Battery Boiling?

hey all.

about a month ago the bike didnt want to start in the morning. i hadnt done anything out of the ordinary the day before so when i came to start it all i got was a clicking noise from a small black box the left of the clocks.

i bought a new battery and then it fired up no problem.

today however on the ride home, the bike died on me. i still had enough electricity to illuminate the neutral light and oil light. i wheeled it home and checked the oil, which was fine, and tried starting it again. again the clicking noise from the black box and the bike failed to start.

i also noticed that the battery fluid was boiling and the gas (not petrol) was coming out of the battery overflow pipe.


bike is 88 vfr 750.

also been reading up on the forum, i'm maybe thinking regulator/rectifier, but i have no idea where a) this component is and b) what it does.

Anybody know whats going on?

many thanks

phil

 

On my '98 it is under the seat, bolted to the frame on the kickstand side. A wire harness goes to it. -- Sounds like the recitifier to me. !!Battery gas is hydrogen, VERY explosive. Disconnect the battery fully before doing anything. Do this in a well ventilated place, even put a fan on it from several feet away. -- The failure may affect the stator, zap it too. Sorry. I will send a link to a really good techincal article on this if I can put my mouse on it.

 

Phil, here is the article. It may be too technical to be of really practical help to you. There are good aftermarket rectifiers out there at a lot less than Honda wants. Check with some other guys here on VFR.

http://www.geocities.com/MotorCity/Speedway/6198/reg-rect.html

 

thx very much. is the small box on my bike (on the front subframe, right hand side of the clocks) my r/r?

 

i meant LEFT hand side

 

It's got a bunch of fins on it... My 85 had the exact same symptons as yours... What is happoening is the Rectifier is not dumping enough voltage... You are getting an over voltage from the Stator.. It's then boiling the battery...

If you can get a mutlimeter and while it's idling measure the voltage at the batery.. I'll be willing to bet that the voltage is well above 15 volts even at idle and will jump to even more higher throttle...

A new Rectifier/Regulator can be had from Dennis Kirk for 99 bucks...

 

The regulator is about 3 inches by 4 inches and has cooling fins on it with several wires in a plug going to it. It should be under the seat behind the side cover. As stated before, check the voltage at the battery while running. I'll bet it's way too high. Anything above 14.5v is too high. Look it up on "denniskirk.com" they should have a picture of it. The plug on these tend to overheat and lose connection. Look for melting of the plug, and discoloration of the terminals in the plug. I had to hard wire mine to get rid of a melted plug on my Sabre.

 

Classic r/r overcharging. Hopefully your battery played the part of the sacrificial lamb and nothing else has been damaged but check your connections and wiring for signs of overheating. Mine took out the headlight and r/r connector (18v at idle!)

 

well ive got a new r/r. £17.80 delivered from Ebay! Honda wanted £250!!! Hopefully this will stop my battery cooking off. i'm still kinda worried about that small black relay box by the clocks. apparently this may be the starter relay. is this thing supposed to click when trying to start?

again thx for all the info guys.