Following is a suggested listing re the subject.
Front End Stages of Improvement:
1 Do nothing.
2 Make sure front end is straight and both sides squared up and parallel.
2 Set sag and adjust rebound adjustment as best possible.
3 Change fork oil to higher grade, not thicker, better quality.
4 Respring to suit your particulars, 919s being notoriously softly sprung.
5 Modify stock internal compression and rebound valving.
6 Fit aftermarket valves, be they Ohlins, Racetech or Traxxion
7 Fit aftermarket cartridges by Traxxion, one leg has external Compression adjustment, the other has external Rebound adjustment.
8 Graft on an upside down fork off another bike, likely an RC51. (some have put on 600 Honda SS front ends, but there seems to be way more interest in RC51 fronts on 919s than anything else on the basis of what I have seen so far on WT)
You might want to consider scrounging for 04 or later forks for the external adjustability they allow for, but it is not mandatory.
My 05 919 is Stage 6. (Racetechs)
Rear End Stages of Improvement.
I'll begin by stating that the 02s & 3s had cruelly hard springs, so unless you are a heavy weight or do nothing but two up riding, that rock hard spring is numero un to do something about.
1 Find a used 04 or later factory shock unit. It has a lighter spring, and some rebound adjustment. You can find buy these for way less than you will pay for an aftermarket rear spring alone. So, if you just want to do a spring change, buy a used 04 or later factory shock unit.
2 Find a used 04 or later factory shock and have it modified by experts. Whether just adding on a better external reservoir with compression adjustment, or going so far as revalving inside, it can be done, and I think it was zaq123 that had such a build done. You need to be very careful about not spending too much money on this approach though. Whoever it was that got it done, had it done for a very good price. Just found the thread for you.
Look for "here it is, my new-old 919 shock", last post 4/13/2010. It was zaq123. See what he got done. You could PM him for more info.
3 Find a used Penske or Ohlins rear unit.
4 Get a custom sprung and set up Penske or Ohlins rear unit.
A Craft a link addition to the factory swing arm and get a custom sprung and set up Penske or Ohlins unit.
B Swap in a another swing arm with a link arrangement and get a custom sprung and set up Penske or Ohlins unit. A few people have done this, I think they have used F3 parts or similar. (some have done this and used a F3 or similar shock as well)
Personally, I'm at Stage 4 with a Penske. I started with a two way, but later had it modified to three way. My Penske came with woefully inadequate low speed compression damping. The suspension builder had a used three way external reservoir handy, so that was incorporated when the shock was redone.
Some people have fitted a F3 shock to their 919. I deliberately did not put it in the above staging sequence, and will so no more on the matter and leave it to those that have done it and know something about it to say something if they want to.
Hopefully you find this of help.
Hey guys, I am looking to improve my suspension on my 03 919. My forks are non adjustable and my spring is OEM SHOWA. I would love to get a ohilns rear shock and maybe some new springs. Any opinions on what I should do? Any ideas welcome