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Tora Coil U-turn service problem...

davenicedavenice Posts: 72
edited March 2012 in MTB workshop & tech
It's taken me a year but I've finally plucked up the courage to service my Tora 302 Coil U-turn forks! They came from a Carrera Kraken - I think about 2006/7 but I'm not certain.

I've taken the lower legs off, removed and cleaned the damper (it's a poploc - the main issue for me is that the poploc had got stuck and wouldn't lock out). It's always been a bit sticky and has needed a bit of help to unlock, but has always locked happily enough up until recently.

The seals and o-rings all looked in great condition so I haven't bothered replacing them (the bike was quite cheap - figured I'd replace them if the fork felt rubbish when I put it back together).

I downloaded the service manual for 2008 which was the oldest I could find. I've put 145cc of 5w fork oil in before the damper unit, as the manual suggested. Seemed like quite a lot of oil, but I went for it anyway!

I then put 15cc of 15w oil in the damper lower leg and 30cc of 15w in coil leg, as the manual suggested, and put the thing back together.

I have a bit of an issue now - I've only got about 20mm of travel in the fork (and pretty much no travel if I use the u-turn knob to winch the spring right in!). On the plus side, though, the rebound damper knob makes a noticeable difference!

The only thing I can think of is that perhaps I've got too much oil in the damper upper leg. Could that cause this problem? I've only got 400ish ccs of oil left so haven't too many opportunities for trial and error! I'm wondering if I don't have 'turnkey' damping, and should be using a different amount of oil as a result?

Can anyone suggest from experience whether:
a) too much oil in the damper could cause on having 20mm of travel
b) any kind of suggestion of the next step if so - shall I try halving the amount of oil or would that be too much? Just looking for a bit of experience to save a few goes round the putting-it-all-back-together boredom!

Thanks in advance!

Dave

Posts

  • try putting the fork upside down over night, usually sorts it out ( I had tora 318s ) seem to remember
    worst moment ever...
    buzzing down twisting single track then.... psssst BANG!!!
  • leafliteleaflite Posts: 1,651
    The lockout is definately off? You definately poured the oils in the right places? Too much oil can reduce available travel but the rockshox figures are usually accurate.
  • davenicedavenice Posts: 72
    Hey,

    Thanks for the replies. Lockout was definitely off - with the lockout on was rock solid wherever I set the u-turn! However I do have a few doubts about the state of the damper. The reason for me originally taking the fork apart was that the lockout knob had got stuck off (and I like to lock out when I'm on tarmac). Also the lockout needs quite a bit of persuading to come off. TBH I think the damper unit will need replacing to fix that.

    I'm pretty confident the issue is in the damper/damper oil area. I took the damper out originally, although I left the rebound damper shaft/piston in. I wonder if some oil could have been left trapped in there somehow?

    Anyway - I siphoned off 25cc of the damper oil tonight and things seem much closer to normal.

    I think I'll look into replacing the damper unit - perhaps with a non-remote lockout or moco or similar. If I do this I'll take the rebound damper piston out.

    Dave
  • supersonicsupersonic Posts: 82,708 Lives Here
    It can be difficult to judge oil levels, as some will be in the rebound assembly.

    If you get erratic rebound or locking issues, try 10ml back in.
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