D1 wide vs narrow stud?

Hello,

I am looking to start my Bantam project, a pre '56 125. I understand that there are two different stud spacings on the D1's , with the later, wider stud type being more desirable.
Is this the case and does it make a big difference?
Also, is there a way to tell which is which, by year of manufacture or engine number (in a situation where I don't have the engine in front of me to measure, ie. ebay)?

Many thanks,

Andy

There are some good web sites hat will help with the identification process, use google as much as possible.
Best to stick with the older sandcast cases, and wide stud. the narrow versions are a pain!
Regards,
Alan

Alan,

Thanks very much for the reply. You are quite right, I found the answer on Google after further searching. Looks like 1955 and beyond had the wider (55mm) stud spacing. Engine numbers DD101 & DDB101 onwards.

http://tradeclassicbikes.co.uk/page74.htm

Just have to find one now!

Cheers,

Andy