Page 1 of 2

Very loud knocking noise....

Posted: Sun Jun 26, 2011 11:08 pm
by ChowderV4
i know this isnt going to be nice but i need to find out possible causes.
my nc30 has developed a rather loud and worrying knocking sound which i have pinpointed to be coming from the front cylinders.

how terminal am i expecting...... :cry:

Re: Very loud knocking noise....

Posted: Sun Jun 26, 2011 11:10 pm
by Drunkn Munky
Kaboooooooooooooom!!!

Sorry that wasnt very helpfull was it, doesnt sound good tho

Re: Very loud knocking noise....

Posted: Sun Jun 26, 2011 11:11 pm
by alexwitham
The above made me laugh to the point of snorting.

Re: Very loud knocking noise....

Posted: Sun Jun 26, 2011 11:15 pm
by ChowderV4
haha , pretty much what i was thinking......
turrrrrrrd!

Re: Very loud knocking noise....

Posted: Sun Jun 26, 2011 11:21 pm
by Drunkn Munky
You could always cane it round to 14k in neutral a few times, if it throws its toys out the pram you know it was on its way out, if it doesnt you've most likely just fucked it anyway. More great advice :grin:

Has it done big miles?

oh and wheelies, not good for the front cylinders are they???

Re: Very loud knocking noise....

Posted: Mon Jun 27, 2011 1:07 am
by Hadies
Check that the exhaust hasn't come loose at the front. Happened to me last week.

Re: Very loud knocking noise....

Posted: Mon Jun 27, 2011 11:22 am
by Neosophist
Erm, don't EVER rev the bike over 10,000rpm in neutral.

It's written quite clearly in the Honda book, it's the easiest way to break something fast.

The engine doesn't have any load on it so parts explode.

Knocking noise doesn't sound good.. high up or low down?

Could be big end-bearings / top end valves. How's it running?

Re: Very loud knocking noise....

Posted: Mon Jun 27, 2011 6:59 pm
by mick.mh2racing
I'm thinking something simple like exhaust a bit loose or something serious like shell/crank bearings.

Re: Very loud knocking noise....

Posted: Mon Jun 27, 2011 7:48 pm
by ChowderV4
Defiately not exhaust, it's top end front cylinders. Bikes got about 36k oil and filter every 4k and I don't wheelie it. It was running fine prior but now when I rode it last the noise was very loud and it was down on power.

Re: Very loud knocking noise....

Posted: Mon Jun 27, 2011 8:03 pm
by skinnydog0_0
could be a shim missing, causing a knocking sound. Best to get the front head off and check all shims are in place and that the cams are in good order.