forks are limp

[Black wing]

so ive rebuilt the forks twice now, and i cannot figure out why they will not hold a load, there is 400ml of 15w fork oil and was primed very well. i though it would hold this time but even with the air on high i can bottom out the shocks giving the bike a good shove down. has anyone had this issue? they worked just fine before i replaced the oil seals but i just cannot get them working right now.

 

even the ones on the spare bike i have which were professionally built are more limp and flat than mine

[Freebird]

You say you've had them rebuilt but what did that include? Did you actually replace the springs? If not, they almost certainly need replacing.

[Black wing]

both springs are over 18" and this was not an issue before the oil seals were replaced.

[MiCarl]

The air above the oil is also a spring. If the air space is larger the suspension is softer. It's supposed to be 409ml, not 400, and it may make a difference.

 

For that matter, how much was in there before? Previous owner compensating for weak springs by using excess oil?

[Black wing]

there seemed to be half a litre or more in each fork

[MiCarl]

there seemed to be half a litre or more in each fork

 

There's your answer. Pop for some good springs.

[Snaggletooth]

Yep, at 18" those are stock OEM springs. The Progressives are as long as the stock spring AND the long metal spacer AND a heavier coil.

 

I could drive my old forks to the bottom just by jumping up and down on the pegs before changing to the Progressives. Don't even want to talk about hitting the front brakes hard before the change.

[Black wing]

aright well i got a set of progressives coming in from Old Bike Barn. is the anything i need to know about installing these or is it just a normal install and push like hell to get the cap to screw on.

[Snaggletooth]

Actually you can avoid a lot of the fight putting the fork cap back in. Once the springs are in, cut the spacer so it just comes to the top of the extended tubes, even a little below.

 

As you start the the cap and tighten it the thickness of the cap alone will add a bit of preload.

 

It save the fight. You can always add washers later if you need to boost the preload.