just bought an NC35 - having a bit of a problem

[newtothis]

new member, new to the bike and my first proper post - and it's about a problem. I hope this won't be a recurrent theme!

So there I am riding the bike back home from buying it and it's stopped....dead

It had started run fine, after 5 miles or so I pulled up at a set of lights and the engine cut out instantly. No funny noises, the temp gauge was way down the cool end. Tried to restart and there's nothing, niente, nada, no starter, no relays clicking when either turning the key or pressing the button (should there be?). The lights don't look all that bright but even with the battery down a bit I'd expect to hear something.

I checked the fuses under the pillion seat and they are fine. Flicked the run/stop switch a few times, ignition on and off, wiggled the wiring I could find - all the usual stuff you do at the side of the road in between scratching your head. Oil and coolant are fine, you might as well have a look whilst stood there like a lemon!

The engine turns over when pushed along in gear so it's not seized. Fuel aplenty and tried the tap in both on and res positions.

The only thing that seemed at all unusual was the revs stayed high just before it stopped - but the throttle return seems a tad sticky so it doesn't snap back smartly, that could possibly explain it.

It feels like an electrical issue with the suddenness of the stop, no spluttering etc which might suggest a fuel issue. from what I've read here the reg/rec issue doesn't tend to be instantaneous. Does anyone have any thoughts on a possible cause?

I have to say the guy i bought it from was a star, he came out with trailer (has a garage full of other bikes) and helped me get it to work where it is now. He's offered to pay for the fix so I don't think it's a case of him ditching a wrong'un.

[Neosophist]

Ill reply a bit later when I have some time but first thing comes to mind is the NC35 has a side-stand kill switch right, this isnt faulty / come on has it.

Worth checking the connections / condition as its easy to check

[newtothis]

An update from today's investigations.

Battery was reading just over 12V so I whipped it out (the battery) and stuck an Optimate we happened to have kicking around on it. Showed as OK but a bit discharged - no dire warnings.

The rectifier/regulator has at some point been changed for a different unit, the part number links to scooters, various suzukis and yamaha up to 600's made through the 00's. The 12V out connection was a bit loose and has a touch of corrosion so I suspect it might have been making intermittent contact and not charging the battery...maybe.

I went through Rick Oliver's diagnostic checks and the stator windings all measured the same and within limits, none connect to earth, and all the rectifier diodes check out as OK.

Once the battery was charged she started and ran straight away The running check voltage was high though. OK at low revs but rising to 17V at 5000revs so it looks like a dead regulator. Though whether that's due to the iffy connection or not will never be known.

One other thing I did was take a reading of the current draw. Ignition OFF it was a couple of milliamps, when turned ON (with all lights etc) it was 10amps . So the moral of that story seems to be don't leave it turned on for long before thumbing the button if you want to have a chance of getting started. [on reading that back it sounds a bit finbarr saunders]

So all in all it looks like a rec/reg change and remake the connections and I'm good to go.

YAY!

[JZH]

Output at 5,000rpm is supposed to be 15.5v maximum, and there is no kind of "iffy connection" that could raise the voltage, so your reg/rec is definitely not regulating properly. Overvoltage can be very destructive to the other components in your electrical system--I would not trust that again battery at all after an overvoltage situation--and you should carefully check all of the wiring and connectors for burnt connectors and brittle wires. Good luck.

Ciao,