Problem starting my YZF750R Battery or something else??

bklynvx1 · Derestricted Danger Joined: 15 Nov 2004 Karma :

When I bought my 1994 Yamaha YZF750R, the guy told me that I needed a new battery because it wasn't starting by itself. So i bought a new battery and charged it and put it in and it starts sometimes and sometimes it doesn't. It wouldnt start yesterday when it was cold, but today it wasnt as cold and it started. I have charged my old battery and put that in there and it would start sometimes and then sometimes it wouldnt and the same thing happens with my new battery. Is it not the battery? Is it something else? Whats wrong with my bike? Anyone out there with the same model having the same problem? Help please. Also if anyone knows of any good mechanics for bikes in the Brooklyn, NY area please let me know. Thanks.

stryker · Brolly Dolly Joined: 30 Aug 2004 Karma :

When my yam fzr600 battery was dieing, on cold mornings when it wasn't going to start, it only turned over the engine for like 20 seconds total.

The very second I hooked it up to my car battery with jump leads it started straight off.

So, if your lacking a multimeter etc then the simplest test would to try jump starting it off your car next time it won't start.

If you have a multimeter, check the batteries voltage. If its below 12.4v then its not in good shape.
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Now what?

loply · World Chat Champion Joined: 24 Mar 2004 Karma :

Does it have a choke?

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

What do you mean it doesn't start? Does it crank over and just not start? Does it turn over slowly? Does it just click and not turn over? Does nothing happen except the oil light goes out?

All the best

Keith
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bklynvx1 · Derestricted Danger Joined: 15 Nov 2004 Karma :

On a cold day, when i push the start button it would stuggle trying to start and after trying for a couple seconds i would try again and it wouldnt even make any noise that its trying to start , the lights would just be on when i try to push the start button , this happend with the old battery and then when i got the new battery the same thing happens. When I attach cables to the battery and start it from a car or from a charger it would start right up and would run but when i shut it off and try to start it again - it wouldn't start. It is wierd because I bought a new battery and it still has a problem...its starting to make me think its something else. Any ideas?
Yes it does crank over but doesnt start and then after when i try again it doesnt even crank over...whats the deal with it?

Reevo8 · World Chat Champion Joined: 30 Jun 2004 Karma :

regulator/rectifier fault?

bklynvx1 · Derestricted Danger Joined: 15 Nov 2004 Karma :

Sorry, I just got this bike and I am not sure what that is. Can you tell me how to check that to see if thats the problem. THanks

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

The regulator / rectifier unit takes the AC current from the alternator and turns it into a nominal 12V DC supply for the battery.

Normally they fail and stop the battery charging. They sometimes fail so that they overcharge the battery.

Get the engine started then put a voltmeter over the battery terminals. It should be around 13v, maybe a touch more, and rise up to around 14.5v when you rev the engine. If it doesn't go up then the battery is not charging, either a regulator / rectifier fault or an alternator fault. If the voltage goes throught the roof then the regulator / rectifier is shot.

I would also check that the battery terminals are clean, and also check the connections on the starter relay (the bit that clicks when you press the starter button).

All the best

Keith
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