Hitchcocks Forum

Greetings all, I would very much appreciate some advice re a 2003 model Sixty 5. This bike has recently come in to my possession and when running makes one hell of a clattering noise. I checked valve clearances and as they were all OK so decided to remove the top end for a look see. All the valve gear including push rods, springs, guides etc. were fine so I then removed the barrel. Bore very good and piston condition fine no detectable play in the con rod just a mm or so side to side (like in an arc).
Having no experience with these bikes are they just that noisy ? my 1952 BSA B31 sounds like a sewing machine by comparison! Any advice very much appreciated; thank you.

Is the noise constant, or it is only on over-run/throttling back?

A loose primary chain can make quite a rattle if the adjuster bolt head is banging against the inside of the inner primary case. Might be worth draining the cases and taking the outer cover off for a look and see if it needs adjusting. Our hosts sell a little rubber cover for the adjuster bolt head to quieten it down if it does flap around, though if it's adjusted properly it shouldn't.

Also a little wear in the cam pinions can make for a rattly engine.

A.

Adrian, many thanks for your reply; the noise is constant with the bike stationary or moving and does not appear to change regardless of load.
A quick poke in the inspection plug on the primary finds the chain with around 1/4 inch slack but I will take your advice and have the cover off for a look. I should add the bike runs fine and pulls well its just so dam noisy ! and really does sound like top end.

Check the nut on the end of the crank on the alternator hasn't slackened off, that can result in a noise like bottom end Armageddon.

Hi, as per previous comment re : alternator nut, also check if the alternator rotor itself is coming apart. It would pay to completely go round the bike and check all nuts. A loose headsteady /petrol tank can also be noisy. Vince

In comparison to a B31 they are pretty noisy.
It's worth checking all the points mentioned but it's often said if are RE is running quietly there's something amiss.

Could well be a chassis rattle.
I might get the tools out and start at one end working your way to t'other checking for tightness and drive chain chain guard clearance paying attentio to rear wheel bearings. Had a rattle on the Flash & a box that I could not find the cause of until the rear wheel bearings finally collapsed!

Thank you everyone for your comments; I will take them all on board and go through the bike stem to stern. Hopefully I can report back after identifying the culprit failing that a good set or ear plugs may help!
I just pray I do not get in a similar situation as I found myself in 40 odd years ago with a rattly BSA A65; mechanic at the old Nelson & Fords shop in Basildon came out with the "Nah mate they all do that" line................shortly before the bottom end decided to dismantle its self at 60mph on the A127 !

In general my Bullets have been "quiet". One other source of excessive noise was badly worn rockers, which were replaced with a set from our host. Problem solved.

There are two other potential sources of the noise you describe. Piston slap is one and this is usually worse when the engine is cold and will quieten to some degree at least as the piston warms up. The other is timing gear backlash and this will get worse - or may even only appear - once the engine is hot.