Anyone out there know if a set of 88-91 RS250 forks (non-upside down), will bolt on to an NSR250 without any modifications?

I want to know if I can use the stock trees, brakes, axle and fender. I want a fork that is better than the SP but I don’t want to bother with fitting an upside down model. I want a true bolt on. They look like they might work.

Thanks,
Chuck

As far as I know, yes. They are a 41mm conventional fork.
As for the fender, brakes and axle, I don't know. But I met a guy in NZ with a set of older (non USD) TZ forks on his NSR. Admittedly, he had swapped the whole front end, wheel, brakes etc. But they worked.
And the RS is a honda...
_________________
The Chopster

I have exactly what you are talking about on my own bike.

The RS forks are 41mm and fit into the clamps, BUT...

-Only the MC21 brakes calipers will bolt right on, and even then, the caliper will hit the disk a tad without a little clearance grinding. It is better to use the RS calipers, but the MC21's will work. MC28's bolt up entirely differently.

-The RS forks are about 20mm shorter than the NSR forks. The NSR fork height sweet spot is 14mm over the top of the triple though, so you would have to run the RS forks about 6mm below the top of the NSR triple to get the same geometry. That is where my forks are now, and I plan to have a little machining done to the top clamp to get the clamp to sit lower and align with the top of the forks.

-The RS triple clamp that corresponds with these forks has a shaft that is dramatically larger than the NSR's. You would need some custom bushings made to fit the NSR stem in there. I have one of these, too, but I think machining the NSR clamp will actually be easier/cheaper for me. I have access to a limited amount of machinery and am on a tight budget.

-You would need the larger RS 298mm disks to line up with the brake caliper location on the RS forks. It is possible that the CBR disks may fit, but I have not verified this. The diameters are the same, but I am not sure about the offset.

- The NSR axle is a tad short for the RS fork setup, but will work. The RS forks are wider on the bottom as they have 2 pinch bolts on each leg instead of 1.

-The front fender mounts on the RS are identical to the MC21.

-I have not verified this, but my eyeball says the seals and bushings are identical to the NSR stuff.

What you get with these forks:

-they are lighter. The forks are not only shorter, but use lighter weight internals. The RS cartridges and damper rods are aluminum while the NSR uses steel. You may want to run a real good synthetic oil and change it more often so your parts last a long time.

-external compression adjustment! Woohooo!!!

-2 pinch bolts on the axle, make the forks a tad more rigid.

-absolutely STONKIN' front brakes!!!!!!

And I run a Coerce fork brace which can only help things even more...

By the way, that fork brace was for the NSR and fits perfect on the RS forks.
_________________
Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS