Ok heres the deal. Its an 07 cb900 and i bought it salvage with bent forks. I am after a bolt in replacement and an upgrade. I am aware of the f4i transplant and would like to pursue this route but so far have been unable to find some decently priced f4i forks. There is of course some on ebay but i live in Australia and by the time you pay freight plus exchange rate its starting to get a bit pricey. I am however able to get my hands on some f3 or cbr900 forks very cheap here in oz - hence the questions. If it comes down to it though i will just pay the extra and get the f4i's but i figure if its virtually the same as an f3 fork then whats the point of paying more? Thanks for all your help guys but im still struggling to get a straight answer on the f3/f4 compatability. Ive searched the forums but it appears no one has done this swap so its a bit inconclusive. A search of cbr forums has also proved fruitless... Stay tuned i guess. Will post photos when the bikes all finished!
Would have to check spring rates, travel, fork leg diameter, fork leg length, et cetera, so I can't answer your question directly, would need to do some research. Also, I don't recall anyone else performing the F3 swap.
I totally understand about the cost issue.
The only good news is that it's Honda so you have a fair chance it'll work.
If I get a break here at work, I'll do a little leg work and post back.
The CBR 600 F3 fork stantions are 41mm, not 43, so without 1mm thick adapters they won't work on a 919 / 900 Hornet / cb900f. The first CBR forks that will fit are F4. That's as far as I can go -- I have no information on fender fitment or comparative widths.
If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
------- Rob --------