Guys,
Has anyone used 2005+ inverted forks from a 600RR (or any other bike for that matter) on an F3.
My forks are in pretty awful condition and instead of getting another pair, i would like to have a set of USD's on it.
I cannot buy/return. That is not an available option (geographically challenged).

I would like to keep the stock front wheel/rotors/calipers.

Any help would be hugely appreciated..

 

according to this Fork conversion All ***** Racing
the bearings are the same, not sure about stem length. But if you were to do this you would need the entire 600rr front end.

 

yea they'll fit on the steering neck, but you need THE ENTIRE 600RR front end, the forks are larger in diameter so you need the triple tree off the 600rr, and the triple trees will be wider, requiring the 600rr tire, and the wider tire needs the brakes, blah blah blah... Anyways, I put a complete 954 front end on my f3 last year but never finished the bike...

stock forks-


954 front end-

 

I wouldn't do it.It will drop the C/G too far and make the bike hard to steer.

 

That is actually incorrect it will shorten the wheel base, change the rake and trail, all making the bike steer much easier but be less stable at speeds. If it lowers the front end with this it will steepen the rake and reduce the trail, To mitigate that you can lower the rear. However, I would measure ti difference in height at the center of the top triple tree. The difference will not be drastic and can be corrected with a good suspension set up.

 

My last F3 came with USD forks and the rear dropped to compensate.Bike was hard to turn.Put an F3 front on it and voila,went and won some races in WERA.

 

The rear was lowered that is what made it hard to steer. If you had raised the rear it would make the bike steer in faster. Same reason why people who drag race their bikes lower the bike and extend the rear swingarm; because it lengthens the wheelbase and trail making the bike more stable and track straighter. This is the main reason aftermarket shocks have adjustable ride height.

Also when I say adjust anything on the bike, I mean measured in millimeters not inches for anyone just coming into the conversation.

 

The rear was lowered to match the shorter front end,dropping the C.O.G.,making the bike harder to turn.If one wants to make these bikes easier to turn,there is one adjustment you can do that won't drop the c.o.g. or make the bike unstable.USD forks ain't it.

Failed to mention I changed out the rear shock and link when I installed the F3 front end.It came with the 95-96 F3 link and a short Marzocchi shock.I raised the entire bike back up by installing an 97-98 link with an Ohlins shock,making it proper.The 'Bus Stop' at Road Atlanta was much easier on the shoulders.

 

Installing usd forks is not an adjustment they are parts and just like standard forks they can be adjusted. Like I have repeated and you now state: Lowering the rear end will lengthen the wheelbase and increase the trail and rake numbers, this will change a few handling traits, chief among them the bike will be more stable at speed and slow to respond to steering inputs. Now some of the adjustments to help steer the bike easier and faster are:
Reducing the trail by raising the rear ride height
Raising the fork tubes in the triple clamps
Increasing rear preload
Decreasing front preload

If its hard to flick the bike in chicanes try increasing the center of gravity by raising the rear ride height and lowering the fork tubes in the triple clamps an equal amount.

What Im getting at is that simply installing and swapping pieces doesnt fix the problem, it wasn't the usd forks fault for making it harder for you to steer just like the standard forks did not make you win. Having a proper set-up (regardless of what it is) that was done by a professional suspension mechanic or even yourself if your willing to put the leg work in is what it takes. You provided misleading and incomplete information, I responded. Yes a higher center of gravity will make it easier to turn the bike, the easiest way to raise the center of gravity is to speed up through the turns, it will extend the rear shock, shorten the wheel base and raise the center of gravity, all in one easy motion. If anything putting the standard forks back on gave you more confidence in the bike letting you push yourself harder.

To the O.P. Unfortunately you cannot swap the forks and keep the same calipers because the OEM F3 ones are not radially mounted like the ones on the rr. Also the Rotors are bigger on the rr and the axle is thicker if Im not mistaken which requires a different wheel.

 

I agree with KJohnson! Upside down forks on a F3 for performance are a waste of time and money. Put the money in a rear shock and setting up the stock forks. USD forks are way too stiff for the F3. KJ KNOWS what he is talking about.

Now if you want too look "cool" or make your buddies think the bike is a newer model, or just becuse you want to....then go right ahead. If you decide to, send me your forks. I can use them.