After hauling thru previous posts it looks as though these shocks were not interchangeable. I have measured them and all seems the same apart from the length. 302mm for the MC21 versus 284mm for the MC18. Is this the only problem?

On the face of it adding more ride height to the MC18 is a good thing but does 18mm at the shock simply push it too far? Or does it end up fouling the frame or linkage.

I guess if I swap to a 17inch rear the whole thing might balance out somehow.

Any thoughts?

I have to laugh sometimes, or I`ll probably break down and cry!

You have the parts there, why not TRY IT?!

You ge the chance to be one of the ones that can tell someone then!

I know - StephenRC45`s got an MC18 and an MC21 - maybe he can take his bikes apart and try it, and then give us all the answer - or maybe Fontyyy - he`s got one of each too!

Sheesh!
_________________

There`s no cure for stupidity… but with the endless supply of stupid people around me, I must be close to finding it!

The Lizard tells it like it is!

Read - Learn - Post... not - Post - Learn - Edit!

Vampire?

Gee thanks lizard I never thought of that.....

Maybe be we could restrict this to people who actually have something to contribute

How much is a very nice condition MC18 SP shock worth to you?
_________________
If I have to take the carbs off once more...

Stephen
not a lot to me but have a mate building up an MC18 R6 . What do you want for it?

This is a pic of the MC18R5 standard shock next to the MC18R6 (SP) shock with the MC21SP shock to the right



By the look of it the MC21 SP shock is just longer in the body and my shock guys says theres a good chance he can cut the MC21SP shock down to suit.

Much shorter hose to the reservoir for the MC18

Planning on a rebuild anyway so may look at the spring as well.

This is a pic of the MC18 linkage versus the MC21 (MC18 top)



I had thought there might be a chance the MC21 shock would fit into the MC18 with the MC21 linkage but no go. The link arm may be useful in raising the rideheight as the 21 arm looks to be approx 10mm shorter. Will measure the effect shortly

This I found on Yahoo Japan...looks very achieveable so will try this to compensate for the 17inch rear and give some extra tuning. Pic is a little off as the standard MC18 linkarm is 110mm.

Just had a measure and 10mm shorter (MC21) on the linkage arm lifts the rear 40mm! Almost too much for the sidestand. So this pic of the adjuster may be designed for racing an MC21.

your going to trust that little screw thing to hold your rear linkage together

Probably end up more like this one



Doesnt look like the other one will work into 100-110mm

This was designed for an RG400/500 and seems to handle the stress so far.
The RG compresses this link and from looking at the NSR, compressing the rear suspension pulls on this link, so maybe not so critical and slightly less weight as well (132kg? versus 154)

would it work if you used the 21 plates with the 18 link arm???
early fireblade uses a similar set up, have you looked at the plates and arms for that??
also you could rotate the plates to see if you could achieve a better balance??

Call me crazy, but I'd just make a set of HRC-spec link plates, as in the Tech Resources section.
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

Not enough flexibility Andy. If you accept the need to lift the rear of an MC18 as standard and are contemplating a swap to 17inch rubber, I assume the plates offer no allowance for both. What was it designed for? A 17inch wheel swap, a useful lift in the rear for track use, or both?

Dunkenb the 21 plates are just too shallow to compensate for the shock length

We have tried rotating the plates in the track bike and gained 10mm from memory which dosen't sound like much but felt like quite a bit on the bike. Not enough here to help with the wheel swap.

I think the easiest thing would be to put the 100mm (ie 10mm shorter) linkage arm in and take the extra rideheight after the 17 goes in as ballpark. If the arm adds 40mm and the 17inch wheel swap drops this by approx half of 27mm that gives a 26mm increase at the rear and there are plenty for sale thru Yahoo Japan. This is measured from the very end of the swingarm to the bungy hooks. Perhaps 26mm is too much, haven't tried it yet.

Its a simple thing for an engineering company to thread some Hex rod (although its a reverse thread at one end) and then buy some rod ends to suit. Thats all the adjuster is although it would be equally easy for them to make the plates I guess

could you cut the standard rod for the 18 in half and insert threaded hex rod into the middle of the too halves?

No the arm is only 10mm thick and the the rod ends use a 10mm thread.

It would theoretically be great to use rod ends with a 12mm thread for extra strength but its impossible to find a rod end with a 10mm bolt hole for the frame mounting and a 12mm thread. They all seem to match mounting bore size with the thread size.

hmmm running out of ideas now.
how about making the plates outta steel and having various shock mount holes in them to vary shock position??

OK, well I have started to develop a two dimensional model of the NSR250 frame/suspension geometry (MC18, for now). The idea being that you will be able to vary the length of the link rod, and change the shape of the link plate in order to get a good idea of what the differences will be. This just saves having to make bits up and blindly just try them in order to see what happens.

Not everyones "cup of tea" I am sure, but hopefully it will grab the interest of a few of you out there. For now you can see a crude pic of what I am talking about at my blog here *edit* And now I've put a pic below as well.

To make it accessible to everyone, I have used a Free 2D CAD package called "Solid Edge 2D Drafting". I am not sure how I am going to make the NSR geometry file accessible to everyone just yet, but I'm sure I can do it through the forum somehow. And NO, I am not trying to sell/advertise a product here. Just trying to get an understanding of the NSR geometry, and bike geometries in general actually.

Below you can find instructions on how to get the 2D CAD application up and running on your PC running Windows. Sorry, not a goer on Linux or mac etc.

I will hopefully post again soon with the file I have created showing the geometry. It is a work in progress, but I hope to get it accurate and functional.
And hopefully, I will soon know what is required to get an MC21 shock into an MC18 (or vice-versa) without upsetting the original geometry
And yes,.. I know,.. the dimensions are not yet correct. It is a work in progress.

I think I've just found a way to share the NSR Geometry 2D CAD file online.
Click here to download it from KeepAndShare.com. Open to any suggestions here.


To get a free 2D CAD package for your PC running a Windows Operating system, either:
ONE:
Go to
2D CAD Package via form
Click on:
Step 1 - Tell us who you are.
• I'm a new user and want Solid Edge Drafting for FREE


fill out the form and download the free 2D CAD package

Or
TWO:
to (hopefully?) bypass the form and get straight to the download go to this link:
2D CAD Package direct

The file I downloaded was 376 Megabytes and called “SE2DDraftV102ENGLISH.exe” at 5/April/2010. So quite a large file.
When installing, the application asks for Name, Business and an optional license file. Just ignore the license file option and click “Next”
Once it has installed, run it and open/create files you are interested in.
There is a built in tutorial that is good to work through, just to get yourself up to speed with the use of the application. As can be expected, learning to use a 2D CAD application can take a bit of time, and cause a bit of frustration.