Soft Forks

**Muzzab** · 14th February 2010, 12:10

Seeing as my plan to buy an FXR fell through, back to tinkering with the RX125.

The forks on the RX are as soft as buggery, I figured I'd change the oil and put some
spacers in to stiffen them up a bit.

When I take the tops off the forks what do I find? There is already a couple of spacers
in there. About 10mm worth. I'm going to carry on and change the oil and add another
5mm in and see what it does.

if any one has done this before I'd be interested in knowing how big of a spacer it took before
there was any noticable difference.

Cheers
Muzza

**Kickaha** · 14th February 2010, 12:36

Spacers wont have the effect you're looking for, F5 dave did a very good write up on shortening springs and the effect it has on spring rate somewhere on here (which I can't find at the moment)

**jasonu** · 14th February 2010, 12:53

You will probably need to revalve the damper rods as well.

**Muzzab** · 14th February 2010, 14:56

Thanks for the input. I wouldn't know where to find the damper rods though.

When I drained the oil there was about 90 mls in one side and less in the other.
From what I found on the web there should be 150 mls.

I put 150 mls in them and put them back the way they were. It does feel better.
While I was at it I changed the back shocks to the ones off my parts bike. It feels firmer as well.
I have a new BT39 rear tyre coming, looking forward to getting out and seeing how it goes.
(I'm sure it can't be any worse)

Cheers
Muzza

**F5 Dave** · 15th February 2010, 11:53

Yeah I can't find it either, the new search engine sucks goats. Oil will help esp as gets further compressed as air gap less, but won't do that much earlier on. Stiffer springs are the go, spacers are misleading & do little. Jason is right the damper rods would give better resistance to dive if the hole sizes were reduced, or if you ran thicker oil. On smooth tracks that may be a reasonable compromise.

The problem with both those approaches is that damper rod forks are orifice limited, meaning at some point (like a crude door closer) they get to the speed that no more oil can be forced through the hole so they essentially 'lock up'. This will happen with std size holes but will happen at a slower speed with smaller holes.

Better in my opinion to control dive with springs & then if the rebound needs to be slower consider closing the holes in that side, or just live with it.

**Muzzab** · 15th February 2010, 12:14

Thanks Dave,

I'm sure there is an improvement with the new/more fork oil. Won't know till i get to a track next.
The stuff that came out didn't look too flash. Black and thin.

Cheers
Muzza

**jasonu** · 15th February 2010, 13:00

Originally Posted by F5 Dave

Better in my opinion to control dive with springs & then if the rebound needs to be slower consider closing the holes in that side, or just live with it.

Maybe some USD's from a Ducati Monster or GSXR600 might be the go.
Naa, only an idiot would consider this...