Took the bike out the other day short 1.5 mile ride to a cafe, when I came out the display flashed "low bat" and the starter didnt work, turned it off and on and the bike started fine, went 2 miles down the road left it for 3 hours started fine again. But if I put my meter on it it shows 12.8 v but the other bike shows 13.2 v and the van shows 13.1 v so the meter is either out slightly or 12.8 isnt enough, is it new battery time? Yuasa I am thinking standard battery.
xander, 12.8v should be plenty, I think your meter is out. You can see what happens after a full charge then disconnect the + terminal. Check the voltage about 1 hour after charging then leave it till the morning and check it again, if the voltage has dropped by .2v or more it suggests the battery is on its way. When it says 12.8v on the meter what does the dash say with ignition on and lights off? Are you getting 14v or more on the dash with the engine running?
Sounds like a dodgy/ corroded/ loose battery or earth connection. Make sure everything is clean and tight
Thanks I will check the voltage drop tomorrow, the dash does show low voltage I think like 12.4 it goes up to 13.8 14 when the bikes running, I might go get a battery tomorrow as I am off to North Wales Sunday, with the orher bike battery (a yamaha) showing 13.2 on the meter I think the battery is low at 12.8 thinking the meter is reading high so the yam battery is really 12.7 or 8 and the 749 is really 12.4 or so.
Just a thought .... Peculiar or unexpected voltage readings on lead-acid batteries are sometimes due to the surface charge effect . The battery may show a higher reading than the "true" voltage that is available to do work . Voltage is not a very good measure of a battery's charge state or general capacity , but it's a useful indicator , and I'm sure most home mechanics have a multi-meter . Plenty to read on this great website :- https://batteryuniversity.com/learn/article/water_loss_acid_stratification_and_surface_charge PS - Anyone who wants to get serious about battery testing might like this - http://www.actmeters.co.uk/battery-testing/612-6v-12v-battery-tester I've used one , and it is the business , but it's a lot of beer tokens ....
New battery in, reading 12.4 on the dash, needs a charge as that was out of the box, I put an extra earth strap on while I was there, bike definitely starts easier, does taking the battery out reset anything? it stalled 3 times on a short ride hasn't done that in quite a while? See how it hoes on the ride tomorrow
North Wales run yesterday, battery now showing 12.6 on the dash when stopped. does seem to drop a volt or 2 when left on for 30 seconds or so, but the bike starts easier (its got the extra earth strap as well now) and seems to almost be running better placebo effect??
