As the header really, I am looking for a quadbike front end for my three wheeler project. Not one of the chinese efforts but honda, or yamaha etc,
WOTYERGOT
kIPPER.

Thinking of building one of these?

not really but on the same lines.
I have a piagio 500cc scooter with a front end right off, just join the two together to make a trike.
500cc twist and go, might be fun.
Kipper.

Could be fun!

Is there a weight below which it would not need SVA or whatever?

[Edited on 31/1/09 by Surrey Dave]

If you do not modify the original bike frame (i.e. The vehicle can be easily returned to its original configuration) then this is not classed as 'radically modified' therefore no MSVA is required, probably just an inspection to verify the vehicles new configuration and taxation class.