Disappointed I didn't find this thread until now but better late than never. Thanks for offering guidance to those of us who can't leave well enough alone.
I bought a TTR250 last spring to get back into trail riding & at this point am quite happy with its air-cooled, low-maintenance simplicity. Though it's a bit dated & a bit heavy it's certainly enough for me to get into trouble.
Anyway, I am thinking I would like to upgrade the suspension since it is tired & because the TTR was not sold here in great numbers, options are limited. The front end seems fairly straight forward (pun partially intended) & there is a Racetech re-valve available as well as some documented fork swaps out there. Seems the '06+ YZ forks are the most sought after. I am thinking the USD forks might be a little lighter but don't know.
For the rear, there is also a Racetech re-valve available but other than that, not much out there. I am wondering about fitting a WR/YZ shock to the back & this is where my question comes in.
The suspensions seem very similar to me, shocks seem to be about the same length, orientation, etc. BUT the linkages between the frame, shock & swingarm are backwards from each other, ie; the TTR has the double-link connected to the swingarm & the 3-hole boomerang shaped link connected to the frame. The WR/YZ is the opposite with the double-link connected to the frame.
I am not sure how this affects spring rates, damping, etc. & if it is fool-hardy to try an “as-is”swap or if the TTR should be modded to use the WR/YZ linkage. Not sure of the differences in swingarm length but the TTR has around a 3" shorter wheelbase (55.3) than the WR/YZ (58.1)
OR I could always leave it alone but that wouldn't be much fun.
Thanks again, TD
pics of each: