Well for some time now I've been looking to raise the back of my NSR 25mm or so. After hoping to find an adjustable length shock without paying a fortune I'm looking into remaking the triangle pivot plates (shock-swingarm-frame joint) to increase the ride height.

I played with it today flipping the plates into non-standard configurations to feel the effects and seem to have a decent idea what to do.

If anyone has played with this before any help would be great on configuration.

I'll be making some drawings and getting new plates laser cut in about a week or 2 for testing.

you do that for the 18`s to run 17inch wheel if you make it right should work ok. But changing dimensions if you dont know exactly what you doing could ruin the handling

Increasing rear ride height might make the right hand side expansion chamber foul on the swingarm. I've got Tyga pipes and the Ohlins shock which is adjustable for length and the clearance between the swingarm and exhaust is already quite tight without adjusting the length of the shock.

Out of interest; why do you want to increase the rear ride height?
_________________
After years of moaning about immigrants now i am one...

I have the tyga's too and do worry bout them fouling the swing arm. I've dropped the forks a bit into the clamps but the bike still has the feel the rear could get a little higher. Not keep to drop the forks any more. For the cost of some plates im happy to experiment

Please let us know the results when you make the new plates up and try them in the bike.

Is your static sag properly set to suit your body weight? If its sitting down at the back too much it might be worth checking that first to see if the shock could do with more preload.

Have you read this: http://tech.nsr-world.com/nsr/mc18/f3-rear-suspension/
_________________
After years of moaning about immigrants now i am one...

Increasing the ride height by altering the link plates will also alter the suspension's "rising rate", so be careful with what you do. If you must fiddle with that area, do it in very small steps as you could ruin the rear suspension.

A small change in that area can make a big difference.
_________________
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!

yes be careful what you wish for,one of my mates bought an ohlins top of range shock for his zx6r.he and some halfwit messed around with ride height and made it almost dangerous to make it worse they didnt note any settings down the mongs.we had to sort it for him and it took bloody hours,but eventualy worked a treat,but then at 800 odd quid is should have
_________________
ive seen more tarts than mr kipling

More points to be made about increasing the length of the rear suspension;

When we were first putting our MZ race bike together at uni, i went straight down the route of dropping the forks through the yokes and increasing rear ride because i knew these mods would;

Reduce wheel base
Steepen the head angle
Reduce trail

All in the name of quickening steering becuase i'd read in magazines that that is what the top race teams do to their bikes.

The bike shook it bars from side to side when going over bumps and felt a little unpredictable when going from upright to leant over in a corner. It also picked its back wheel off the floor very easily when on the brakes and pitched forwards and back too much when going from brakes to neutral throttle to wide open throttle whilst leaning over which made it harder to judge lines through fast corners with sudden direction changes like Surtees at Brands Indy circuit.

I ended up using shortened rear shocks to drop the rear ride height back down and concentrated on lowering C of G to stop it pitching forward and back so much and also to calm the steering down for better stability.

The moral of the story was that quickening the steering on a bike which weighed in at about 100kg was abit needless as it was already so light that it took no effort at all to change direction fast. It was just a case of making it as rideable and predictable as possible to maximise rider confidence because therein lay the biggest improvement in laptimes. This was only club level racing afterall.
_________________
After years of moaning about immigrants now i am one...

I dropped the front end of my '21 with the standard forks 10mm (HRC base setting is 14mm) and it was great, but it would scrub out (Corsa/soft) front tyres in no time flat. It was a massive improvement over stock though.

I then went to 1990 NF5 RWU forks with an NF5 "gull" top triple. Those forks are significantly better internals, with compression adjustment in the fork bottoms, and rebound adjustment that actually works, but they are [a] significantly shorter, and [b] significantly softer than the NSR forks. With them flush with the top bridge (i.e. with max available ride-height), there was still only about 4" between the fender and the underside of the nose fairing, and on full compression I could just touch the fender against it! The handling was absolutely awesome though, and a few that tried it reckoned it wasn't far behind StephenRC45's F3 in the handling department.

I now have NF5 USD forks on it, and they are leagues ahead of the RWU forks, and also longer. I'm happy to have the steering/ride-height back to a less aggressive level, but it's still dropped from the standard MC21 setup. It's probably close to 10mm again now, like I had it with the SP front-end, but it doesn't scrub tyres like it used to. I also have an MC21 F3 alloy rear shock fitted, with the ride-height set to max, and the whole setup is sweet. Standard link plates used throughout.

All in all, I've personally found the MC21 responds very well to dropping the front a little, but I don't expect it's to everyone's taste. The worst thing was it made the front a lot more planted over crests where previously I would've had the front all light!
_________________
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!

Yeah, on the MZ i first dropped the forks through the yokes to experiment with low C of G versus clearance of the exhaust header off the front wheel. I think i settled on 50mm of stanchion tube showing above the top yoke in the end. Next i took the forks to bits and machined the damper rods down and re-drilled the oil holes slightly smaller to increase damping resistance (just to experiment). I also grinded the springs down to suit. The result of this was that the forks were shorter overall and i could keep my new geometry without having 50mm of stanchion tube sticking up through the top yoke. It also meant that because the fork was shorter overall with less distance between the wheel spindle and the bottom yoke, there was less leverage exerted on it during braking and cornering so it flexed less. It also seemed to ride better too - probably because more of the energy going through the fork was being put into compressing the springs rather than bending the forks.

We next made up a fork brace and made our own top yoke out of aluminium for it. I carried on experimenting with fork oil volume/air gap but the engine fully terminated itself at Silverstone soon after and put an end to the project.

Playing with suspension settings and frame geometry is alot of fun. I'm keen to hear about damo's findings when he tries the new link plates on his bike.
_________________
After years of moaning about immigrants now i am one...