83 Midnight Maxim suddenly dies

I have a Midnight Maxim xj750. Recently, while riding my bike suddenly lost all power. All the electronics did not respond and no switches or horn did not work. I turned the ignition key off and then back on and then turned the kill switch off and on. Then, everything responds again. Any ideas. I can’t see a loose wire but I can’t have my bike suddenly loosing power.

 

One of the key places where this family of bikes weakens with age is the fuse panel. The clips weaken, corrode & get brittle. That is the first place I would start checking. XJ4Ever has a nice kit to replace it with the newer blade type fuses. Or your local auto parts stores have replacement fuse panels. The next step is cleaning electrical connectors. Tedious job but important.

 

I have a 83 MM, and the previous owner replaced the fuse box with inline fuses. It looks like crap but it works, and also confirms there is an issue with the original fuse box. Can I ask you for a favor? My 750 was a multi-year, multi-bike project that I finally got together and street capable. I have one small issue. I had the exhaust off for a while, and when I put it back on, I forgot exactly how the muffler mounted to the rear passenger foot peg arm. I don't know what rubber bushings go in there, and suspect I lost something. The Yamaha parts diagram doesn't show it clearly. Can you take the bolt off the muffler mount and take a picture of the bolts and bushings that hold it on? I have lots of parts left over from my project, and if you need anything, just ask!
Thanks!

 

If someone has already been in there screwing with the fuses you most likely need to REALLY check the connections. I was given a Maxim 750 a couple years ago that had had similar done to it and would not run. It's primary problem was the in-line crimps. All was fine when the connections were soldered and shrink tubing insulated. I would be happy to get you the requested pictures but I no longer have a Maxim. I am sure one of the Maxim inmates will be along shortly to help.

 

the fuse box had already been replaced with blade style fuses. It doesn’t look all that old to me.

 

I would check ignition switch and kill switch first. Make sure kill switch housing is grounded to the handlebar properly.

 

I agree with Franz then. But still check fuse box connections. Make sure they are tight and secure. 38 years of insidious corrosion can make all your connections momentary.

 

you would not be the first person to accidently hit the kill switch when riding

it does not sound like that to me because you lost everything.
Main fuse feeds the ignition switch then the switch feeds all the other fuses.
check the connections of that fuse

so i would suggest this
use a 10 mm socket and a long extension to reach the 2 bolts

Clean and lube the ignition switch

also clean the battery connections check/clean the connector from battery/solinoid to main fuse.

check and clean the voltage regulator connector it may be melted and inturupting the charging system
check the connector at ignition switch.

to go deeper you also want to check the power output of the charging system at 2k rpm you want around 14 to 14.8 volts also check at 3 k rpm .
output should not be higher than 14.8 volts ever.
good read on charging system in this thread
The Ultimate Relay, Switch, Sensor, and Diodes Guide

it may be time to also check out the alternator brushes and that the rotor rings of copper are clean and no oil is present .