Recently my engine started cranking slowly, reset the clock, then fired up. I assumed that the battery was weak and slapped in a new one after putting on my battery tender but it does the same thing. Just today on my first commute with the new battery the clock reset and the engine barely fired up. I am not great with troubleshooting stuff. What things does the group think I should test? Wish this bike had a kick starter dammit, Kawasaki!

 

Check and clean the ground connection, and the battery terminals/cable ends if you didn't already do that.

Did you charge the new battery? They don't always come with a full charge.

 

First thing I put the new battery on the charger and it showed charged. Battery voltage was over 13V on the charger. The cable ends looked good but I will look at them harder. As far as ground connections I saw two in the service manual in appendix 17-16 through 17-19: frame ground and engine ground: are these all the grounds I need to locate and check? I am guessing any part of the starting circuit is in play.

 

Correct. Check the big, thick cables first.

If it still is sluggish, try jumping from your car battery. Have the car off as the auto's charging system can overwhelm the bike's.

 

You probably have developed some corrosion on the ends of the positive and negative battery cables attached either to the solenoid or starter or the engine ground.
Ohms law says that a high current load through a little resistance creates a big voltage drop. Clean the cable ends and you'll probably fix your issue.

 

So I finally started looking at it by examining the idler gear and the bushings. Figured I'd rule out any obvious mechanical problem. The bushings looked fine but I thought that the starter motor was quite difficult to spin by hand.
I can't tell if the resistance is normal, like I am feeling permanent magnets, or of bearings going bad. Most electric motors spin pretty easily in my past experience. It definitely did not spin freely by hand. It did spin with the starter button but the headlight dimmed a little. That is with no load so it seems to be drawing significant current which makes little sense as it wasn't externally mechanically loaded. I am thinking the motor is toast but haven't found test procedures in the service manual yet. Thoughts?

 

Take it to an auto parts house. They might be able to test it.

 

1. Your start motor has brushes, it is not going to turn like a 120/208v motor.
2. Cleaning up the - at the battery & frame and the + at the battery.
3. I start a log and record your battery voltage every day.
4. Have you made any modifications to the elec system? If so, that should be checked.
There may be something draining the battery or it may have a problem with the charging system, or you may have a bad battery.
Get the battery fully charged and see what is happening.

 

Thanks. The battery was brand new, fully charged, and the bike cranked exactly like it did with the old battery. So far the connections look clean and tight. I removed the starter motor tonight. It spins by hand with great resistance and a feeling of notchiness that makes me think bad bearings. If I can't find a shop that will test spin it and measure the current, etc., I am gonna disassemble it and do the motor checks in the service manual. And maybe put the spring back on my KACR to lessen the cranking stress the BB351 creates in the motor when starting.

 

OK, you may have a wiring failure in the motor. Don't know how their wired, but you could put a ohm meter on the leads/armature. I looked in my service manual, I couldn't find anywhere where it even mention the elec side of the starter, but I might have missed it!