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2009 Evo Suspension Upgrade (For Heavier Riders)

Featured Replies

  • Author

heaver oil, will slow the action down..my local dealer has the 2012 spring sets in stock. if you PM me, ill give you his info.

Thanks, beta uk have them in stock....

You say heavier oil will slow the action Down...... Does this mean firm up the dampening as well ? And also, I'm guessing this will slow down the rebound? Which is to what I want....?

I'll just try the spring first.....

With new heavier springs, if you don't put heavier oil in your damping will be less effective.

Or, change the shims. Oils easier.

Edited by b40rt

  • Author

I've got some putoline hxp 7.5w fork oil.... Was planning on putti that in.....

B40rt, this brings it back to my original question.... Re shims/ tubes etc..... If I were to go that way and lengthen the tube, what material would I use? I've read some folk using PVC waste pipe, but that just don't seem right at all to me.... . .?

What would I use, where would I obtain such a thing ? Hahaha

I understand that the new fork spring and the preload tube should be equal to the length of the old spring and tube..... But I would imagine that the old/ existing spring would have sagged ever so slightly and shortened in lentgth from its original size.... Should this be accommodated for?

I'd also guess that the new spring will be fractionally longer when laid side by side with theold one due to the above mentioned shrinkage.... And this is perhaps why I would need to shorten the pre load tube?

But if I have to use a longer tube, I'm not sure what I would use..... Shortening is a hacksaw job... But Lengthening.... Dunno?

Can anyone explain what the job of the pre load tube is? Is it just to act as something to fill the space between the softest setting of pre load and the top of the spring? Allowing the screwing down of the preload adjuster to communicate with the spring and push it under a load?

One last question..... If I put thicker fork oil in I understand it will slow down the dampening and firm it up, but will it also slow down the rebound speed and make the forks sluggish, or will the new heavier spring compensate for that?

God, I guess the only way to find out is try it..... Was hoping someone else had already been down this route and could offer some first hand advice....

Appreciate your comments guys...

Edited by myzeneye

Hi myzeneye, waste pipe can be bought from any plumbers merchant, or any plumber will have lots of off cuts, if you know any. Springs do shrink with age , so your original spacers might be ok.

Can't say whether your new spring will be a similar length, but the pre-load tube normaly puts the spring under slight tension. The heavier oil should balance out the stronger spring rate, resulting in similar damping .

i would install new springs, and change out to fresh for oil, as it should be changed during maint, and then see if you need more.

take your upgrades one step at a time, or youll chase a tail that cant be caught.

all i did on mine was install new springs, and add Honda Line 7Wt oil, works like a charm, and made a world of differance to the way the bike works,

if you stiil have sag...and i doubt that you will, then add shims ect.

adjust your forks and shock to stock settings, and adjust as needed.

im working on my new{used} 4T that was adjusted poorly the old owner had installed shims, and had the spring adjusted up as far as it would go, as well as all the adjustments turned all the way up..

i removed the junk, installed new springs, and will change the fork oil, when i get to that point, still working on the back half of the bike.

Change springs (Saunders has heavier springs) I changed front on my rev3. 16.9 stones an pebbles. stopped weight pitching forwards so quickly in a turn and made front feel lighter over logs and such. No springs available for back end of rev or I'd change them.

  • Author

Hi myzeneye, waste pipe can be bought from any plumbers merchant, or any plumber will have lots of off cuts, if you know any. Springs do shrink with age , so your original spacers might be ok.

Can't say whether your new spring will be a similar length, but the pre-load tube normaly puts the spring under slight tension. The heavier oil should balance out the stronger spring rate, resulting in similar damping .

Thanks, no problem with pipe, as it happens , I'm a heating engineer ! I just wasn't sure weather the suggestion of using plastic waste pipe was corrector not.... I had assumed they should be some grade of metal ,Alu, steel...etc etc. .....

Thanks for ou advice.... Will be ordering the springs as soon a the shops open again!

Can any one tell me the exact amount of oie I want in each fork leg. ? I'm gonna use the putoline 7.5w I have......

  • 3 weeks later...
  • Author

Just installed my front and rear springs!

Both really simple jobs to do, took ten minutes for each....

Haven't rode the bike yet and have some tweaking of dampening/ preload to fiddle with but already. The bike feels better suited to my weight. (17.5 stone)

I was concerned the 20% rear spring may have been too stiff and presented problems with grip/traction but I don't think this will be the case.... It's still soft and should absorb the terrain well enough without catapulting me into orbit.......... :)

Edited by myzeneye

with 17.5 stone on it i dont think you will have too much trouble finding traction you will bury that tyre :icon_salut:

sorry couldnt resist not far behind you

  • Author
;) it's my advantage strategy..... Get some pies down ye neck quick

I'm NOT much of a trials rider buy have done quite a bit of experimentation in the process of modifying my 2009 4t suspension for trail riding.

My advice would be: Get stiffer springs (by the way increaseing Pre-Load does NOT make a spring stiffer just sets the ride height up higher).

Increase the damping on the rear shock to damp the rebound of the stiffer spring (there is quite a bit of range available). Incresed the viscosity of the oil in the right fork only. This will increase compression damping and provide an increased range of rebound damping to control the stiffer springs.

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