Detailed rear shock specs?

[Extent]

My buddy bought a ZX-6R shock for his SV650, but the SV was wrecked before we got a chance to install it so it's just sitting in my garage right now.  It looks like it might just fit right up to the stock mount points (not an exact copy of the stock shock, but I think it will squeeze in) If I can get it fit in I'ld love to use it myself since it is a nitrogen resevoir shock w/ adjustable bound, rebound, and a lockring style preload adjuster.  I started pulling all the information I could find about the two shocks to see if it would be too far off.

Straight off the spring rate for the Kawi looks pretty stiff, but without knowing the stock rates it's hard to say whether that's good or bad.

Other thing that's got me worried is the specs for suspention travel that I found.  Is that traditionally measured as wheel travel, or the true travel of the shock?  And if it's actual shock travel is there any reason to expect major problems from an additionaly 1.8" of travel?  If it's not a relevant measure I'll just remove it from the list.


Yamaha Vision (82)

Overall length : 315mm
Spring rate :
Spring Length :
Piston travel :

Kawasaki ZX-6RR/636 (03-04)

Overall length : 330mm
Spring rate : 540 lb/in
Spring length : 193mm
Piston travel : 54mm

[Lucky]

I don't remember what stops the swing arm, but with the shock on I suspect the shock does, with the shock off, it's probably something in the pivot pin area & hopefully not the driveshaft.  I would worry that too much extention would dammage the dricveshaft & seals.

I doubt it will fit, or you just might have a bike with the rear end jacked up.. how stable will that be?

You might have options of swaping out the stock, an 82 or 83 spring, though

[Superfly]

I do have an aftermarket shock (the one with the resevoir) but I have yet to take it off the other bike and put it in mine!)  I can see if there is any markings that state a Mfr. & Model # on it if anyone is interested.

[Extent]

Ok, it's close, but not as comfy as I wished it to be.  I updated the number charts above to reflect what I've found so far.

The maximum travel of the piston for the ZX6r seems to be about 3mm longer than the Vision shock.  Might be simply solved by placing a spacer behind the bump stop.  Even without any fix this diference may turn out negligible.

Main problem is the 15mm difference in length (measured from the center of the bolts)  There is enough room on the yoke to drill another hole centered about 2cm down from the stock location but even then it is too wide to fit into the recieving mount on the V frame without cutting off the reenforcing washers on the inside of the mount, which I'm not really confident in doing.  What I'm thinking about is perhaps getting an adaptor block machined out of a small chunk of aluminum.  Then it could be set up to have a minimum of change to the rear height (concevably 0 change) and wouldn't require modifying either motorcycle parts.

The bottom of the shock is no problem.  Just needs the hole enlarged by a mm or two and spacers on either side to keep it centered and you could use all Yamaha mounting hardware.


2cm

[Riche]

Extent
Consider these options. If the shock can be rebuilt. Take it apart and add a spacer to restrict its extension by what you need. This was common in the early 80s when people were lowering MX bikes for short track. The large diameter front forks were lowered similarly by adding a spacer to the damping rod to restrict extension. This practice keep rake and trail near or at spec. If the shock can?t be rebuilt. A machine shop can shorten the shock rod by the amount needed and rethread it.
The MX bikes in 1980 and until they changed the swing arm configuration had a similar looking shock. Have you looked into what their lengths are? Those shocks had reservoirs and damping adjustments.