Bike was bought as a non runner...... previous owner says bike had a flat battery and he tried to "jump start" it from a car. Bike has'nt worked since...... with a new battery fitted bike turns over o.k. when trying to start, but has no spark at plug. Could there be a problem with C.D.I. ?

its an alternator not magneto, there should be 3 wires white or yellow, going to the reg\rectifier, multi meter across any pair(unplugged) should show 50-80 volts at 2000rpm non of these should short to earth, multi meter across battery should show up to 14v at 2-3000rpm.with everything plugged back in
if alternator checks out, and no voltage more than 12 at battery , replace regulator,,

all assuming the battery wasn't fried when it ran out of acid

my guess is new stator\alternator required

Personally, unless I was stranded somewhere, I wouldn't jump start the bike. I'd rather recharge the battery and try to start the engine again. But, you may wish to find out why the engine is not starting rather than continue to run down the battery or take a chance of damaging electronic components with a voltage spike. You didn't tell me what year and model the bike was nor whether it's carbureted or fuel injected. If's it's been sitting for an extended period of time, the fuel system may be gummed up due to the fuel evaporating and leaving the gummy residue to stop up the fuel passageways. But, if you still want to jump start the engine, connect the jumper cable directly to the battery in the bike, positive side first to positive post of the battery. Connect the negative from the car's frame or engine to the bikes engine or frame last. This prevents a spark and the possibility of the battery blowing up your face. I've had it happen before and it ain't fun.

Good Luck
Steve

sir,there are 2 reason
1. please check bolts of small fuse connecter near the battery ,sometimes it get loose ,ectually that is main positive connecter to battery
2.please replug the rectifier-regulater cuplers ,otherwise you need to replace the regulater

I am speaking from my Yamaha XS1100, with 4 carburetors.It is a 1980 model, but the carburetors are always gunking up, especially if it sits over winter with gasoline in the tank. This also happens more frequently with the alcohol laced fuel that you have to buy now days. The alcohol causes it to absorb water that mixes with the gasoline and alcohol to form a sticky gunk that blocks up the orifices in the carburetors. The first thing that you can try is to get some Seafoam additive, or maybe Textron. Pour out all of the gasoline in your tank and change the inline filters if possible. Fill the tank with fresh gasoline and add the Seafoam in a generous amount. Allow the bike to sit over night and try to start it. You may get lucky and get the bike to fire up. If it runs rough and doesn't smooth out, you may have to clean your carburetor. See: http://www.bikebandit.com/houseofmotorcycles/2002-yamaha-yz426fp/o/m8901#sch252680

For a breakdown of your carb.

It may have blown a fuse,

Be carefull jumping of a car battery, as when it starts and you give it a rev the car battery will accept more current than the bike can produce and can damage the charge circuit.

Install new plugs, the stock plugs are NGK R CR9E. Clean the air filter. Drain the carb float bowls. Now make sure the gas valve is turned on. Charge the battery with a low amp charger, 3 to 5 amp, overnight. Be sure water covers the top of the plates in the battery before charging. Give the air cleaner intake a shot of starting spray when all is ready. Also, don't believe anything the previous owner said. Many repair parts can be purchased at the following website > Please rate my answer. Thanks.
www.babbittsonline.com/pages/parts/viewbybrand/default.aspx

Hi and welcome to FixYa,

Offhand, even if the the stator / charging coil is defective or for that matter even the regulator, the bike should start and run on a fully charged battery. The only problem would be that the bike would die eventually. If haven't been tried, have the battery load tested not just voltmeter test.

Please postback after the load test. Hopefully by then, I would have the wiring diagram.

Good luck and thank you for asking FixYa.

buy a start monkey this is smallest recharger ever. I take it with me always.just jump it when tou have trouble. this is the best thing to do. forget about benelli, your on your own. steve

Ck fuses and wire connections first. If no problem seen, get bike running and disconnect the ground cable @ battery. If bike dies the problem generally is in the stator or regulator assembly not keeping battery charged. Bike will run untill the battery is too low to keep the ignition system energized and the bike will die. If it continues running w/the ground disconnected, the battery could have a dead cell which will drain the battery in a very short time whether it is running or not.

I think it is likely to be a flat battery - It would be worth topping it up and charging it for a long time then checking the voltage. You could try jump leads as well, but that doesn't work if the battery is really flat.

When a battery is left to go flat it often knackers it permanently (I know this to my cost!), they lose a percentage of their charge every day, especially if they get cold. If the bike isn't going to be used it's best to take it off, keep it indoors and charge it occasionally.