Here's the story.... My mate Mel has a Gilera Runner 125 moped. It is starting good sometimes after a full charge on the battery but then not. Battery has been checked (shop also changed her plug and filter and charged her for a service ....without solving the problem) Nice of them. When she presses the starter you can hear the selonoid clicking. She puts the battery on charge and even then it does not start all the time. Main light returns to full brightness after attempting to start. I have my own idea's, however would love to hear from someone who is more mechanically/ electrically knowledgeable than me. Any help would be much appreciated, she is in the Plymouth/ Torpoint area                                                                                                                                                                             

Sounds like faultly starter motor,could just need cleaning,or earthing on a good piece of frame,edd                                                                                                                                                                             

Reckon you're right Edd,,, sounds like it is drawing too much current.  Clean the brushes on the motor.                                                                                                                                                                             

thanks pete.                                                                                                                                                                             

Happy with that that was my first thought, bad connection, I haven't seen the bike and its in Plymouth and just going on what she has described, its difficult without getting t mess about with it......it wouldn't be short/ bad earth by any chance?   Oh and she has jumped it from a car battery, can this do any damage...not sure if its 6 or 12 volt??? It should be 12 volt as I heard all mopeds are now adays?????????????                                                                                                                                                                             

I dont know the where's or whyfores but i was told never to jump a bike from a car battery when its attached to a car. It may be an urban myth, but i darent do it in case it does some damage. Anyone know why/the truth???                                                                                                                                                                             

Yeah I heard that too.... but a car battery is good for all 12 volt bike systems and will not damage the wiring if you only start the machine.If you leave it attached, the wire (cables) will get hot with the current resistance and melt the plastic casings and touch thereby causing a short circuit. It could result in causing a fire, in the loom. For safetys sake just leave the car switched of when you use it .   Source: Qualified vehicle electronics engineer                                                                                                                                                                             

I was told it could fry the ecu on the bike...not that i'd know if mine had one or not                                                                                                                                                                              

its still only 12volts,if only used for starting it the bike it should not harm the electrics or the ecu,done it loads of times and never had a problem.                                                                                                                                                                             

itll damage the bike if the car is reved while jumping im led to beleive but ive never had any probs with doing it that way   sound like a dodgey earth ot poor conection on the starter motor to me too waf                                                                                                                                                                              

Thanks for this thread Johnny, hopefully it will sort out your mates problems for her.    dc was always told never start my bike with a jumpstart from a  car so that is good to read about to.                                                                                                                                                                             

Ok jump starting a bike from a car battery….. Providing both vehicles are 12volt and the jump leads are connected correctly and both vehicles electrical systems are in order then there should be no problem. As already mentioned, there should be no need to have the car engine running. However, a real danger exists when disconnecting the jump leads.. What can happen is this. Imagine if you will, the bike starts up and starts charging BOTH batteries at a given rate. Suddenly disconnecting the jump leads from the car battery can cause the bikes alternator to surge, albeit only milliseconds but can peak at a voltage sufficient to spike an ecu.. resulting in a blown ecu. There are two methods to prevent this. The preferred one is to leave the leads connected and run the bike for 10 to 15 minutes at just above idle. Then switch the bike off and then disconnect the leads. If the battery and charging system are in order then the bike will restart ok. Alternately, once the bike is started allow it to idle and switch on all electrical loads, main beam, indicators, stop lights… then disconnect the leads. Any surge will be absorbed by the electrical consumers. I have worked for the RAC for almost 23 yrs and am an ATA master technician and have never had a problem jump starting bikes following the above guide lines. The problem experienced by your friend JTB can be caused by several problems. Bad connections on the following, Battery + and - ,  bad connection on the earth lead to the frame, bad connections on the external and internal contacts on the solenoid (not the trigger wire as you say it clicks) bad connection on the insulated supply cable on the starter, high resistance in any of the above cables or the starter motor itself. Obviously the battery itself should be the first thing to check but if it has been tested and is good then you can rule it out, however, don’t believe everything shops tell you. A volt drop test will soon tell you where the problem is in a matter of minutes. So if you can find someone who knows how to do this you should have a quick answer.Finally, when the bike does start up then don’t forget to check the integrity of the charging system   having just re-read your post you say It is starting good sometimes after a full charge on the battery but then not. Does make me wonder about the alternator too....                                                                                                                                                                                 

Good man Paul thanks for the info...of course we now all know who the resient expert is now and you will BM first point of contact for all mechanical and electrical problems....lol   Seriously cheers for the info...I had slight suspicions about connections and earths but..its not a problem I've really had before unless a rebuild on an AR50 starter motor (Brushes)when I was 16 but that was luck rather than skill lol                                                                                                                                                                             

So does any of this mean Mel's Scooter problems are near being sorted.                                                                                                                                                                                 

Lol, not sure I gave her a few basic things to check herself ( make sure the electrical connections are clean) we'll see how she gets on with that...                                                                                                                                                                             

Johnnytb looks like Mel might have got the problem solved, she has taken off her battery and  it is bone dry so she took it to have it tested somewhere and they said it's had it. The original garage told her it was fine. So hopefully a new battery will sort out her problems, she didn't realise she would need to check the battery levels.   Thanks for everyones help and advice I will let you know if this don't do the trick.                                                                                                                                                                                

She should have gone back to the same shop that billed her for the original battery test and then a service ...its just shoddy and they have blatantley not serviced it.......I would write a letter of complaint to the owner see if she can get some recompence or an apology...something...

think there should be a name and shame the shop post for them that dont do the work there paid for so we can see where not to go