CBR600FM 1991

[Fino]

Riding my old CBR600FM back home from work today, just turned into the end of the street and the engine cut out.

I prodded the starter button and the motor just about turned over but not enough to fire.

On the drive I turned the lights off and tried again - it turned a bit faster but again not enough to fire.

Ten minutes later I tested the battery with a multimeter and it were about 11.5v.

Prodded the starter and it fired up!

I tested the reg/rec connectors with the multimeter as per the Haynes manual and all seemed to be ok.

Is this signs of the regulator / rectifier failing?

Any ideas gents?

Cheers

[lorenzo]

It could be either the reg/rec or just a worn battery. Best way to check would be to start the bike, measure the voltage accross the battery at tickover, then rev it up a bit. As the revs build the voltage should increase too, from about 12.5v at tickover up to about 14.5v about 30%ish up the rev range. The actual revs it happens at and the specific voltage is not crucially important, what is important is that the voltage flattens out and doesn't increase by much more than 0.2v once it's hit its plateau. If this isn't happening and it's going right up to something silly like 18v at high revs then it's certain the reg/rec that's gone, but it might have boiled the innards of your battery too. Check the electrolite levels in the battery and top up if necessary, and you might be able to save it.

[Fino]

Cheers, I check that out tomorrow.

It wasn't that long ago I bought a new battery for it - 6 months or so.

[Mr.Pigdog]

Chances are its the reg/rect unit-loads of hondas suffer with that-also ensure you do it when the engine is warm too(fan cutting in)as they can 'break down'when hot.Could also check the voltage coming out of your alternator as the windings COULD be breaking down-but my moneys on the reg

[ssray]

Check and clean all connections with contact cleaner(halfords,maplins etc) my old vfr melted the fuse block when the rge/rec went. because of dirty connectors.

Ray