Knocking noise on non load and acceleration

[jonnyboyg]

Hi Janet,

Your're not wrong.... I have a friend follow me with a magnet....

[Don Madden]

My B*As rattle so much I cannot locate any particular source of noise. (They all do that, Sir.) Cheers, Don.

[clive]

Firstly - I have tried to listen with a block of wood but to honest, as everything is amplified, I still couldn't locate the precise area for the noise.
John

Block of wood may be the problem. A long scewdriver with a nice wooden handle will act as a stethoscope (more useful if you have a medic in the family) and should enable you to locate the source of the noise quite accurately by listening all over the engine whilst it is being revved. Good luck

[SPRIDDLER]

Block of wood may be the problem.
A long screwdriver with a nice wooden handle will act as a stethoscope

Quite so, Clive - and put the HANDLE end to your ear!

(more useful if you have a medic in the family)

Yeah, psychiatrist preferably

[bunners]

I purchased a cheap stethascope from ebay to trace a noise on the B*A A50, I found more noises using that than I thought I had in the first place. I think the only thing original on the A50 engine is the crank cases everything, and I mean everything else has been replaced and it still rattles like a Ba***rd. So I wear ear plugs when I ride it.

[saltbox alf]

Quite so, Clive - and put the HANDLE end to your ear!

Cripes! If I had known that I would not have a screw loose

[Ozmadman]

Hi all,
It has developed a knocking noise, that seems to come from the engine area. Starts and runs well but I just can't bring myself to ride it as the noise gets louder at 40 -45 mph. Its has baffled everyone I have asked who knows anything about bikes.
John

Hi John
Did you ever discover what this noise was? could you try to describe it as I have a similar noise on my 1960 model 8 350.. it comes in as you are coming up to 40 in top gear(or similar revs in a lower gear) and stays there as long as you keep the speed steady. The 'weight' of the sound is like a medium pitch knocking sound but the consistency is that of a rattle, ie; not regular really. As a guess I would say it sounds like it is coming from the rocker area but I have overhauled them with new rocker sleeves and they were all a good fit with the shafts and bushes with no up and down and the required amount of end float (ie hardly any) the head has new guides and valves. It was re-bored about a 1000 miles ago now, piston is good as are the rings and when I had the barrel off could not detect (by hand) any up and down play at all in the big or small end, oil feed is good to all areas. There is no knocking pulling away hard in a high gear or on the overrun. I thought at first it was some kind of vibration under the tank but I have ruled that out now. I was wondering whether it was the timed breather rattling around that has been mentioned in this thread, any thoughts?

thanks
paul

[1608]

Sounds!! like big end from the symptoms described. Also like to hear an up-date to this problem.

[jonnyboyg]

Hi Paul,

Your engine noise sounds very similar. I did go back and take the primary case off again and the clutch and inner plate to check the timed breather bolt. (hoping it was that) - but no. So I'm still no closer to solving it. As I've now ticked off crank shaft, piston, tappets, clutch, engine mountings, tank mountings - the only thing perhaps - are worn cams. The sound is quite loud though and someone would have to help me understand what sort of noise the cams could make when worn... Not really up for dismantling these as I think I will have to re-do valve timings or am I wrong?

The other option - ride it like I've stolen it until it breaks - then I'll know!

Again - thank you to all that have put forward suggestions - I really do want this bike back to how it was - but I'm still in the dark.

[saltbox alf]

Just re read this thread and I wonder if it's a main bearing, I had this problem on my RE, the main bearing inner race had a small section that had let go on the case hardening, there was no dissernable play but it knocked like fury as you describe your problem. I managed to do a 50odd mile run back to home with it and I somehow think it would have gone further if necessary, however apart it came, dropped in a new race , rebuilt engine,fresh oil and filter etc loverly.

So could be something like that?