750 Maxim Not Starting -wiring issue?

I have a 1983 XJ 750 K (Maxim) that I recently bought. Everything is stock that I can tell. The bike sat for the majority of it's life (all indoors) as it only has 7100 miles. When I test drove it, the bike ran like a dream- everything seemed fine and perfect. The former owner said that the kickstand safety switch had given him issues once in a while.

Well when I get home, I would start the bike and it would idle fine in neutral, but when I would try to shift into first, the engine would die. It did this many times until I gave up trying to go anywhere with it. The next day I try to start it and now only the starter relay will click when I push the start button. The bike still does this. The battery is charged to 12.6 volts.

I did some research and some people said that the fuse box (mine is still stock) can give loads of trouble on this bike, but I have not had time to work on it. The starter relay appears to have been replaced in the recent past, and when I tried to short the terminals to start the engine, they did not even spark. I have not tried anything beyond this.

Also, can anyone help get me the proper wiring diagram? (I work with radios, so redoing the wiring should not be an issue).

 

Check voltage on the battery when you try to start it. Your battery may be shot and dropping to nothing when you try.

 

These two things are related. You sidestand switch is either dirty, stuck, or faulty.

Pull the rubber boot off of the switch and spray contact cleaner into the switch body as you move the plunger in and out.

 

Welcome to xjbikes

Stalling when placing in gear is a result of the side stand switch not working properly. The most common problem is the plunger sticks when the side stand is up and the plunger does not extend all the way out, which results in the side stand switch contacts not closing. In a pinch, you can rectify this by manually pulling the plunger out all the way when the side stand is up.

At the end of the side stand switch plunger there is a hole to guide the plunger. Most likely dirt has accumulated in this area and a simple cleaning and lube will correct the problem. If the boot on the switch is torn, you may need to pull the boot back and clean that area also.

The battery is a good place to start. Also be sure the battery terminals are clean and making a good connection. If the battery and terminals are OK, then shorting across the starter solenoid and the starter not spinning would indicate a defective starter. Given the low mileage on the bike, most likely it would just be a poor connection between one of the brushes and the starter motor commutator. Sometimes this can be verified by lightly tapping on the starter, and if effective the starter should be disassembled and cleaned. If needed, here is a nice how to on the starter:

http://www.xjbikes.com/forums/threads/replacing-your-starter-motor-brushes-w-pics.45727/

Your research is correct, however there are a few members that report they are still all original. The stock fuse box fuse holder terminals tend to corrode and break with age, so at the very least a good inspection is in order. If need be, they can be repaired with similar clips, or a blade style fuse box can be installed, which is the most common fix.

http://www.xjbikes.com/forums/threads/how-to-install-an-aftermarket-fuse-box.6350/

Remember it is still a 30+ year old bike, and for safety sake there are many maintenance items that should be attended to when considering the age.

 

Thanks for the info, I'll work on it when I get time. On the sidestand switch, is it supposed to be open or closed when the stand is up?

 

Closed.

 

Link for wiring diagram:

http://xjdiagrams.thundervalleypower.com/

 

Finally got the time to really work on my Maxim. I rebuilt the starter motor with new brushes and now the engine will start. That is it did for a while. Now the starter motor will only kick in after knocking on the the starter motor a few times. Not really worried about that as long as it will kick in most of the time.

Now the thing to figure out, what is the proper cold starting procedure for this bike? My fuel petcock (stock as far as I can tell) has three positions, ON, PRI and RES; I assume that translates as on, prime and reserve. I do have a choke. I can get my bike to start up, but after a while, it wants to die when I twist the throttle with the choke on or off, or it just dies on its own.

 

Clean your carbs.

Check valve clearances.

Do all of the other things.


Starting procedure from cold is the same as any other motorcycle. Starting procedure when warm is also the same. Startign procedure when having sat for a few days involves setting the petcock to prime in order to fill the float bowls, turning the petcock to run, then proceeding as normal.

 

Your starter needs the mica undercut between the segments that the brushes ride on. If the mica is higher than the brass segments the brushes don't make proper contact.

Your petcock should be on the "on" position for normal starting. If your choke is not working correctly would be from plugged enrichment well jets in the float bowls and anything up to the plungers. Carbs pristinely clean is the answer to most of the woes with these bikes. I would suggest to pull the carbs and look up "The Chuch of Clean"
Once the carbs are clean then you will need to check valve clearances before you can sync the carbs in. If all goes well when you start the bike with the choke on it should idle fast and as you reduce the choke lever the rpms should drop. Once warmed up it should respond to the throttle and go back to idle with out dieing out or hanging fast idle.