Yet another fork question

[OziOsborne]

Okay okay, I know there are a million fork questions already out there but they were a little vague on answering my question so someone please give me a hand here. I just rebuilt both forks, good as new... except they are so incredibly soft now, even in comparison to before the crash. They look like two pogosticks just bouncing up and down with the least amount of pressure. Asside from all new stock components I upgraded to 15w oil hoping to get a stiffer ride, yet the springs are softer than before. Could it be I either over filled or underfilled the oil level? Aside from rushing in to new springs would it be wise to increase/decrease the oil level to try and get a change and if so what way should I go? Finally, Ive done every adjustment to the heads I could think of (up top where the little screws for the dampening rods are) and I cant figure out which way to go for stiffer springs (Ive never tuned forks before). Do I raise or lower the heads, turn the screws left or right, throw them on the ground and beat them with a mallet... Ive tried everything. Someone should really make a "forks for dummies" manual. Thanks for whatever help I can get.

[richard]

hi ozi,

2 start points,

oil gives the damping action in the fork - otherwise you have fresh air and a spring, so it would seem you need to check the oil level, more oil better upto correct level and then if you over-fill you will have a very hard ride. ( inthe worst case you've got damaged fork internals, or springs in the right way round, etc.)

if you dial in the preload on the fork tops - ie reduce number of lines visible then you compress spring for firmer ride, or show more lines and and you will be 7 years old again on a space hopper

rs

[VeetyR]

it tells you how to setup the forks in the owners manual........Its prob gonna be best for you to return them to factory settings and work from there........

From memory(please correct me if i am wrong someone)....Std Preload adjustment is when the 4th groove on the adjuster is level with the cap......rebound damping is set by turning the top screw clockwise until it stops then anti clockwise until the punch markers line up on the screw and the adjuster..........

once you got it std you can then adjust to suit your needs.

I will check my manual tonight confirm wot i have said above if no one else does.

VeetyR

[Stormin Ben]

Someone should really make a "forks for dummies" manual. Thanks for whatever help I can get.

You mean like this one?

1) Set forks with 5mm more pull through the top yoke than standard ie lower the bike down the fork legs by 5mm (MAX 7.5mm)
2) Set Rebound fully off (screw all way out)
3) Set Preload fully off (all way out)
4) Raise front of bike off the ground and measure from fork seal to underside of bottom yoke. (This is Full Travel) = A
THIS CAN BE DONE BY TILTING THE BIKE OVER ON THE SIDESTAND
5) Return bike to floor
6) Push down firmly and allow to return steadily (do not bounce) - measure = B
7) Lift up with clip-ons (keep wheel on the ground) and allow to settle down (not crash down) - measure = C
8 ) Measurement B+C divided by 2 = D
9) Measurement A minus D = 28mm - 30mm
10) Wind pre-load in until this figure is achieved, keep repeating 6 to 9 until it is correct.
11) Set rebound to "fastest possible return, but under control” (screw fully in & than back out probably ¾ to 1¼ turns out)

Rear Sag
It is important that the rear sag is 8mm. Measure from underside of rear subframe to wheel spindle
1) Take all the rebound off
2) Push firmly down on seat and allow to return. (Do not bounce) -- Measure
3) Hold rear subframe and lift to "top out" the shock -- Measure. This should be + 8mm greater than measurement 1)
4) Adjust until it is.
5) Set rebound to "fastest possible return, but under control"
THE 8mm WILL NOT BE POSSIBLE IF YOU ARE RUNNING STANDARD SHOCK. FOR YOUR WEIGHT PLEASE SET STANDARD SHOCK ON LEVEL 1. LEVEL 2 FOR TRACK DAYS

If you aren't getting any damping action even with teh correct amount of 15W (heavier) oil its possible you've got an airlock in the damping component
To remove it you will need to remove the fork, take out the spring and slowly pump the slider and the rebound rod (pokey up pit in the middle) through its full range of movement a few times
The full method is in the haynes manual I think

WRT basic suspension terms I've written this in the past

Simple guide

Preload - use a spanner on the two flats on top of the forks or a C spanner on the collar on top of the spring on the rear shock
If a spring is rated at 10kg per cm that means it takes a force of 10kg to compress the spring 1cm.
If you shorten the spring by 1cm (using the preload adjusters, screw IN clockwise to INCREASE preload) then to compress the spring a further centimetre will require a force of 20kg coz 10kg will only bring it to the point that the preload adjusters are initially holding it
This is why when you increase the preload the suspension sits higher
HOWEVER
If the spring is too soft increasing the preload is only gonna make it feel better for the first few cm of its travel. After that its back to the same 10kg for 1cm ratio

Damping
When the suspension moves, the oil below the piston is displaced and has to move past it. To do this the suspension has a hole to allow the oil to flow through. If the hole is small the oil can't flow through it very fast and it resists the suspension movement.
This is damping
As you increase the damping you are effectively reducing the size of the hole and the suspension feels stiffer


Compression- not available on standard Storm suspension
when you hit a bump or brake, the forks compress. If you have lots of compression damping this movement is slowed down and vice versa

Rebound - little screw on top of the forks or at bottow right side of the shock
Once you release the brakes of pass over the bump the suspension tries to rebound to its original position. The resistance to this is called rebound damping. If you have lots of rebound damping the forks return very slowly and you run the risk that they may not be back to normal length when you hit the next bump. Conversely if there's not enough rebound damping the forks spring back too quickly. This transfers weight to abruptly and unsettles the bike

[OziOsborne]

Ha, I new you guys were pretty good on this forum. Now that I have a better idea of the tuning process I guess its time for the slow and painful part of adjusting and testing over and over again. Thanks for all the help guys, the more problems I get fixed the more I like my storm all over again.