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Seized nc30

Posted: Sat Oct 10, 2015 5:57 pm
by thebugser
Hi All
My 1992 nc30 has been sitting outside for three years and I'm finally reviving it. I've stripped the carbs and cleaned the jets replaced the oil and fitted a new battery. I've filled up with new petrol. The starter motor clicks when I press the switch but the motor won't turn over. I've tried bump starting with a few mates pushing but everything is really tight. You can hear everything moving from the cylinder heads and the like, but as I say it's not free and the boys weren't fit enough to sustain for very long and the back wheel iocks rather than turn when clutch is engaged. I suspect the oil is completely gone from the bores and that's causing the trouble. Anyone got ideas what is the safest yet easiest next moves short of removing the engine and stripping it to bits?
Regards Pete

Re: Seized nc30

Posted: Sat Oct 10, 2015 7:48 pm
by newtothis
Unless water has got into the bores they generally don't rust too badly, similarly the oil film in the bearings tends to last OK too. Pop the plugs out, put a few cc's of light oil in the bores and leave it to soak. Use a socket or spanner and turn the engine over by hand to see how tight it really is. If you have a torque wrench it probably should take well under 20 lb ft to turn the engine over with the plugs out (that's an etimate not gospel). If it does turn over by hand and isn't too tight then try the starter. You can ususally hear the effort reduce and the cranking sound change as oil pressure comes up. Once the oil light is out when cranking put the plugs back in and try starting.

Re: Seized nc30

Posted: Sat Oct 10, 2015 7:52 pm
by dobbslc
Try a bit of diesel down the bores, it's thin enough to get in all the gaps and also will lubricate the cylinders.
Leave the plugs out and try it again in a day or two.

Re: Seized nc30

Posted: Sun Oct 11, 2015 2:33 am
by Neosophist
that sounds bad.

if the bores have gotten rusted up you might as well scrap the engine.

check obvious things first that are more likely to cause the issues like brakes sticking on / rusted chain

just the front and back wheels and try and spin them by hand.

clicking could be a sticking starter motor relay, ive had that before.. or a bad connection

Re: Seized nc30

Posted: Sun Oct 11, 2015 3:47 pm
by thebugser
thanks for the comments. When I checked the spark plugs on the back right hand one, there was one water in the spark plug pocket out side the engine and that plug had some corrosion so it is possible that a tiny bit of water could have got in. when we were attempting to bump start, when the clutch engaged I could hear everything whirring around very briefly before the back wheel locked so I don't think it's catastrophic.
I'm going to try your suggestions with some lubrication down the spark plug holes, wait a day or two and try hand cranking it. And I'll let you all know how that goes.
Many thanks for the comments.
Pete

Re: Seized nc30

Posted: Sun Oct 11, 2015 7:56 pm
by Dynamohum
Whip the plugs out and try cranking it over to be sure it isn't filling bores with fuel/water the bumpstart attempts are worrying if its flooded the bores you can do major damage with a hydraulic lock .

Re: Seized nc30

Posted: Sun Oct 11, 2015 9:40 pm
by hunter
davethetrucker wrote:Whip the plugs out and try cranking it over to be sure it isn't filling bores with fuel/water the bumpstart attempts are worrying if its flooded the bores you can do major damage with a hydraulic lock .

:plus:

Re: Seized nc30

Posted: Sun Oct 11, 2015 10:16 pm
by thebugser
hi Dave
as I said, there was a tiny bit of water in the spark plug well outside the engine and that plug had some corrosion above the thread. The others were fine. So I don't think very much water if any got in.
I'll definitely crank it with the plugs out and plenty of wd40 or diesel or the like. Thanks for the comments
Regards
Pete

Re: Seized nc30

Posted: Mon Oct 12, 2015 9:07 am
by hunter
What Dave and myself mean't, was the bores could be full of fuel.

Re: Seized nc30

Posted: Wed Oct 14, 2015 1:32 pm
by thebugser
hi there
The tank was off for the entire time the bike was stored so I don't think fuel has been draining into the engine. I have had that issue before where the fuel leaked in, but interestingly the engine turned over but wouldn't start. when i drained the oil it was obviously loaded with petrol.
I will drain the oil as a precaution. I should be sorted by saturday in time to watch the rugby!
thanks for the comments.
regards
Pete