Hiya,

Went out earlier, the bike was fine, dropped it a gear and over took someone, and the engine started making a really bad clattering noise, like 2 pieces of wood being hit together, the power dropped off really badly, and the noise got so loud I couldn't hear the exhaust over the top of it. I limped it home, and when sat idling the oil light was flickering, but as soon as the revs went above 2-2.5k it went out and didn't flicker at all.

I have a feeling it's the bottom end, so will drop the oil and keep a look out for metal in it. Can anyone advise what to check first and how to go about diagnose it (preferably engine in situ as I don't have the socket to remove it yet

sounds exactly like whats happened to my nc30....not a good sound is it

nope, makes me really unhappy, was running very well, aside from burning a tiny bit of oil (which is why I kept an eye on the level)

Did you ever find out what went with yours?

nope, im in the process of stripping it down, took the cam covers off to see if there was anything obvious that shouted "im broke"
but no joy, so im guessing its deeper, ie, small end/big end bearing.

Why not get an oil analysis carried out?
They are very good at pinpointing problems before a stripdown.

Phil

There must be something in the air, on friday my nc started losing power and making a horrible tapping noise. Took the cam covers off and checked the valve clearances, and did a compression check but everything looked good. Drained the oil and it had metal fragments in it!! New engine time i think.

Drained the oil, was low (just over 2 litres in the sump) but healthy if grubby, no large chunks or flakes in there and it was dirt brown, not black or gold. Have refilled with fresh stuff, made sure the level was right, still clattering

Half way through the tear down, no loose shims or obvious faults, so think it's deeper, and will have the sump off to see if anything is in there that's too big for the plug hole. More info avail on request, and any help or advice willfully accepted

Sounds fucked to me. Is there anythhing in the oil strainer? If it has decided to die on you then there should be evidence.

A shame mate.

It does worry me that there are more engines dying of late. it sucks

It did to me, it's difficult to describe the noise (one mans knock is another mans clang and all that) I'm going to make sure everything is nice and tight, and will listen to it again, if it still sounds fucked I'll drop the sump, and go from there, the oil was free from metal, which I was hoping for, but will see if there's anything loose in the sump/stuck in the strainer etc

It sounds toast to me, you dont always find obvious damage as the mains pick up then spin in ther housing.
I dont know the NC well so i'd say will taking a side case off allow you to see any outer journals, if so you can see if ther joins are in line with the case split or even missing.