What are the differences between a YDS1 and 7?
I've read a lot of contradicatory stuff, but even so, the only real changes that I've read about are auto-lube in 63 or 64, and horizontally split cases in the late 60s.
Like chalk and cheese.
YDS1-3 similar with crank mounted clutch, but many differences as developed. All vertically split cases.
YDS5 and 6 a development of 1-3 but with normal clutch +++.
250 YDS series and 350 YR1 series used different engines.
The YDS's were heavy and overengineered. I would suspect they would be limited in their adaption to scambles. Were used with success in Yankee oval/1/2 mile racing.
The Suzuki super six might be a better option. (This is not a super six
)
DS7, like chalk and cheese. A complete new genre with virtually nothing carrying over. Become horizontal split cases and the basis of the RD series that kept the same architecture through to the RZ. DS7 and YR5 shared same engines as did all RD/TZ 250/350's with changes to bore only.