Cranking speed nosedives after 5 seconds

[Joker_Da_Man]

I was trying to adjust the points today so hooked up the battery that I foolishly abused by accidentally putting the charger on a higher setting than the required 2A. Boiled the crap out of it and it was my first experience charging a lead acid battery so I didn't realize right away that it wasn't supposed to boil like that. Then after a couple hours I looked again at what setting the charger was on and got pretty mad...

Anyways, I can't get the engine to crank for any appreciable length of time. It cranks at a decent speed for about 5 seconds and then rapidly declines to barely turning over. I hooked up one of those jump start battery packs and no change. Figured that might be dead too so I pulled the Shorai LiFePo battery out of my big bike and same thing. Something must be weak...one of those boxes failing (regulator or something)? I think I've heard of some sort of bypass on the alternator/stator thing...could be that?

If I pull either spark plug and hold it against the engine it sparks fine. Although maybe it is weak or something because it won't set off my timing light (one with an inductor clamp that goes around a spark plug wire). I had never used the timing light before but I verified that it works fine on my car. When I bought this bike the guy said the battery was weak so that was why it had to be kickstarted, but now I'm starting to think maybe there was some other issue too.

On the plus side I did find a something nice today: the spark plug wire end fell right off the spark plug wire while I was adjusting it. I screwed it back in and the plug is sparking fine now. I wonder if that was part of the original problem...although I'm pretty sure it overheated too.

 

[CresentSon]

Ummm... wow. I'm not an expert, but dude please tell me you have a shop manual. There is so much going in that statement that all I can offer is to get the manual out and start trouble shooting everything individually. These bikes don't like to be hooked to starter boxes either.

 

[CresentSon]

Oh yeah, you'll need a multimeter.

 

[Joker_Da_Man]

Yeah I have a shop manual that I am following to set the timing. But if the engine won't crank any length of time then that doesn't work real well. I know I have made some mistakes but don't think I have broken anything except maybe that battery.

I have a multimeter and know how to use it (computer engineer). Was hoping someone would be able to say, "Oh if it won't keep cranking then it is most likely xxxx, here's how to check it." Guess I could page through the appropriate section of the manual again. Also I'm wondering if the timing light I got will be able to work, because the manual says to hook up leads to places on the points mechanism but this one I got seems to (according to its manual) only be able to trigger using the induction mechanism around the spark plug wire.

 

[teazer]

Stops cranking after a few seconds usually points to a battery unable top hold a charge and if it happens with a different battery as well, then it's probably the starter overheating or a really bad connection somewhere that's getting hot.

Try to jump your car battery directly to the starter plus ground without going through any of the bike's circuits and without turning it on. If it dies in 5 seconds it's the starter motor. If it keeps spinning it has to be the button/switch/wiring.