Hi all

Took my new (to me) MW20 out today for a quick run. It ran fine, did around 15 miles. Pulling back into the drive it suddenly started to make a loud squealling noise that seems to be coming from the left side of the engine (like a slipping fan belt). I pulled in the decompression lever and put her back in the garage.

Any idea whats wrong ? The kick start turns the engine over fine.

Bit worried, hope i havnt bust her !

Ant

email (option): antkenmare@gmail.com

Hi Ant

Unscrew the large plug in the primary chain case, then you should be able to feel the chain, see if its tight.

Rob

email (option): robmiller11(a)yahoo.co.uk

Hi Rob

Thanks, just checked it and its not tight. There is one spot that is tighter than others but i wouldnt say it was tight, can still move it 1/4 inch.

Anything else i should check ?

Thanks

Ant

email (option): antkenmare@gmail.com

Check to see whether the engine shock absorber nut hasn't undone.

Might it be the magneto bolt has come loose and the mag is moving out of line a bit? Pal of mine had this problem, it was not obvious slack loose. We finally located it by tweaking the unit with a screwdriver between the mag and the cylinder and that took the play up - silence. No real obvious movement but enough to make a right yowl.

Thanks guys

So from what you all are saying its something out of alignment rather than an engine problem. Its a relatively new motor so im a little paranoid

email (option): Antkenmare@gmail.com

Whilst the chain case is off check the chain alignment as any untruth may be caused by the hardened steel spacer behind the engine sprocket eroding thus causing the sprocket to tighten up against the crankcase. This condition normally caused by a pattern spacer which is not so hard begins with a noise before locking up but fortunately no real damage is effected so replacement with a quality spare results in happiness and contentment.

email (option): richard177smith@btinternet.com

that happened to me ended up it was the clutch ???

Thanks all

So i removed the primary case and although not dropping off the engine nut was loose. There doesnt seem to be a lock washer or split pin etc. Should there be ? I was thinking about cleaning the wole lot up and then blue loctiting the nut. What do you guys do ??

Hopefully its this causing the squeal, i presume by taking the front sprocket alignment out ??

Cheers

Ant

email (option): Antkenmare@gmail.com

I suggest you also check the dynamo. My friend has a squeezing noise recently and then the engine ceased up. Turned out it was the dynamo and not the engine. JT

Usually if that nut is loose you will lose drive to the clutch as the cush drive lobes will spin over each other creating a loud rattle rather than a squeal.

We had a thread recently about it, you might want to read through it. Ron

http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1379500&cmd=show

email (option): ronpier@talk21.com

Really appreciate the help. Im trying to diagnose the problem in between running up and down the country for work - you know how it is !

So tonight i tried to kick her over again and sidnt even get her started and noticed the squeal. This time with the primary cover off i reasiled it was coming from the clutch basket. I can move itup, down and latetally by a good couple of mm That cant be right can it ? Also noticed the kick starter stiffening up when trying to start ???

Steep learing curve this one

email (option): Antkenmare@gmail.com

Watch or feel the rear drive sprocket.
If it moves up & down with the clutch then you have an internal bearing failure inside the box
If just the clutch is moving up and down then the sleeve gear bush is kaput.
The squeal is steel to steel contact between the mainshaft & the sleeve gear.

To fix it properly it is a gearbox out job.
Go to the technical section & download the excellent notes on gearbox overhauls.

email (option): bsansw1@tpg.com.au

Sorry all im still struggling !

Have removed the full clutch and there is no play in the clutch sleeve. Should my next course of action be to replace the 22 no roller bearings and see if that improves matters ? How are the roller bearings lubricated ?

Thanks

Ant

email (option): antkenmare@gmail.com

It can't hurt to replace the 1/4 x 1/4 rollers. Grease them well which also sticks them in place for assembly and make sure none have tipped over on their side. some oil from the chain will find it's way onto them after that. Ron

email (option): ronpier@talk21.com

Thanks Ron

Many of the web sites I have seen offer roller bearings that are 1/4 x 5/16 for the M20. Will these work just as well ?

Ant

email (option): antkenmare@gmail.com

Have you checked the size you have. As far as I can remember #26-650 are 1/4 x 1/4. If you have the wrong size fitted? It could be your problem.

This seller lists genuine Hoffman's but only 18. You could ask him for a set of 22.
Or ask our own Darren Wrudd from this forum who can also supply them.

http://www.ebay.co.uk/itm/BSA-A7-A10-C10L-C11G-C12-CLUTCH-ROLLER-BEARINGS-26-650-/282404364791?hash=item41c09ca1f7:m:mhWOT76FvJhKz14-o8Jw45Q

Ron

email (option): ronpier@talk21.com

Clutch rollers are 1/4" x 1/4"..(22)...Big end rollers are 1/4" x 5/16"..Ian

email (option): ian@wright52.plus.com

email (option): antkenmare@gmail.com

Hi ant

I had wanted to reply sooner but work interfered

I also had a squeal from my bike last year before I took the bike back to Ireland for a trip

It was loud & very noticeable kicking the bike over slowly

I identified it as coming from the magdyno & it was the magneto bearing on the drive side - degreased after exposure to fuel drip over time - I did have a flooding issue at one point which clearly didn't help

Not wanting to strip the mag before I went - I took a risk - disconnected the Dynamo & ran with it still in place but not driven

Immediately the squeal disappeared - problem solved temporarily - once back the mag was stripped & bearings cleaned & regressed

Dyno back in position & bike running well & considerably quieter

Try it - it's takes a few minutes to ascertain if that's the problem area

Best regards

Job

email (option): Jonnyob1@googlemail.com

I'm afraid that this thread title makes me think of 'Deliverance'..

