All you can adjust is the preload. You need a spanner wrench.
http://www.xs650.com/forum/
yes the only difference is the ignitions
With shorter shocks.
The Yamaha 850 XS is an air cooled bike. There is no radiator to fill.
If you are talking about the 1980 Yamaha Enticer, the top speed would be 55mph.
133.6 MPH
On a Yamaha 1980 XS400 the valve clearance for the inlet valve should be 0.0003 inches. The valve clearance for the exhaust should be 0.006 inches.
Suggest you call a Yamaha dealer for info.
20w/50
6.8:1
Mid 1980's
1000
I have a 1983 IT175 Yamaha and the fuel mix is recommended by Yamaha at 28 to 32: 1 I use 30:1 ratio. Hope this helps