Author Topic: Loud engine knocking - big end? (Read 7591 times)

NotAnotherHill · « **on:** 24 November 2012, 02:06:47 pm »

Had to abort my ride today. The bike developed a loud knocking sound coming from the bottom end of the engine. When I stopped and revved it in neutral, no knocking. But when riding the knocking is regular and increase with speed. I can also feel the knocking. I'm not at all mechanically savvy, but have a feeling this might be terminal. Any advice?

His Dudeness · « **Reply #1 on:** 24 November 2012, 02:14:28 pm »

did you try clutching it in while moving? so you'd be riding along and pull the clutch in does it still knock?

markbubble · « **Reply #2 on:** 24 November 2012, 02:16:28 pm »

if its not making the knocking when not ridden i doubt its the engine as would more than likely do all time,id 1st check for any thing loose like suspension,wheels,engine! flat tyre or buckled wheel,wheel bearings ,swing arm bearings etc
it hard to say without been near bike but fully check all the safty point before you try ride again!
i ad a similar knocking noise on classic car a few years back couldnt suss it out till one wheel passed me!i was lucky that no major damage happened and still had 3 wheels to 'coast' to a stop on a bike you might not be so lucky!
good luck and i hope its something simple for you

darrsi · « **Reply #3 on:** 24 November 2012, 02:44:19 pm »

May be worth taking your front sprocket cover off and having a quick look to make sure all is well under there?

Dead Eye · « **Reply #4 on:** 24 November 2012, 03:43:27 pm »

I second what darrsi says as for one its only a 2 min job and second I had a knock on my bike when I first got it which was solved with a new chain and sprocket set.

NotAnotherHill · « **Reply #5 on:** 24 November 2012, 04:22:39 pm »

No knocking with the clutch in or when not running power through drive chain. I had the front sprocket done recently and had new chain and sprockets. I'll have a look again but I only checked the nut last weekend and it was fine. Tyres look fine although the rear is due for a change. I'll have a look at the swing arm. Cam chain is rattling a bit but not too bad.

darrsi · « **Reply #6 on:** 24 November 2012, 05:20:24 pm »

Did you buy the modified nut when replacing the sprocket? Check it anyway to eliminate it.

Double check the rear wheel is lined up equally on the notches of the swing arm, if it's misaligned it could cause lumpiness.

Where are you mainly feeling it, left foot, right foot, etc...?

markbubble · « **Reply #7 on:** 24 November 2012, 05:36:53 pm »

yea id deffo check the front sprocket nut and the back wheel is in line(do with stright edge to check marks are correct as well!) maybe run the bike on main/paddock stand and run in thru gears to see if any different

unfazed · « **Reply #8 on:** 24 November 2012, 05:45:41 pm »

Worn front sprocket

NotAnotherHill · « **Reply #9 on:** 24 November 2012, 08:04:53 pm »

New front and rear sprockets along with new chain. Modified sprocket nut on. Took some slack up in the drive chain last week but the bike ran fine without knocking for a 200 mile ride. I'll double check the wheel alignment but I took care when I tightened chain.

unfazed · « **Reply #10 on:** 24 November 2012, 10:33:06 pm »

Chain too tight???
Does it just touch the Swinging arm protector when pushed up with very little pressure.?

darrsi · « **Reply #11 on:** 25 November 2012, 02:22:35 am »

Tight chain will grind rather than knock........

red98 · « **Reply #12 on:** 25 November 2012, 08:07:47 am »

mmmmmmmmmmmmm....i was thinking loose chain knocking on the underside of the swinging arm

.......sounds as if you have double checked these things a few times and no doubt getting a bit fed up with it....try one more time with the chain condition and tension and as always let us know how you get on

Andy FZS · « **Reply #13 on:** 25 November 2012, 09:24:17 am »

I had knocking type noise a while ago, if I closed the throttle it went if I accelerated it returned. After I oiled my chain it stopped. Final fix with Scott oiled.
Good luck
Andy

Sent from my GT-N8010 using Tapatalk 2

darrsi · « **Reply #14 on:** 25 November 2012, 12:10:45 pm »

Is it possible you could put the bike on the centre stand, run the bike, and make a video and post it because it's kind of a difficult one to just guess?

Although you will get a bit of chain slap when you do that.

NotAnotherHill · « **Reply #15 on:** 25 November 2012, 01:07:16 pm »

Found the problem: The plate and the fixing washer that the secured the link that fastened the chain together has come off. The link was half way off. Christ knows what damage it would have done If it had come off whilst riding. Brand new chain as well. I'll be taking it back to the garage that fitted it for them to sort. The sprockets, washer and nut seems ok and I can't see any damage as a consequence.

wezdavo · « **Reply #16 on:** 25 November 2012, 01:25:27 pm »

That could of been very nasty..

His Dudeness · « **Reply #17 on:** 25 November 2012, 01:28:52 pm »

what type of link was it?

markbubble · « **Reply #18 on:** 25 November 2012, 01:33:22 pm »

that could have been realy nasty to you and your bike but least you have found the problem before any damage was done and its not the engine! id be very very carefull if you take back to garage when riding it,maybe they can come to you if its there fault? let us know what type of link it is and ow its failed
realy glad you have found problem and it didnt spit you off bike!

His Dudeness · « **Reply #19 on:** 25 November 2012, 01:36:36 pm »

definitely do not ride it

unfazed · « **Reply #20 on:** 25 November 2012, 02:50:05 pm »

Would not have guessed that , looks like a first day apprentice job. fitted the links but never peened the ends of the rivits.
You have been extremely lucky it did not come apart when riding. A few choice words to the garage I would say is in order.
Let us know how you get on

NotAnotherHill · « **Reply #21 on:** 25 November 2012, 03:31:06 pm »

It was a soft split link which I've since discovered today are not recommended for over 500 cc bikes. I'm going to get the mechanic to come to me and fit a proper split link.

His Dudeness · « **Reply #22 on:** 25 November 2012, 03:33:52 pm »

hah we were discussing that a few days ago on here. think the consensus was not to use them on anything over a 250.

this is the one http://foc-u.co.uk/index.php/topic,5197.0.html

keno · « **Reply #23 on:** 25 November 2012, 04:47:52 pm »

Quote

It was a soft split link which I've since discovered today are not recommended for over 500 cc bikes. I'm going to get the mechanic to come to me and fit a proper split link.

No such thing as a soft split link.
softlink is for bikes over 500-600cc needs to be pressed on then soft rivet end squashed to about 2-3mm more than it was
splitlink under 500-600cc they just clip on-definitely no good for a fazer.

I would check and make sure what was put on your chain.

red98 · « **Reply #24 on:** 25 November 2012, 07:20:00 pm »

glad you found the fault before the fault found you

dont take any flannel from the garage,they NEED to come to you and fix the problem the correct way and of course, foc