I've just had the stem work finished on my RS front and its gone straight in and its outstanding.
However.
I also had the fork oil and seals changed which means the forks have been disturbed and the settings are all over the place!
Does anyone have any base settings for me to start with?
They came off a 2002 RS250. They are the upside downies with the small compression chambers at the front.
I am 13 stone (plus the leathers)
They have been mounted in a 1992 MC21 SE chassis, All the head bearings are new.
I could also use info on how far down the forks to mount them. I have about 10mm showing at the top of the upper triple clamp.
Thanks.

Do you have the stock forks anywhere?
You can measure the lengths from the axle to the top and compare, then subtract the RS forks from the stock ones, and follow the settings recommended from the NSR-World tuning pages.
If your triples are modified or not stock, then you need to see if they are lower than the stock ... if they are a different offset from the axis of the steering stem then you're going to have to do some more involved geometry calculations.

I've got the old RS250 front end (non-USD) and it is frighteningly shorter. I am going to set it 5mm recessed into the top triple clamp (I.e. -5mm showing) and I'm still going to be 8-9mm shorter than the HRC settings still.

I'm still waiting on somebody pointing me to some frame geometry measurements so that I can make a rake and trail calculator.
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MC28 SE -sold-
MC21 with RS250 engine -for sale-
MC21 race bike -soon for sale-

The stock 18/21/28 forks are 710mm from the centre of the wheel spindle to the top flat surface of the forks. The RVF 400 forks are the same length. What will change the geometry is the amount of static sag you have on the new forks (probably less) but it won't be a huge difference in feeling.

You also need to take into account the rolling radius of your front tyre and yoke offset when calculating the geometry as the rake varies, as does the trail, depending on the combination of the above.
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NSR300R - Why did i ever have a 250...

My experience has noticed that the RS stuff is usually sprung a tad soft for the NSR if you look at the stock spring rates of both. There is a definate ~75 pound difference in weight between the bikes in stock form, dont forget that.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

An excellent point. Is it sufficient simply to wind up the preload? Or do you recommend changing the spring?
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MC28 SE -sold-
MC21 with RS250 engine -for sale-
MC21 race bike -soon for sale-

I have the older RS forks, 41mm conventional. I just slipped in a pair of VTR1000 springs. I dont remember the spring rates off hand, but the VTR rates were right in the ballpark of what I needed, and a bit stiffer than the RS springs that came out. These springs will also work in the NSR stock forks, but you will need a custom length spacer (aka PVC pipe).

With all the diesels out there that switch to stiffer springs and toss their stock ones, I bet you could come up with an easy swap into the inverted RS forks.

That is one reason the NC35 forks work so great. With stock springs, they are set up stiffer than the NSR forks.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

I'm going to look into have a stem made for some forks I'd like to fit on my MC28. Anyone measured the stock stem from top of the lower clamp to the end of the stem?

Woah woah everyone!!!!!
I'm getting one dizzy spell here.
I hope you lot hare having a bit of fun at my expense. Please tell me this is a bit of mischief!
I just wanted to make a few clicks, nip up a couple of clamps and ring it's neck!

Please make it sound as easy as this.