Front Suspension Upgrade - FZR

guys a teaser of my doodads - both made and ready to use after tomorrow

Concept is they go down into the spring to make the coils above the grub screw inactive affectively increasing the spring rate.

Last thing left to do is make a weld locator on the upper washer as I can envisage these things wanting to unscrew themselves.

They install by removing the grub screw, inserting the bar into the spring then reinserting the grub screw - then wind through the coils like a thread.

Lock nuts and washers keep the upper end tight and the upper washer goes into the spacer tube to keep the whole unit centred.

Installation & removal takes minutes and I'm only going to use these on a particularly smooth stretch of road adjusting, go for a ride, snatch the brakes and check the dive.

From measurements I've made of the springs I know whereabouts to cut to get the recommended spring rate according to the race tech site. This way however I can test both sides of that spring rate without cutting anything







Shortened springs in conjunction with the emulator valves should get me where I want to be handling wise

 

I reckon they will work - if I could only get the bike to run properly, it played silly buggers with me this afternoon, running on three cylinders and now won't start.

If the spring modifiers make it easy to work out the spring changes I'm happy to post a howto or even post these ones to anyone that wants to give them a go to see if they'd like to increase their spring rates

peace out

 

What was the spec spring rate of the ones they already have?

I'm leaning very much towards the damper rod cartridge emulator valves and single rate springs, which is per the race tech recommendations - still pretending I'm a boy racer it seems...

peace out

 

When I got springs made for the TZR250 I was told that Yamaha springs normally have a smaller diameter end.
The TZR250 has 39mm forks.
The dimensions are:
Original spring length 400mm.
Fork tube inner diameter 33.9mm.
OD in the middle 33.3mm.
One end is OD 32.5mm and ID 24.8mm.
Other end is OD 31.3mm and ID 23.2mm.

I got Accu Products in USA to do me three sets of springs; 0.67 kg, 0.70kg and 0.73 kg for $US110 a set.

The 0.67kg are the ones that worked best for me. But I am 77kg and the bike is <100kg dry.

 

those 0.73 kg/mm ones that you got are about spot on what the calculator on the race tech site recommends for my setup - the race tech ones start at 0.80 kg/mm though

Not sure if they'd go into the fzr forks though, I'll have to check the actual diameter below the fork cap threads.

Which bike were they originally for? - the accu products site only lists GP bikes

 

Accu got them custom made for me.

 

I thought the Ikon prices were a little high, however the lower prices from the US rise to almost the equivalent amount or more once shipping is included

I do like the look of that race tech suspension bible...might have to get myself a paperback copy eventually

 

Bernie Wilber's book is excellent too.
But if you just want a good overview then check this out: http://c-not-k.com/BikeStuff/ShopTalk/Data/SuspensionTuningGuide.pdf

 

prices here make the Ikon ones look pretty good

http://www.suspensionshop.org/JSONViz-Replace-Fork-Springs.php

and

http://www.suspensionshop.org/JSONViz-Springs-Linear.php

$199 - $250 AUD basically

 

Guys a poll to see who's interested in knocking the shipping costs down on some of these

These are derbix emulators - more expensive than the derbix site but the shipping costs from derbix are ~40% again over the cost of the item

http://www.ebay.com.au/itm/V-T-41MM-Fork-Damper-Valves-for-Harley-Davidsons/380860880331

with any luck, we can get say 5 sets for the same shipping cost

Outer diameter on these units is 31mm - they will fit into the upper stanchions of the fzr forks neatly and the diameter of the lower portion which sits into top of the damper rod is 23.8mm.
I will check and verify the damper rod clearance before committing to any purchase so we get something that fits without hassles

Mine is a 3LN1 for reference

peace out

Glenn

 

Come on guys - who would like to split shipping costs on some of these cartridge emulators?

 

Sorry I'm out, I've got too much on my plate at the moment.
I've only got 3 months & Will will be on his blacks & no doubt he'll want an R1 or bigger & Emma will upgrade from the NSR 150 to the Fizzer that he's riding now.
Emm's only about 50 Kg so it'll be perfect for her as it is.

 

C'mon guys who wants to get their suspension working more like a motorbike and less like a rocking horse

 

Anyone amongst you done the Zxr250 front end swap onto a fizzer?

Any pros or cons worth mentioning.

Do the Zxr forks have good damping in stock form and any adjustability to speak of, preload, compression & rebound damping?

peace out

 

zxr forks are completely adjustable im not sure how far either way they go. Have a look in the zxr manual ruckus