FXR150 fork oil?

[phoenixgtr]

Hey guys.

I dissassembled my forks to get the stanchions straightened and not sure how much oil or what weight oil to put back in. Anyone got any clues as to what would work?

Cheers

[Skunk]

Nothing on www.fxr150.co.nz? Hmmm, just had a look and the answer seems to be 'no'.

[Sideways Sam]

I put 20 in mine initially and it was really stiff which felt good, have gone back to 15 because the guys with softer forks were going faster than us.........

The 20 does help with the nose diving under breaking, these things have really soft front ends......

[phoenixgtr]

Yeah already looked there Skunk, thanks anyway.

15 was about what I was thinking Sideways Sam. I'm only a little guy, so hopefully dive won't be too much of a problem. These forks may have actually been modified too because they were quite stiff before I pulled them apart. Do they normally have progressive springs? i.e. tighter at one end of the spring...

Any idea what volume of oil they take?

Thanks

[Sideways Sam]

They are progressive from the factory, allthough some people chop a bit off the other end which has the effect of stiffening them up a wee bit.

When I drained mine I got 250mls out of each fork which is the same amount I put back in.....

[richban]

Yeah already looked there Skunk, thanks anyway.

15 was about what I was thinking Sideways Sam. I'm only a little guy, so hopefully dive won't be too much of a problem. These forks may have actually been modified too because they were quite stiff before I pulled them apart. Do they normally have progressive springs? i.e. tighter at one end of the spring...

Any idea what volume of oil they take?

Thanks

I am going to service mine and try to get them working a bit better. I found this http://www.strappe.com/suspension.html Has some good simple stuff to try. May help.

Cheers

[speedpro]

Put in the 250ml as suggested then with the springs out and the fork fully compressed measure the distance from the oil to the top of the fork tube. That's the dimension to play with. I've added just enough oil to stop my forks bottoming out in use. You use the oil viscosity to get the rebound damping working like you want and then drill or weld holes in the damper rod to get the compression damping you need. I'm not familiar with the FXR forks but I would be very surprised if you don't need to reduce the size of the compression damping holes in the damper rods. Extra compression damping helps control bike attitude under brakes and also helps with controlling rear wheel lift. I've got emulators in mine and extra 2 turns on the preload more or less sorted the rear wheel lifting problem.

I am most certainly no expert in this matter but I don't think that is "bad" advice.

[Sideways Sam]

Put in the 250ml as suggested then with the springs out and the fork fully compressed measure the distance from the oil to the top of the fork tube. That's the dimension to play with. I've added just enough oil to stop my forks bottoming out in use. You use the oil viscosity to get the rebound damping working like you want and then drill or weld holes in the damper rod to get the compression damping you need. I'm not familiar with the FXR forks but I would be very surprised if you don't need to reduce the size of the compression damping holes in the damper rods. Extra compression damping helps control bike attitude under brakes and also helps with controlling rear wheel lift. I've got emulators in mine and extra 2 turns on the preload more or less sorted the rear wheel lifting problem.

I am most certainly no expert in this matter but I don't think that is "bad" advice.
That's sounds like a pretty good summary of the deal to me.

[phoenixgtr]

Thanks for that Speedpro. It makes sense. I'm not going to attack my damping rods at this point though. I've yet to race the bike and see what the suspension's like on the track

[F5 Dave]

The emulators address the main problem with damper rods. Fixed hole orifice for compression. Like an old door damper they work fine at slowing down a door flying open & then returning. But try & push them too fast & they will lock up as the pressure increases exponentially with velocity.

Hence you can set them up to be pretty good for braking & direction changes, they will not cope with washboard bumps. For the same reason oil viscosity increase runs into the same issue, although if you are lucky the extra heat will break it down after a while reducing the problem.

Ruapuna isn't so bad, but Mt Wgtn just entering the S's in front of the pits clockwise, or the seal change on the left hander going the other way will test them.

[Sideways Sam]

The emulators address the main problem with damper rods. Fixed hole orifice for compression. Like an old door damper they work fine at slowing down a door flying open & then returning. But try & push them too fast & they will lock up as the pressure increases exponentially with velocity.

Hence you can set them up to be pretty good for braking & direction changes, they will not cope with washboard bumps. For the same reason oil viscosity increase runs into the same issue, although if you are lucky the extra heat will break it down after a while reducing the problem.

Ruapuna isn't so bad, but Mt Wgtn just entering the S's in front of the pits clockwise, or the seal change on the left hander going the other way will test them.
Emulators have to be the go. Once you've ridden something with separately adjustable compression/rebound nothing else will do. As soon as I can afford it there'll be a set in my FXR. Gotta pay for a couple of engines first.....

[Pumba]

Gotta pay for a couple of engines first.....

What going to have a spear waiting on the sidelines for a quick engine change between races if Zack blows another one up :clap:

[speedpro]

four stroke riders, you'll never be able to afford emulators.

[Sideways Sam]

What going to have a spear waiting on the sidelines for a quick engine change between races if Zack blows another one up :clap:
That's the plan.

The problem with these spnsored riders (kids) is that they have no idea how much money and work is involved......... Therefore they ring the shit out of everything crash 10 times and hand you back a broken bike at the end of each day.........

One day I'll have a whole spare FXR that he can jump on after he's crashed out on the first lap (or the start line.....)

[F5 Dave]

.........
One day I'll have a whole spare FXR that he can jump on after he's crashed out on the first lap (or the start line.....)


. . .The problem with these spnsored riders (kids) is that they have no idea how much money and work is involved......... Therefore they ring the shit out of everything crash 10 times and hand you back a broken bike at the end of each day.........


Can anyone see the self fufilling destiny part here?<_< Even less consequence

[Sideways Sam]

Can anyone see the self fufilling destiny part here?<_< Even less consequence
You missed your calling as a Shrink..........

Basically it's like this. He rides so damned fast it's worth the effort just so I can watch......... Plus the crashes are a helluva good talking point!