• Welcome to the new B.I.R.D. Forum. Please be sure to read the "New Member / New Registered ? Please Read" thread in the Coffee Shop. This contains some important information. To become a full member ( £5.90 a year ) simply click on your user name near the top on the right I hope you enjoy the new site ................ Jaws ( John )

Fork spring length & OE length

silverfox.xx

quocunque jeceris stabit
Having contacted FTR Suspension the suppliers of my WP fork springs, They have confirmed that taking my weight of 13 stone, allowing for 1 stone of bike clothing, allowing for the fact that a good majority of my riding is 2 up with/without luggage.. and preferring a firmer ride when solo, the linear springs of 0.95Nmm, will be most suitable for me on the Blackbird.

And that the 250mm length of spring will not require any alterations to the OE shock..

http://www.ftrsuspension.co.uk/home.htm
 

Wolfie

Is a lunp
Having contacted FTR Suspension the suppliers of my WP fork springs, They have confirmed that taking my weight of 13 stone, allowing for 1 stone of bike clothing, allowing for the fact that a good majority of my riding is 2 up with/without luggage.. and preferring a firmer ride when solo, the linear springs of 0.95Nmm, will be most suitable for me on the Blackbird.

And that the 250mm length of spring will not require any alterations to the OE shock..

http://www.ftrsuspension.co.uk/home.htm

but what about the spacer??
 

Jaws

Corporal CockUp
Staff member
Moderator
Club Sponsor
Ah why a pogo stick John as adding preload doesn't alter the spring rate just the sag or lack of. .
Absolutely spot on and fully agree mate... So many experts suddenly on here I just thought a pogo stick to be appropriate :-0)
 

Jaws

Corporal CockUp
Staff member
Moderator
Club Sponsor
Sadly wolfy I was not including you..... So you still aint an expert LOL :p
 

Wolfie

Is a lunp
Sadly wolfy I was not including you..... So you still aint an expert LOL :p

I feckin well am, lumpy slitherfix and robbo aint so therefore by the power of greyskull i am a feckin expert!!! :bow:
 

silverfox.xx

quocunque jeceris stabit
WP 250mm long 0.95Nmm linear fork springs fitted, I left the extra 17mm as potential preload prior to cutting 17mm off the spring spacers if I felt it necessary. Absolutely fine, static sag is 34mm (Road sports bikes I believe should be between 30/35mm, about 1/3rd of full suspension travel). Handling has been much improved, greatly reduced nose dive, rear now does not come up off the ground during heavy braking, powering out of corners it doesn't drift out but holds line, bumps are considerably smoothed out, Braking hard coming into corners once the brake is released the bike immediately settles as the forks are not still returning to ride position, thereby allowing a smooth transition. Power on mid corner does not unsettle the bike. NB: 6mm rear shock spacer is also fitted.

As the forks were left in place, I sucked out the old fork oil using a piece of tube with wire wrapped around it to keep it stiff, and used a 25ml syringe heatshrink/cable tie attaching it to tube for suction, according to the amount removed most of it came out. Refilled with 10w shock oil.

It was a but awkward holding the spring spacer down (flat blade screwdriver) to allow initial fitment of the fork top nut to the damper rod, due to the 17mm preload being left on, however once started a 14mm spanner held the lock nut/fork tube spacer in place. Assembly was made a little bit more awkward as I have bar raisers fitted, but not frustratingly difficult.

Good news is that the suspension drag (fork seal/linkage) has been reduced from 15mm (OE) to 3mm (new springs) on the front. The back OE is excellent at 0mm drag.

The removed OE springs were on top length of service limit spec, with a static sag (or should I say sog) of 49mm :eek:. Currently rear OE has 55mm static sag :eek:, so that'll be the next thing to do, now the new front has made the back feel very slightly under sprung, as you would expect.
 
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J

joescot18

Guest
Suspension

New Jaws springs and spacers , preload adjusters fitted , 6mm spacer on the back --------------------20mins total bike feels like new , will do the oil when I get a chance ...joe
 

Wolfie

Is a lunp
original springs, no preload, original shock not on max, spring preload as from Honda, new oil in front, also feels fine. 54 000 miles.

all rebuilt 2 years ago. maybe 3 yrs cause they were fecked and you took a dive on a track cause the rear would not let get round.
 
J

joescot18

Guest
I HAVE NO IDEA HOW MUCH STATIC SAG I HAVE ,, ALL I KNOW IS MY ARMS AND SHOULDERS FELT A LOT BETTER ON THE BUMPY ROAD TO WORK ...JOE
 

silverfox.xx

quocunque jeceris stabit
original springs, no preload, original shock not on max, spring preload as from Honda, new oil in front, also feels fine. 54 000 miles.

My fronts were soggy, much too much nose dive under braking.. Even Gina said that the bike felt better without the nose diving trying to flick her up over my head.

Rear shock still seems ok, even if its a little under sprung. Rear preload is up on standard for 2 up riding and rebound up 1/8th. But with 55mm static sag solo the spring is too soft.
 
P

Paddysteel7

Guest
aha

carb air gap is 154mm fluid 486 -+2.5cl spring out honda workshop manuwell

inj air gap is 142mm Fluid 483 -+2.5cl spring out honda workshop manuwell

john says 142 spring in damper out

pete says 83 spring in damper in

book says 142 or 154 spring out damper in

pete says 125mm spring out damper in

john says 184 spring out damper out


all above relate to past measuring of a displacement of 42mm by the spring according to a member of this site(name escapes me )

I would like to know how anyone even john can measure the air gap with the damper out as that is what holds the fork oil in so damper out means no oil?
 
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