A7ss engine clatter

[cableguide]

Hi everyone,

New poster here and long time old biker who's in desperate need of help. Great site by the way..

I rebuilt a 1960 A7SS several years ago, new everything with close attention given to fits where ever possible especially the crank end play etc etc but the thing is there has always been a horrible clatter coming from the engine.

Ive heard this racket on other A series bikes Ive been near,  and Ive also heard bikes which sound smooth and quiet so somethings not right Im sure.

The only thing I can think of which can't be repaired etc is the running fit of the followers in the barrel tubes which definitely had a bit of slop in them, but is this enough to create such a din!

Best I can say is that it does seem to emanate from the barrel area, but the bike doesnt smoke at all and I'm positive the pistons are a correct fit in the bores.   

One thing I have noticed over the years is that the iron head models never appear to have this noise, it always seems to be a bugbear of the alloy head bikes.

All thoughts most appreciated

CG

[muskrat]

 G'day CG, welcome to the forum.
                                             Noise questions are hard if we can't hear it. Crank/piston noise at engine speed, cam/valve noise at 1/2 engine speed. Set up a strobe light to confirm.
My first thought was backlash in the timing gears. Has the cam been reground or a comp plate put under the barrels? Could be a follower dropping onto the locating peg. To eliminate the followers take off the inlet tappet cover and drop in 1/2 cup of oil with a good slurp of lucas oil (that thick stringy oil http://www.lucasoil.com/products/display_products.sd?iid=25&catid=7&loc=show&headTitle=%20-%20Lucas%20Heavy%20Duty%20Oil%20Stabilizer) and start motor. Should quieten them down.
Cheers

[orabanda]

Have you checked tappet clearance?

[cableguide]

Have you checked tappet clearance?

Ora.

Yes done that many times, its a heavier more metallic sound than tappets but it wont hurt to have another check.

Muskrat. I like that idea with the thick oil, worth a try i think.

Thanks to everyone else for all ur informed replies, would be good to get to the bottom of this.
cg

[Rookie_V#60]

Hi,
I have a similar problem. Here some recording of the noise:

http://www.youtube.com/watch?v=4nmUH6xnQpA&feature=youtu.be

The engine has good power, starts good, made a 300 mls run without problems, noise is not louder when hot,....

It is no aluminium head (A7 from 1948) ????

What is it? Piston clatter, cam/tappets, timing gear, big end, primary chain?

Rudolf

[cableguide]

Rookie,

Urs sounds like a single tap something like a loose small end. My bikes not on road so cant record noise but its more of a cacaphony of several loud metallic clangs.