'Squeal like a pig, Boy !'

Great movie that

email (option): Jonnyob1@googlemail.com

You have to establish if the squeal happens whilst the vehicle is static or in motion. If just in motion you may want to look at the back wheel. I once had a M21 with a crinkle rear hub. The screech came from the hub spinning and the rim not....

Not overloading your panniers like this?............

email (option): fergusanckorn@icloud.com

That lot would certainly produce a loud squeal... ..Ian

email (option): ian@wright52.plus.com

The bike's a basket case.

Ha - cheered me right up that has !

The saga continues im afraid. I now have two sets of roller bearings 1/4 by 1/4 and 1/4 x 5/16. When fitted the 1/4 by 1/4 cause slop in the clutch basket , perhaps 4-5 mm (no slop in the sleeve etc). When fitted with the 1/4 by 5/16 rollers the whole thing feels great , very little slop and rolls really nicely.

I am debating whether to put it all back with the 5/16 rollers or not ? Can I do any damage if I do ?

Cheers and thanks for the continued support

Ant

email (option): antkenmare@gmail.com

I would say that unless you have loads of previous wear, you must be clamping the rollers between the clutch sleeve and the clutch centre, which to my mind means the rollers can't turn and your clutch basket is just skidding round on the rollers. I'm sure BSA used 1/4 x 1/4 rollers for a reason. Ron

email (option): ronpier@talk21.com

Sooooo..

Clutch back in and no noise !!

However it seems the majority of the noise was coming from the engine nut; i couldnt isolate it cos of the clutch noise.

Stripped the cush drive to find there is no spacer or washer behind the sleeve and sprocket. Can anyone show me what these should look like? I think the sleeve has been rubbing against the engine.

Ant

email (option): Antkenmare@gmail.com

I've seen this old chestnut before. The cush drive splined part #56 has a spacer between the outer main bearing shield #109 and crankcase to keep #56 just clear of the crankcase. For some reason, some have the spacer as part of the sleeve and some have it as a separate ring. As I can't see the ring spacer in this wartime parts list, I can only assume it was a later variation. I haven't got one off to measure (maybe someone else has). But you just need to make a spacer ring that's a sliding fit on the shaft and a clearance fit in the crankcase and long enough to just clear the crankcase. I'm guessing from memory...it's about 1/4". Ron

Although at a second look of the drawing. I can't figure out what #116 is. It's not listed in the text, but might be the spacer??

email (option): ronpier@talk21.com

Yes, you can make the ring from a worn 1" distance spacer which goes between the two bearings on that same shaft.

Choose the length so that the engine sprocket lines up with the clutch sprocket.

Cheers, Michiel

Ok thanks guys.

My crankcase seems to have a lip the same diameter as the back of the sleeve. Is that wear due to the spacer not being there or is there a lip grom new. Yrying to understand if i have done any serious damage. Thanks

email (option): Antkenmare@gmail.com

Here, is hopefully a photo of the damage ...

email (option): antkenmare@gmail.com

That's a wear groove and hence your squeal I'd say. I can't think that it will do any harm once you correct the spacer issue. It would be a major job to weld it, you could tidy it if you're bothered with some 2 pk plastic metal of some type. Ron

email (option): ronpier@talk21.com

Many crankcases are worn here...Just clean the damage up with emery cloth, give it a good clean afterwards and then refit all the parts with the additional spacer...

The 'spacer' machined as part of the engine sprocket carrier is the better option IMO as the whole thing is hardened thus reducing the chance of wear...

The separate spacers, which are not hardened, can develop a burr round the edge due to wear over time...

For that reason don't make the outside diameter of the spacer too close a fit into the crankcase recess, as if it does wear the resulting burr can contact the crankcase making it very difficult to get the spacer out at a later date...(and I've seen an engine that 'seized' due to the spacer becoming totally stuck)

I leave about .080" clearance over the diameter (.040" a side) and also put a slight chamfer on the edges of the spacer....Make the spacer I.D. a close sliding fit on the mainshaft...

If you have access to it you can prevent the chance of any further problems by making the spacer from flame hardening 'silver steel', hardening it after machining.. Harden it by heating it slowly to red and quenching immediately in cold water...Ian

email (option): ian@wright52.plus.com

There seems to be two 113s in the diagram.The main driveshaft is 113 &a component next to the shock absorber nut is also 113. Its not April fool,honest.

If you enlarge the drawing enough you can see that the part by the shock absorber nut is actually (a not very well printed) 116....

That's the part Ron was referring to...As there aren't any parts in that location it probably is the spacer under discussion...

Somebody should send a telegram to the BSA drawing office and complain about the number and the location... ...Ian

email (option): ian@wright52.plus.com

Thanks all

I have managed to source a new sleeve with the 'spacer' attached.

Thanks for the support

Ant

email (option): antkenmare@gmil.com