Fork Length - 1990 851 vs. 1996 M900

[dropstharockalot]

Were these front forks the same length? 

I'd like to come up with a direct swap-out for my stock non-adjustable M900 forks that would allow me to not change my brake calipers (40mm mounts) axels, wheels, etc...  The 851 forks seem to fit the bill, but I haven't figured out if the length is the same (or similar... within a couple mm due to adjusters, etc...).

Thanks!

[brad black]

1990 851 has m1r marzocchi forks, but all 1991 onward 851, 888 and 91-97 900ss forks will work.  the axle went from 17 to 20mm around 1994, but that should just be a swap of the threaded bush in the lh fork.  they're all one length, and i'm sure the m900s forks are just the ss ones too.

[Speeddog]

USD fully adjustable forks on a '91 851: Outer legs are ~17 1/8" long, not including the caps and seals.

Same length as a set of forks from a '97 900SS I've got here.

Or just go by what Brad said.