Try this link for the manual http://www.sherco.com/manuals.html and it shows the following settings i.e.mixture screw 3.5 turns out from fully in-then adjust the idle (this would be a starting/base point, I find 3 turns out with 34 pilot jet and needle clip on 4th from top)
290cc
272
76x60
0,0270mm-0,0325mm
1,1 mk/g
98 oct
NGK BP5ES / DENSO W16EP-U
Dell’Orto VHST 28
60
128
33
D36
2ond + 1 clip 0,5
3,5
20mm
3,3
430cc
450cc
SAE 10w40
Multidisco
Digital
2,6 l.
AJP
Ceriani
115 left / 55 right
Sae 5
121mm