Re: M21 needs more power -any advise (if my subject not is relevant - please remove
Thanks a lot for all the feed back and the advices. Camshaft design is most likely extremly complicated as the design has to interact with so many unknown factors. Its great to know that touring cams takes in the lower end and gives at higher rpm.
Long induction manifold and mowing the sparkplug are interesting issues with focus on better performance. Normally i would only consider moving the sparkplug due to higher lift of inlet valve.
As i want stick to pre-war parts the only solution for an OHV, would be a M22 engine but at the other hand its also interesting to optimize the sidevalve design. Have to mentioned that The M21 is used for pre-war landrace so no matter what, a B33 or a Gruppo velox conversion is not an option - I have actually never seen a Gruppo velox kit so these are most likelly very very rare.
The current breather system is similar to many other singles (AJS and Matchless competition) so even there might be room for improvement i think i will keep it as it is - at least for now.
Re: M21 needs more power -any advise (if my subject not is relevant - please remove
Thanks for the illustration, nice looking design. In my opinion it was acually not a bad idea to offer OHV conversion kits most sidevale WD motorcycles. However - since its the first time i hear about Gruppo Velox it must be very rare, and due to that - not a big sale succes. I found another picture and even i am not sure, it looks like the rockers are incorporated in the cylinderhead - just like it was at the more modern BSA A65.