...I have searched all over the forum for someone describing my issue and have come up empty handed. Seems like it should be pretty easy to diagnose.

Same old story...it ran fine and then... I jump on it to ride home and I can't get it to start. When I hit the starter button I get this really loud repetitive clicking/knocking noise. I'm not talking like a click-click, I'm talking like a man-that-sounds-terrible-I-might-wake-the-neighbors kind of thudding.

Charged the battery, it reads 12.6 when sitting, 12 with the lights on, and down to like 10 or so when I try to start it. Tried to jump it, same thing. I just barely was able to get it to turn over for a second when I tried bump starting it (grant it I don't have much experience with that).

Starter motor? Solenoid? Thoughts?

Thanks.

 

if it ia a "thudding" noise as loud as you are describing......
I am think it is the bendix gear in the starter itself. The thud might be the gear not engaging right when trying to line up with the flywheel or it might be the bendix gear trying to slide on the shaft it is supposed to slide on and getting stopped due to pitting, rust or corrosion. Everything before the actual starter is electrical and, to my knowledge, wont make that "thudding" noise. I think the solenoid is too little to make a noise like that. seems to me it is the actual starter itself. (either the bendix gear in the starter or the flywheel. oh!
push starting your bike when the battery is fully charged isnt that bad. when your battery is dead and you push start it is bad. your stator starts working overtime to power the bike AND recharge your battery at the same time. only a few times doing that can fry your battery and your stator. (stator - alternator......same thing)

 

i'd start simple and work hard. 1st) charge your battery. Dropping to 10 volts is a little low, but it could be because of the huge draw on it.

Try jumping the starter relay and send some juice to the starter. If it still clicks, then I'd bang on the starter and see if that wakes it up.


Don't forget the #1 rule though. Fresh battery!

 

good point, brveagle

 

If after full charge and you put it the battery on a batt. tester and it goes down to ten... id say its the battery. Bust out the multimeter and check the regulator/rectifier and the stator. (i dont have a f4, and assuming a charging system is a charging system...) You can find specs/intructions in your shop manual. Dont forget to test for leakage also. I have never heard of the bendix going wrong on a cbr (sounds slightly extreme, yet an understandable conclusion) but there is a first for everything. And i dont have the most expierence here either...

 

If it is the battery, I'd be able to start the bike off a jump right? Wouldn't that be a pretty easy way to determine if its the battery or not? Any reason why I shouldn't use a car to jump it?

 

you could use a car, just make sure that the car isnt running when you jump the bike.

but it sounds like the battery. with the bike warm, you should be charging at 13.5-15v up to around 4-5000 rpms. if the battery drops to like 10 when trying to start it, it sounds like the battery has a dead cell. even under starting conditions the battery voltage should not drop below 12v.

check your charging system with a voltmeter starting with the stator, then the rectifier

your stator should put out 50-80v when bike is running. and like i said, the rectifier should be charging the battery at 13.5-15v around 4-5000 rpms.

 

Yes, you should be able to jump start it and as long as the jumper cables are of good quality, it should turn over just fine. I'd pull the plugs on your bike and see how it turns over then. With them out, the engine should turn over very easily. If you hear unusual noises, you've got more problems than just a battery.