help I can get!

Thanks!!!

       

 

[TOOLS1]

Welcome to the forum. I do not know what would make it melt the module, but I would guess a bad connection. When a connection goes bad the electricity does not flow properly, and builds up heat. I would check all the connections. Even the fuse connections. Also I have two CDI modules, for your bike. If, you are interested let me know.
TOOLS

[Re-run]

Now, by ignition module, you mean the key unit? If so, what part of it? I know people have had issues with the back where the connector plugs in. The contacts get dirty and heat up a lot and then melt.

[AMF_23]

The part that melted is where the connector (part # WPS-200) plugs in right next to the main fuse box, with a couple other relay plugs.  It then runs up and is screwed in above the battery, which it was dripping stuff down on.  So would that ignition module cause my bike to lose power and die?  Or could it be a bigger issue?

Thanks again for all the advice so far!  

[LukeM]

If it starts and runs first thing in the day, then gradually dies out, my first guess would be something wrong in the charging system.  If the charging system is working, you'll see between 13.5 and 15vdc at your battery terminals when the engine is running.  If it's at 12.5 or lower, you're not charging the battery.

If you could upload some pictures of what's burnt up on your bike, and where they show up in the Factory Service Manual, that will help narrow down the troubleshooting.

Luke M