31a engine Full circle or T crank ?

[249XUU]

Can anybody enlighten me as to what to expect when changing from standard to full-circle cranks on my 1959 Scottish 250 ?. Will the full circle crank result in a smoother power delivery as a result of more efficient crankcase filling ?. Someone in the club says its horses for courses. My main aim is to make the engine run smoother for general trail riding. As it stands the bike works great through sections but feels rough on the road and detonates at high revs.

[John Wakefield]

I think this has already been covered on this tread
Scottish 250 to 197 conversion!;

http://www.greeves-riders.org.uk/forums/showthread.php?t=2269

[Brian Thompson]

T Cranks vs Full Circle.

Can anybody enlighten me as to what to expect when changing from standard to full-circle cranks on my 1959 Scottish 250 ?. Will the full circle crank result in a smoother power delivery as a result of more efficient crankcase filling ?. Someone in the club says its horses for courses. My main aim is to make the engine run smoother for general trail riding. As it stands the bike works great through sections but feels rough on the road and detonates at high revs.

I've moved this thread to the 'Non-Greeves Engines' section of the forum as the 'Greeves Engines' section is primarily for the later Greeves produced engines. This is the section for Villiers engine (or other manufacturers) topics.

There's a bit more info on the differences between original 'T' cranks and Alpha type 'Full Circle' cranks in the Wood/Carrick 'Villiers Improvements Handbook'. Here's a link to an abridged chapter from the book; http://www.lortim.demon.co.uk/vsih/cranksha.htm

For more info on the book and John Woods website see this thread posted previously in the 'Links and Resources' section of the forum; http://www.greeves-riders.org.uk/for...ead.php?t=2259

Brian.