Duff battery or duff starter motor….?

Bikermike1411

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Hi all,

So, the saga continues!

Wrangled the pump together again, dropped it back in the tank, hooked everything up, added 3l of fuel and hit go….

Cough, splutter, vroooom!!

Yay! Although it was running a bit rough. I’ve installed a new RH throttle cable, so dug out my Dads morgan carbtune gauges (circa 1990 - mercury filled. (‘Only £7 for a replacement bottle of mercury via mail order’ says the slip in their tube 🫣) and, with the bike running on and off for about half an hour while i fettled the cables and air screws, balanced the throttle body’s and had it ticking over like a sewing machine and balanced at 3000rpm. I was well pleased.

By this point the oil temp light was flashing and the gauge was near the top, so I turned it off. I could have barbecued on the cylinders.

I let it cool down for five minutes, then tried starting it again. There was a loud metallic click/twang then nothing. The dash lights went dead. Turned the bike off/on and it sprung to life. Pressed the starter - same outcome.

A bit of digging and I noticed the negative terminal on the battery was loose. It’s not the right battery - it is, but it isn’t. It’s a screw-terminal ‘power line 51913 AGM’ the guy who owned it before me had bought for it. It fits, but I had to use two motobatt quad adapters to make it work on the gs (it didn’t come with any terminals)

Held the negative in place and everything seemed good. Lights, dash…but the motor won’t turn over on the starter. The starter motor is clicking loudly but not turning the engine.

The engine hasn’t seized (my fear as it got mad hot running stationary in the garage or somehow wasn’t getting oil) as I can turn it easily on the crank end with the plugs out.

I pulled the starter motor and ground it against the engine. Pressing the starter causes it to jump/engage on the starter motor shaft then turn with seemingly enough determination to rotate a planet. It doesn’t whizz round like a scalextric motor, but I’m not sure what it should do…it isn’t seized either.

The battery has…leaked…at the negative terminal. It was very hot to touch too.

Question is….

does the starter motor seem ok, and is the battery duff (possibly due to the iffy connection)

Or

Has a duff starter motor overloaded the battery and caused it to boil up?

Thanks in advance,
Mike
 
I should add…the two big bolts that hold the starter motor in place were both heavily copperslipped.

I know the bike had a new clutch at about 20k miles but I can’t see removing the starter being part of that job, and can’t think of any reason why someone would have taken the starter motor off proper to this (besides it being replaced)

I can take a photo tomorrow…the teeth seemed absolutely fine (albeit with a few light rust spots having been sat idle for 15 years) and the teeth on the flywheel seemed fine from what I could see too
 
Jump start it. If it starts it’s the battery. If it doesn’t it’s probably the starter but as you have had it running I’d be checking the wiring from battery to starter. JJH
 
Do not under any circumstances let it idle for 30 minutes.
Check your oil sight glass, they melt if the engine gets too hot, and can even pop out leaving your engine oil pissing out all over the floor....
if you don’t believe me or think I’m exaggerating try doing a search :D
 
Do not under any circumstances let it idle for 30 minutes.
Check your oil sight glass, they melt if the engine gets too hot, and can even pop out leaving your engine oil pissing out all over the floor....
if you don’t believe me or think I’m exaggerating try doing a search :D
I believe you!

Took me that long to get the TBs balanced…. Thankfully nothing has leaked, but I won’t be doing it again in a hurry.

I suppose it’s possible the bike got that physically hot it’s cooked the battery? It was still giving off 12V, but could be down on amps as it’s leaked?
 
Update…

I replaced the battery with a new one, put the starter motor back in and crossed my fingers….

….no joy 😢

It sort of lazily made half an attempt to turn the motor slowly, then starter stopped and clicked repeatedly, causing the dash to go off.

Damn.

Turned it off, went into the kitchen to wash my hands, then thought I’d try it again…..

Success!!!!!!!!!!

Motor turned on the starter!

Put the plugs back in and dropped the tank on, fired up straight away and ticks over really, really sweetly.

And there was much rejoicing!
 
It’s always nice to sort something out. I’d still caution about wires. Check earth contact and wire. Follow the + lead and check all connections. If it plays up again feel for any heating in the wires. JJH
 
It’s always nice to sort something out. I’d still caution about wires. Check earth contact and wire. Follow the + lead and check all connections. If it plays up again feel for any heating in the wires. JJH
Absolutely!!

The plan is now a full front-back work through/restoration. I’ll check out the wiring as I go through it - thanks for the heads up!
 


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