Quick fork oil question

What fork oil should I use in my 07 wr450f for better anti bottoming performance without to much of a harsh ride?

The service manual has all the oil specs in it.

If you are bottoming often, you have probably broken the plastic bottom valve; the weak link on those forks.

Contact Smart Performance Suspension about one of their re-build kits and oil choices.

The service manual has all the oil specs in it.

If you are bottoming often, you have probably broken the plastic bottom valve; the weak link on those forks.

Contact Smart Performance Suspension about one of their re-build kits and oil choices.

these guys? http://www.smartperformanceinc.com/

it takes quite a hit to bottom but when it does its a real hard bang. took her off a 10ft kicker and landed so hard i blew out a fork seal.

Yes. They specialize in making kits for that KYB open bath fork at various price points.

I will shoot them an email thanks

They never got back to me but ive been looking around and the race tech gold valve is supposedly a "night and day" difference. I also got new seals, wipers, bushings, and o-rings! First time these forks have ever been apartImageUploadedByThumper Talk1374621606.111532.jpg

Another question. Do i need any special tools to get the gold valve installed? Also in the manual it just says yamalube s1 for fork oil. How much will i need?

use 5wt oil, and you will need just over 500ml per leg

Oil height is more important than volume, and the RT gold valve instructions tell you how to measure the oil height to the correct way

I have gold valves in my 08 forks, and yes they make a tremendous difference

you will alos find that your forks springs are weak

Yamaha quote 0.46kg/mm, but mine measured 0.41kg/mm - I now have some proper 0.46kg/mm springs in it and this helps as well

You may find that you are struggling for rebound damping if you go to stronger springs - I was.

I revalved the rebound stack, using the table supplied in the RT gold valve kit and now I have my clickers just past mid point, so I am happy

use 5wt oil, and you will need just over 500ml per leg

Oil height is more important than volume, and the RT gold valve instructions tell you how to measure the oil height to the correct way

I have gold valves in my 08 forks, and yes they make a tremendous difference

you will alos find that your forks springs are weak

Yamaha quote 0.46kg/mm, but mine measured 0.41kg/mm - I now have some proper 0.46kg/mm springs in it and this helps as well

You may find that you are struggling for rebound damping if you go to stronger springs - I was.

I revalved the rebound stack, using the table supplied in the RT gold valve kit and now I have my clickers just past mid point, so I am happy

I have my rebound all the way out ( I like my forks real springy ) I am the second owner (bought with 400km on it) and I dont find it too soft and im 6'2" and almost 250lb with all my gear so it may already have stiffer springs. That being said I like to ride my bike favouring to have most of my weight over the rear end and only have a problem with the forks on jumps. I ordered some ipone 5wt fork oil today. only 1l... $20 a bottle! Getting things shipped on the island is slow and expensive :/

At 250lbs the stock springs wouldn't cope!

I'm 200lbs, and my forks used to bottom out with a bang off even the smallest of jumps, so you may well have stronger springs already

Do you not find that the front end washes out in the the turns, with the rebound damping all the way out?

1litre of Oil won't be enough - its something like 600ml per leg, so you're going to be short

Edited by GuyGraham

At 250lbs the stock springs wouldn't cope!

I'm 200lbs, and my forks used to bottom out with a bang off even the smallest of jumps, so you may well have stronger springs already

Do you not find that the front end washes out in the the turns, with the rebound damping all the way out?

1litre of Oil won't be enough - its something like 600ml per leg, so you're going to be short

oh i know.. I was just saying. Il get another bottle ordered tomorrow. Ive never had the front end wash out on me but the back has.

What should i do to get the top nut off? Its peened in a phillips screwdriver type deal. Im still waiting on oil and my gold valves atm. I asked if any special tools were needed and it turns out a damper rod holder was. I managed to get it off with an impactImageUploadedByThumper Talk1375314103.556348.jpg

Carefully file off the the 'peen over' so you are just filing the top of the nut

Use a 14mm hex headed bolt held in a vice, place the base onto the 14mm hex and then undo the nut. Sorted

If you are going to follow the gold Valve instructions (which recomend converting the mid valve to a check plate type arrangement then you will need a cartridge holding tool in order to disassemble the cartridge

I made mine out of some 1 1/4" Id tube, which I filed notches in to, where it locates in the cartridge. Drill a cross hole in the other end of the tube to use a tommy bar

there are some pics on here somewhere if you search

Edited by GuyGraham

Carefully file off the the 'peen over' so you are just filing the top of the nut

Use a 14mm hex headed bolt held in a vice, place the base onto the 14mm hex and then undo the nut. Sorted

If you are going to follow the gold Valve instructions (which recomend converting the mid valve to a check plate type arrangement then you will need a cartridge holding tool in order to disassemble the cartridge

I made mine out of some 1 1/4" Id tube, which I filed notches in to, where it locates in the cartridge. Drill a cross hole in the other end of the tube to use a tommy bar

there are some pics on here somewhere if you search

What is there in "converting the mid valve to a check plate"? and im Not sure why i would need the tool at this point? what has to come apart?

Im guessing that the mid valve is within the cartridge. ImageUploadedByThumper Talk1375382233.472592.jpg.

If so how do i get at it? Does it thread apart from the piece where the spring sits?ImageUploadedByThumper Talk1375382302.620254.jpg

I tried to get apart and it is STUCK. I tried heat and everything. What does this valve do mainly? Just rebound?

Yes its inside the cartridge which is screwed together, and you need the tool if you are going to get it apart

 

Inside the cartridge is the piston with the rebound shim shack on one side and compression shims on the other

The compression shims work in conjunction with the base valve compression shims

The Mid valve compression is for mid and high speed compression damping

RT recommend converting it to a check plate arrangement as it removes another variable and they say that you may foind the fork has too much compression damping if you leave it in - your choice

The RT instructions will explain

 

I'm glad I took mine apart coz the the nut on the mid valve wasn't torqued down fully so wasn't clamping the rebound shims against the valve which explained wHy I hadn't got much rebound damping

 

It will come a apart, as its loctited together so you do need a little bit of heat and brute force

It does indeed screw  together just below where the spring sits

Yes its inside the cartridge which is screwed together, and you need the tool if you are going to get it apart

 

Inside the cartridge is the piston with the rebound shim shack on one side and compression shims on the other

The compression shims work in conjunction with the base valve compression shims

The Mid valve compression is for mid and high speed compression damping

RT recommend converting it to a check plate arrangement as it removes another variable and they say that you may foind the fork has too much compression damping if you leave it in - your choice

The RT instructions will explain

 

I'm glad I took mine apart coz the the nut on the mid valve wasn't torqued down fully so wasn't clamping the rebound shims against the valve which explained wHy I hadn't got much rebound damping

 

It will come a apart, as its loctited together so you do need a little bit of heat and brute force

It does indeed screw  together just below where the spring sits

thanks. Il have to make a tool up. Could I not just clamp the part where the tool would normally be inserted (where the spring sits) it seems to be quite thick.

Noooooooooooooooooo, you'll damage it and its way to tight for that

 

Stick a tommy bar, pointing striaght up, in a vice

Drop Base Valve end of Cartridge onto the above screw driver (through one pair of the hole near the end

Fit 'tool' into the slots where the springs sits - apply a little heat, but not to much as there is a rubber seal in there, to the threaded area and undo with 'tool'

 

Its tight but it will come undone

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