Battery problems

Only had my bike a week or so and have noticed that its been a bit slugish to start, which i thought might just be a v twin thing. Just been out for a ride 40 - 50 miles stopped for a *** and it would not turn over when i tried to start it. Pushed it to the nearest car garage and they jumped it with a booster. Rode it home (30 miles ) turned it off and tried to start and its dead again. The last owner hardly used the bike last year and im wondering if this has killed the battery. Any help would be appreciated and how much should i pay for a new battery. Cheers Andy

Static Battery Voltage Test

Prior to conducting this test, make sure the battery has not been recently charged. You must wait at least one hour after charging your battery to conduct this test.

Adjust voltmeter to DC volts (20 volt range).

Place voltmeter leads to the battery terminals. (positive to positive and negative to negative)


Read voltage and refer to the chart below.

State of Charge

12.80v ........................ 100% Charged

12.60v ........................ 100% Charged

12.40v ........................ 75% Charged

12.10v ........................ 50% Charged

11.90v ........................ 25% Charged

less than 11.80v .......... 0% Charged


Starting Load Test


Adjust voltmeter to DC volts (20 volt range).

Place voltmeter leads to the battery terminals. (positive to positive and negative to negative)

Watch the voltmeter as you start your motorcycle.

If the voltage drops below 9.5 volts, the battery has very low capacity and should be replaced.


Charging System Test


Adjust voltmeter to DC volts (20 volt range).

Place voltmeter leads to the battery terminals. (positive to positive and negative to negative)

Start your motorcycle.

Bring engine RPM's up to approximately 3,000

Compare the voltage reading to the specification in your owner's manual.
(Note: the voltage reading should be approx. 14.0 - 14.5 volts to properly charge an AGM battery.)


My bet is the battery is fooked..........i changed mine to a Westco battery used in Harley's, if it can turn them lumps over it will cope easy with our bikes and get yourself an optimate III and plug it in

Cheers bud. Going by my dash my bike is kicking out 12.3 volts. I dont have a volt meter so cant check that way. Have just phoned a battery specialist and they have a ytx14 in stock that they will put on charge for me until i collect it at 5pm. I think he said it was a vatara for £54. Just hope it does the trick as i dont want battery problems when i go thruxton next weekend.

Thats an excellent post BB :thumbup I'm going to print that off for when I need it....

sprocker said:

Thats an excellent post BB :thumbup I'm going to print that off for when I need it....

Click to expand...

Seconded :thumbup

DaveRSV said:

Seconded :thumbup

Click to expand...

Thirded!:thumbup

Glad i was usefull for once...............:thumbup

These bikes are utter *******s. I've never known anything like it when it comes to killing a battery.

I bought a new one 2 months ago and put it on the optimate. Took it for an mot last thurs and forgot to plug it back in, started it on sunday night to make sure it was still ok for the retest monday.
Got it out yesterday and the git was too low to start it.

Went for the ytx14bs bat as well

Personally i think the yuasa batteries are crap, i've had 2 and put on an optimate, both were shagged after winter........I got a westco and it seems to turn the bike over a lot easier and so far seems fine

As i said if the westco batteries can turn over the Harley lumps it should cope with our bikes fine.....time will tell i suppose