Starting Woes...

I haven't used my bike much this winter. Since the start of December
I've only taken it out a handful of times - every couple of weeks or so.

After leaving it maybe three weeks it wouldn't start at all with the
electric starter. It would hardly turn over. I bump started it, and
took it out for a nice long run - 100 miles or so, and it started fine
after that.

But a week later it was flat again. Bump started it. Went for a 40
mile high speed run - but next morning it was flat.

I bought an Optimate. Left it on charge for a couple of weeks - until
this morning...

It wasn't *completely* flat, and eventually it started with the
electric starter, but it turned over very sluggishly. I took it for a
25 mile blap then had to stop for Petrol. After filling up it was
still sluggish turning over. That suprised me. It had only been
turned off for a few minutes.

I got home & checked the voltage (across the battery). 14.7V at 5000
RPM - the minimum in the acceptable range (14.7 - 15.5) given in the
Haynes manual. But that was with the lights turned off. When I turned
them back on it was 13.5V at 5000 RPM - and only 11.2 at Idle.

I cheked the voltage regulator (resistance betweem the terminals,
resistance between the terminals & ground, etc.) and it was all as it
should be according to the manual.

BTW - I bought a new battery in about August.

Anyone know what to suggest:

1. It being sluggish turning over after 2 weeks on an Optimate
suggests to me that the battery must be shagged. But it's a new-ish
battery.

2. And it turning over sluggishly after stopping for petrol after a
25-mile blap suggests the alternator - or regulator. It wasn't a
completely lunatic blap (it was a bit wet out there) - but it was fast
enough that even the most knackered battery should have been bought to
life - at least for the 5 minutes it takes to fill up.

3. Is the voltage OK? The Haynes manual doesn't say whether you
should measure it with the lights off, on, or whether it should even
matter.

Any one got any clues ??? Battery? Alternator? Regulator? Something
else ??

TIA!

 

at 5k rpm the CBR6 alternator is only just about starting to charge the
battery - try the measurement with the lights on at 7k. Should be back
to 14.7V. If so then your charging circuit would appear to be fine.

not likely to be this then

If your charging circuit checks out as above then you have to suspect
the starter circuit. Check the leads first. Most likely is a corroded
earth. If the leads check out then you may need to recondition your
starter motor. If possible, swap one from a mate's bike to see if the
fault transfers to the other bike before you go shelling out cash.

 

Check the connections, particularly the earth straps.

Otherwise its likely to be the battery. Too knackered to take or hold a
proper charge.