A10 Squealing like a pig!

[Rick Rybicki]

1959 A10, Was a Gold Flash. now has ally head and Spitfire cams.
Starts fine, runs fine but on it's last but one outing, developed a nasty squeal. It goes like this;
Start up, run static for about 30secs-1min, squeal starts from engine area.
Sometimes it starts shortly after setting off.
Clutch has no effect on the squeal.
No excessive smoke from exhaust.
I've only been out on it once since the noise started. Just to test it. Noise started shortly after I set off.
Thought it may be slipping dynamo belt so tightened it....still the same. slackened dynamo belt off completely.....still the same.
Checked oil, it's returning fine. It's fresh oil.
Primary side is "Bob Newby" clutch and belt.
Engine has done about 1500 miles since professional rebuild. Same for gear box.
Suggestions please. Thanks, Rick.

[JulianS]

Could be a bearing or bush spinning in the crankcase or timing cover.

Any bits in the sump?

[Rick Rybicki]

Thanks, I'll check sump tomorrow.
Further info;
Started engine.....no squealing. Revved it for a couple of minuted.....no squealing.
Pulled in clutch.....no squealing. Snicked it into 1st gear, no squealing. Let out clutch to pull away.....Squeal like a pig!
With bike still, pulled in clutch.....squealing, no change. Went through gears, squealing. Back to neutral....squealing.
Switched engine off. Re started engine, no squealing! Switched engine off, swore, kicked tool box......ouch!
Returned to computer.........

Even further info....couple of weeks ago I left the fuel tap on.....ended up with LOTS of petrol in sump. Drained sump, drained oil, put new oil in. It ran fine after the draining and new oil. There were no frightening deposits of metal in the sump at that point.
Cheers, Rick.

[STAR TWIN]

Take a look at your primary belt drive and clutch. Clutches do like to have some oil around, one reason I am sticking to the original primary chain setup. If not a clutch bearing, possibly misalignment of the pulleys. 

[Rick Rybicki]

Thanks, I'll take a look at primary drive side. Pulleys were in line when fitted but something may have worked loose.
I'm puzzled because the noise generally starts when the bike is "Under load" but it doesn't change when the clutch is operated. Sometimes it starts after the engine has been running for a short time with the bike static.?
I'll report back when I locate the problem. Cheers, Rick.

[Rick Rybicki]

OK, clutch centre retaining nut had come loose. Clutch had come loose on the taper shaft. No obvious damage. Surprised the thing was going at all! Going to put it back together with a locking nut arrangement. While I'm at it, gear box is leaking oil, I think from oil seal. I think I can access this if I remove the primary back plate with the gear box still in situ. Is this the case? I've not yet removed the back plate.
Cheers, Rick.

[JulianS]

Remove the primary chaincase and you will expose the gearbox sprocket.

Two possible causes of leaks -

First the large top hat seal behind the sprocket retaimed by a circlip - sometimes dificult to get the new seal in the hole as they seem to be very slighty larger diameter than the original.

Second - oil leaking along the bushes in the sleeve gear, usually worse when bike on the side stand. SRM do a neat sprocket retaining nut which includes an oil seal which sorts this out.

[Rick Rybicki]

Thanks for the info. I will certainly follow up the SRM nut with oil seal.
Cheers, Rick.