HELP Electrical Problem - - (Bike Won't Start)

Hi there I need some help to diagnose a problem with my 1997 Suzuki marauder. Went on a ride out on sunday bike started and run perfectly. Stopped for a fag and bike wouldn't start. Checked for blown fuses none found, checked for dodgy wire non found. Thinking my battery is duff I asked a passing motorist for jump leads.  Hooked it up to a car battery, lights and every thing working well didn't at this point turn the engine over as the vehicle that was helping out had too big a battery and the gentleman was frightened on doing my bike more harm. At this point I'm guessing duff battery due to alternator not working. Waited 3.5 hours for recovery back home. Put battery on charge and checked voltage to see if it was charging. 1 day later fully charged battery attached, put key in ignition turn on and battery voltage hit the floor. Not enough power to keep lights on let alone turn the bike over. Next step check wires for obvious signs of wear and tear, corrosion and melting none found. Hooked bike terminals up to car battery, turn bike on, all lights, horn & instrument panels good, try and turn bike over and it sounds like there isn't enough power there to turn the engine over at this point the car isn't running and I didn't see the point in starting the car to test again.
My guess is now that there may not be a problem with the battery other than it wasn't being charged through the electrical system. I can't get the bike started to do any of the other checks so do I assume it's the starter????
Don't want to waste money buying parts when I don't even know which part needs to be replaced.
Has anyone had a similar problem......How do I check which part I need when I can't get the bike to turn over even on a car battery.....

Hello mate,
Electric problems ummmm,, could be anything,,,, Connecting a car battery is ok as long as you don't run the car engine whilst jump starting.  You say
 " . Hooked bike terminals up to car battery, turn bike on, all lights, horn & instrument panels good, try and turn bike over and it sounds like there isn't enough power there to turn the engine over at this point the car isn't running and I didn't see the point in starting the car to test again."

Vz800 marauders have a common hard/slow to start set of problems,, one in particular is the MMM module,,
look at these links mate and see if it is similar to your problem.

https://www.youtube.com/watch?v=gIoCBcOb7ZU

https://www.youtube.com/watch?v=ObdZ8zBScSo

If it is do the mod,,,,,,  Whilst under the left hand side panel where the MMM unit is have a very good look at the wiring,, pull it out,, and check thoroughly,,, very common to have bad and overheated/burnt connections here leading to slow/bad starting.
Make sure battery is good,,,
A quick way to check:-
A 12 volt battery fully charged and in good condition should read about 12.2 to 12.6 volts with no load ( i.e. nothing turned on).
Turn the ignition key on, but don't try to start engine, the voltage should be about the same 12.2 ish volts ,If a  sharp drop is seen when key is turned suspect duff battery or needs charging.

Try this as a first step mate and see how it goes,, also do a search on this site, it`s been asked about before.
Hope this is of some help and good luck mate.

With any starting problem with the VZ, the MMM is always worth bypassing, very easy to do.

On another note, check the battery. A fully charged 12v, six cell, lead acid battery should be around 12.6/7v+. Even slightly higher if it's a really good one one, when its been left to stand overnight and is not under any load.
If you are like me, you will check each cell. in my experience, my bike won't start if it drops below 12.2v (60%).



PS, always start with the easy stuff.

Thanks for the help and advise. Will buy new battery tomorrow and bypass mmm.
Will let you know how I get on.