4Th Generation With Cbr900Rr Forks Question

I read before about a common swap for the vfr with CBR900rr front end. Has anyone done this on their 4th generation? the CBR900rr front forks are a bit shorter by about 1", any compensation needed with the rear shock to maintain a correct geometry?

thanks

I'd go with a 929 or 954 front end, that way you'll get the USD forks and a 17 inch rim. I did a complete 929 front end swap and it was about as straight forward as it sounds, no surprises. It does drop the front end down a touch, which will change the steering geometry, but I'm not knowledgeable on that front since my bike has an aftermarket rear shock and is still in its project phase.

Have you ridden it yet Scott?

Thank you Scottay951. I have a rebuilt CBR900RR front end with a 17" CBR600F3 rim so I don't want to spend on another front end. I guess we'll see how it feels.

They aren't USD but they are 45mm IIRC, so they should have less flex than the original 41mm forks.

Being 1" shorter should lower the front end and effectively steepen the rake, making the steering quicker.

Hopefully you won't have problems with the front cylinders/radiator,tire/fender.

Have you ridden it yet Scott?

I haven't, but I started re-installing the wiring harness a few days ago. School is finishing up this week so I should be able to work on it some more this coming weekend!

Thank you Scottay951. I have a rebuilt CBR900RR front end with a 17" CBR600F3 rim so I don't want to spend on another front end. I guess we'll see how it feels.

That doesn't sound half bad! The F3 rim will help out tremendously when looking for tires. The main reason I did my 929 swap was because my forks were toast from my crash and I found the 929 front end in a local salvage yard for $200. Work with what you have at your disposal, but like Canuck said, check and make sure that you'll have clearance with that new front end.

I read before about a common swap for the vfr with CBR900rr front end. Has anyone done this on their 4th generation? the CBR900rr front forks are a bit shorter by about 1", any compensation needed with the rear shock to maintain a correct geometry?
thanks

I know Kev (kgsmotorcycles) used to have it on his 4th gen and was very happy with it. The geomtry comes very close to stock as the offset is only 5mm off compared to 10mm of later USD forks.

thanks guys, I should have everything installed in a few weeks. I'll definitely check all the clearances.

I read before about a common swap for the vfr with CBR900rr front end. Has anyone done this on their 4th generation? the CBR900rr front forks are a bit shorter by about 1", any compensation needed with the rear shock to maintain a correct geometry?
thanks

I know Kev (kgsmotorcycles) used to have it on his 4th gen and was very happy with it. The geomtry comes very close to stock as the offset is only 5mm off compared to 10mm of later USD forks.

IIRC, I remember him saying he liked the 900RR front better than the USD (maybe 929). Thought part of it was that the frame was designed for conventional forks, and the USD don't flex as much. So the 900RR and 4th gen frame just worked better together, for him. 

U/D forks of say 50mm sit further apart and will cause less steering travel lock to lock, as I've found with my RC51 front end, which is similar to the later CBR954 and other U/D forks in dimensions. You can use an SP1 6 spoke front wheel on those too, which is useful as you may not want a 3 spoke front wheel... SP2 wheel is a lighter 5 spoke, but is more expensive to buy used.

Reduced steering travel is only a pain when moving the bike around and not actually riding. I haven't found any significant problem pootling into a car park and turning into a spot, or doing U turns with feet on the pegs.
 

thanks for all the responses guys. I have had a few back and forth emails with Jamie Daugherty about it because I am also considering one of his 929 rear shocks (great guy and very responsive). His only concern with the shorter front end is an instability created in the front due to the decrease in trail. I am not sure there is any way of bringing the CBR forks to a stock VFR length without an expensive custom job for fork extensions or modified triples. At this point I'll probably just ride it once it's all bolted together and see how it goes.

To increase trail, you can lower the rear (but don't forget that the CBR triples have less offset than your VFR's triples, which tends to increase trail.)  Play around with Tony Foale's suspension kinematics program and see what you come up with.  The demo version of the software lets you do quite a lot--do a search for my post on this subject.

Ciao,

Looking for info which USD+mastercilinder/brake lever+triples will fit on my 4th gen (I search but didnot find what I was looking for)

-without having to change or cut into the front fairing

-re-using the oem front wheel+rotors (keeping cost down)

-limited fabrication (I will find someone to make spacers/turn down a front axle if needed; do not have the tools or skills to do this myself)

For looks primarily I must admit but increased performance a bonus.

With the exchange rate is it is, the JD cartridge internal are too expensive for me (and no gains in the looks department)

Only upsides to USD on our bikes are looks and radial brakes.

Downsides - decreased turn radius, expensive to implement, expensive to replace parts, no brake upgrade if not radial, changing fork seals is a real mother unless you have the right tools which = $$

[image: vfr13.jpg]

Here  go     a  guy  on VFRWorld  has  it for  sale  mite  have  some good  info.http://vfrworld.com/...3-vfr-750&cat=1

Got  to  be  better .
 

I have the 900rr 45mm front forks in my daily ride flush with top yoke and the rsv mille rear shock +5mm on the ride height and have no issues whatsoever.

Great mod well worth for little money!!