XBR starter motor issue

[niblue]

My XBR500 now has a big new 14ah battery fitted and fully charged however the starter motor is still lethargic and only occasionally capable of starting the bike from cold. There is no sign of any general starting problem with the bike because it almost always starts 1st kick, even first thing on a cold morning.

The starter motor does turn the engine over however it seems to be drawing a lot of power to do that and not turning over the engine fast enough. Could anyone suggest likely causes & fixes for this?

The lack of an electric start wouldn't be a problem if it was just me using the bike but it's intended that SWMBO will also use it and she hates kick-starting bikes.

Cheers
Steve

[guest295]

Check battery voltage: it should be around 13, no less than 12.7. Sometimes a wire in the alternator breaks due to vibration and shorts against the casing. It's easy to fix. If Volts are Ok, remove the starter by unscrewing the long screws on the righthand side and sliding the unit out. Check that the brushes are in good nick (they're long) and clean the commutator. Sometimes carbon dust gets packed between commutator segments, providing an alternate electrical path. Make sure the brushes go back EXACTLY as they came out. Make sure the rotating part isn't rattling round in worn bushes. A wee drop of oil in the bushes does no harm but oil must not get on the brushes or commutator.

[bullet350]

 what oil are you running? on some bikes the oil thickening in the cold can be enough to slow the starter so much that it won't start.

 bullet350

[guest146]

Try connecting jump cables in parallel with you starter wires inc the earth. Its OK to have a big battery but to use that power you need enough cable to pass the current. Do the original cables or terminals get hot or warm when cranking.

Ken

[guest18]

If it were a car I'd say check the comutator brushes, on my XBR I have to confess I just wrote off the electric foot as "pish" (to use the local technical expression) and used the mark one variety   

[niblue]

Finally got round to sticking the electrical tester onto the bike. With the ignition off the battery is reading about 13v across the terminals. With the bike running it's just over 14v so the battery and charging circuit seem fine.

When I press the starter the voltage drops to about 10.5v and after a few goes (with the bike starting each time as it was warm) the resting battery voltage had dropped to about 12.5v.

[guest295]

That's about as it should be. So if there's a fault, it's in the starter, itself. Since it's working when the engine's hot, it may be fine; but cleaning the commutator and checking the brushes may make it work better.