I have to say that with all the information I have managed to garner about the M20, the one thing I lament is having an illustrated parts book. I have one, which has no piccys at all, which is not a lot of good when putting it all back together. Anyway, rant over, what I am trying to find out, is whether the barrel is bolted down to the crankcases with spring washers under the nuts or not? Anyone please?

email (option): andrew.honychurch@btinternet.com

Andrew, I use a spring washers,Stainless , ooo arr, as they stop the nuts digging into the ali, cases, I think BSA used plain very thick washers ,but spring ones are imho, just as good, andrew.h.

email (option): warbikes@gmail.com

Hi Andrew,

I found in a bolt and nuts shop, washers which looks plain and thick like the original,
But it is kind of domed. I do not know what is the professional for it.

Anyway, as it is very slightly domed, it give some back pressure as a spring washer would,
looks as the original, and do not open up as some spring washer does when tighten hard.

I use those also for the barrel head.

Noam.

Hi again.

I goggled for “Domed spring washer” and came up with this.

http://seastromwashers.com/SpringWashersSearch.aspx?swt=Dome&AspxAutoDetectCookieSupport=1

What I use looks like the yellowish one.

Noam.

email (option): noam10@gmail.com

Here the nuts and washers as it should be. No real problem with the nuts digging in to the aluminium as they are situated on the cylinder base which is made of cast iron. Not really a standard size washer I think.

Henk.

email (option): ahum@quicknet.nl

down load dragan fly's spares pdf it shows pictures of nuts bolt washers and i think henks cd has spares list on it

email (option): roger.back@node6.com

thanks Guys, as always a great response. I was thinking of putting springs under neath and will do so, but was put off by a motorcycle mate who reckoned that one generally doesnt fit springs where they will get hot, and ergo will lose tension. Anyway, not too bothered by that as they seem to be original fitment, so springs it is. I do have Henks marvellous CD, but still could not find an illustrated parts book. Will try Draganflys, thx once again.

email (option): andrew.honychurch@btinternet.com

loctite as well

email (option): roger.back@node6.com

Hi Noam..In England the washers you describe are known as Belleville washers, after the chap who invented them. As well as a spring washer they can be 'stacked' face to face in multiple pairs to make a spring. I used to use them in that way when making 'blanking' press tools, to return the blanking punch to its start position after punching out a component..Ian

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

Hey Henk, the washers shown in you pic aren't strictly correct, as the are " square/square" spring washers. BSA used " flat/square" spring washers under the cyl. base nuts. These are the type which have a width/height ratio of 2:1.
Cheers, Mick.

email (option): mick@motorbikemike.org.uk

Mick, didn't Nortons just use thick plain washers here ? They don't seem to come loose. Are spring washers necessary ?

Yes Rik, I think you are right, perhaps Norton didn't think their bikes vibrated like others, after all, the didn't think they needed a head steady!
Cheers, Mick.

email (option): mick@motorbikemike.org.uk

Hi Ian,

Thanx for the info.
Always love to read your interesting replies.


Noam.

email (option): noam10@gmail.com