battery boiling over

[Mark_S]

A mate runs a 650GS, he noticed that the battery breather pipe became detached and some of the battery acid boiled out of the battery and ran down the engine casing. He doesnt know how long the battery has been boiling over.
I thought that the battery shold not boil over and reckon that the alternator is overcharging the battery, prolly due to a malfunctioning regulator. What do people think?

Does anyone know what voltage the alternator generates under normal running conditions. (I expect approx 14V)

Also i expect if the alternator is kaput, the lights would get brighter if the revs were increased.

any thoughts?

 

[Fanum]

Either too much charge.....regulator fekked ( should be allowing 13.6-13.8v, 14 tops) or (depending on battery type) one or more of the plates fekked which is dumping all the voltage over less plates= overcharging= boiling.

 

[Steptoe]

A mate runs a 650GS, he noticed that the battery breather pipe became detached and some of the battery acid boiled out of the battery and ran down the engine casing.

You've just answered your own question. It's what batteries do. It's why they are sealed and have a breather pipe.

The breather pipe allows the battery to vent it's corrosive fumes away from anything thats likely to be damaged.

Your friends bike sounds perfectly normal. Just replace the breather pipe.

 

[rc mad]

well known on the 650, breather pipe drops off and you get nice corrosive acid down the frame and engine.

Tight cable tie around the breather pipe / hose will fix it

 

[oblertone]

I've posted this before ...

... but here you will find a very good step-by-step guide to diagnosing electrical faults on motorcycles

 

[talltony]

well known on the 650, breather pipe drops off and you get nice corrosive acid down the frame and engine.

Tight cable tie around the breather pipe / hose will fix it

+1 The battery on the 650 can need topping up fairly often as it gets pretty hot sitting above the motor and next to the oil tank.
Consider replacing it with a sealed type when the time comes.

Tony