Turning over very slowly

[Julesholling]

recently my 89 NC30 has started to turn over very slowly. Starts after a while but just wont seem to spin over as quickly as normal. Once she's started then it's fine and runs without problem.

Taken the battery off and charged on an Optimate and all is well with the charge on the battery. Connect the battery back up and she still turns over really slowly but does eventually fire. It's almost as if there is a bad earth or dodgy connection somewhere (checked them and cant see anything)

Also if i stall it at lights when hot it wont start again. Have to leave it for about 10 mins before it will start again??

Any ideas? Rectifier was changed for an R6 one a few months back.

[Malc]

Assuming its being charged properly, I would suspect another dodgy battery, especially if the reg/rec was changed due to a frying issue. The Optimate, although good, is never intelligent enough to tell you the true condition of the battery. Put a voltmeter across it and hit the starter button, you'll probably find its down to around 10.5v, or knackered in other words...

[amaechizzle]

Get it load tested... Just coz the battery drops below 10.5 doesn't mean squat.
Load testing the battery with a proper load tester, will tell you the true CCA of a battery.

"What are CA's (cranking amps) & CCA's(Cold Cranking Amps)?

Cranking amps are the numbers of amperes a lead-acid battery at 32 degrees F (0 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12 volt battery).

In other words, CA/cranking amps determine how much power you have to start your car in most climates. The basic job of a battery is to start an engine; it must crank, or rotate the crankshaft while at the same time maintain sufficient voltage to activate the ignition system until the engine fires and maintains rotation. This requirement involves a high discharge rate in amperes for a short period of time.

Since it is more difficult for a battery to deliver power when it is cold, and since the engine requires more power to turn over when it is cold, the Cold Cranking rating is defined as: The number of amperes a lead-acid battery at 0 degrees F (-17.8 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12-volt battery).

In other words, CCA/cold cranking amps determine how much power you have to start your car on cold winter mornings."

Never know, could a problem with your starter.
And It'll save you wasting money on a new battery...

[magg]

As I commented in another post on a similar subject, if the battery that has been on charge to the point that it has a terminal voltage of 12.8 volts is generally considered fully charged. If the battery voltage drops below 12 volts while trying to start the bike I would think the battery is stuffed. A fully charged battery of the correct capacity will meet the CCA rating, a flat or stuffed battery with the correct CCA rating will not start a bike.

[amaechizzle]

The battery is designed to drop below 12v....

Re-read the previous post.

"Cranking amps are the numbers of amperes a lead-acid battery at 32 degrees F (0 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12 volt battery)."

[magg]

Why is measuring the terminal voltage of the battery while pressing the starter button with the kill switch on not a valid load test of the battery, with one caution do not run the starter motor for more the time required to get the battery minimum voltage reading.

[Neosophist]

If you want to load-test a battery using the starter motor.

10 seconds of cranking is enough

It's also temperature dependant.

http://autorepair.about.com/library/wee ... 01604c.htm

List here of minimum voltages for specific temperatures of batteries.

[amorti]

Not heard of it on nc30's, but for me if it's not the battery (test by bumping off a car battery with car switched off) then I would guess the starter needs cleaning out. Open the casing, clean the carbon dust out, and bob's your father's brother.

[Neosophist]

Not heard of it on nc30's, but for me if it's not the battery (test by bumping off a car battery with car switched off) then I would guess the starter needs cleaning out. Open the casing, clean the carbon dust out, and bob's your father's brother.

I thoght Fanny was your uncles aunt