Loud knocking sound from engine when slow/brake to a halt?

[Bateman]

I've recently noticed a loud knocking noise from the engine when I slow down and come to a halt, such as approaching a junction. The engine starts going knock-knock-knock as I pull to a stop, then the noise stops once I have halted. Does anyone have any ideas what it may be - its a 35000 mile 2003 1150GS. Valves were done at 24000miles as part of that service thanks to pikeydave.

 

[cookie]

if it stops when you stop, it's unlikely to be the engine. could be gearbox/transmission or wheel related.

does it knock at the same frequency as wheel rotation?

 

[Shep]

Cracked brake disc?

 

[Bateman]

I'll take a close look tonight when I leave work, and test it out again as I was convinced it was coming from the engine - it sounded like a louder version of that knocking noise that occurs for a few seconds when you first start the bike up. I'll look at the brake disc - that was replaced under warranty 2 years ago because the original one was warped.

Thanks for the responses.

 

[cookie]

bring it to the horton inn on thursday, and see if anyone can diagnose it there?

 

[davegs]

Knocking

Try coasting downhill and brake. see if it still occurs needent be fast if you've
got servo brakes! but it could illiminate the engine as a problem.
dave gs.

 

[Colban]

So,at standstill,out of gear,there is no knocking at all when you rev the motor-correct?.
The problem only occurs when braking for any reason-correct?.
Does it knock if you reduce speed by going thru the gears/just closing the throttle?.
When you brake,a lot of extra load is transferred to the front end.
Do you have anything loose there.Bolts etc.Have you had the front wheel out at all or do you have those nasty servo brakes?.

 

[ianboydsnr]

Rattling pad, it happens on my r1100rt to

 

[DrFarkoff]

Put your finger on the right hand throttle body and try and stop the butterfly quadrant from moving

It could be the cables tight when hot and causing the butterfly to "tap" on the throttlestop

My 1100 does it cos aI can't be arsed to set it all up again and I've a gearbox and a cable to go on So I'll do it all at the same time

 

[Bateman]

if it stops when you stop, it's unlikely to be the engine. could be gearbox/transmission or wheel related.

does it knock at the same frequency as wheel rotation?

I think so, although what I did notice last night is that when I pull the front brake, that initiates the knocking sound, but it continues even when I release the brake, and then stops when I stop.

Cracked brake disc?

Had a good look for cracks and they look fine from what I can see

bring it to the horton inn on thursday, and see if anyone can diagnose it there?

Unfortunately I can't make it but am going to try and come along to the next one.

Try coasting downhill and brake. see if it still occurs needent be fast if you've
got servo brakes! but it could illiminate the engine as a problem.
dave gs.

Still seemed to occur and starts when I hit the brakes.

So,at standstill,out of gear,there is no knocking at all when you rev the motor-correct?.
The problem only occurs when braking for any reason-correct?.
Does it knock if you reduce speed by going thru the gears/just closing the throttle?.
When you brake,a lot of extra load is transferred to the front end.
Do you have anything loose there.Bolts etc.Have you had the front wheel out at all or do you have those nasty servo brakes?.

I haven't had the front wheel off but I think i will change the brake pads this weekend. Never changed them before but hopefully with the threads on here and the Haynes manual i should get it done.

Thanks all for the responses. I'll change the pads and clean the calipers up and see if that fixes it.

 

[Shep]

Alternator loose?

Alternator belt starting to fray?

Disc bolts loose?

Good luck anyway

 

[Steptoe]

Your front disc/s have play . Get hold of a disc and push/pull it - does it move ??