Jump to content
Antigravity Batteries Product Giveaways - ENTER NOW! Read more... ×
Sign in to follow this  

Switching fork oils. Flush or drain and refill?

Recommended Posts

I am servicing the forks on my '07 WR450F. Basically new seals and an oil change. The bike is new to me and although it was very well looked after by the previous owner he can not tell me anything about the fork oil he last used. My problem is that I have read that it is bad to combine different brands of oils in a fork, or anything for that matter. So must I then completely disassemble my forks and thoroughly clean everything or can I simply drain as much as possible out of the fork including the dampening rod assembly and refill with the fresh oil?

Obviously i would prefer not to pull the dampening rod out if possible and i definitely dont want to open up the d/r.

I guess the best option would be to send the forks out for a rebuild, but whats the fun in that?

Also, does anyone know where there is an exploded view of the dampening rod and its guts?

Thanks in advance

Share this post

Link to post
Share on other sites

just remove the cart complete and clean everything well, have a look to see if the big spring is loose on the base valve(well known fault on the wr base valves) then refill with oil, no point in just draining them, if you have them off the bike do the job right is what i say.

Share this post

Link to post
Share on other sites

It definitely is best to do as mog suggests for the reasons he mentions and for the fact that it can be difficult to get all the oil out of the cartridge while it's installed. If you disassemble them from the fork, it's much easier to completely drain them.

If you use a solvent rinse, pump it out as you did the oil, then flush that by pumping in a couple of ounces of your new oil and pumping it back out.

If you aren't going to take it apart, then it depends a bit on the condition of the oil you find in the fork. If it's pretty clean, drain what you can, and flush the rest by circulating 6-7 ounces of new oil and dumping it. If it's dirty, you really should consider pulling it apart, but if you just can't, use some Dexron ATF and pump and dump until it looks clean, then drain as thoroughly as you can and chase it out with your new oil until you can't see red as you drain it. Avoid using solvents in this case, as it is too hard to be sure you get it all out.

Most oils are compatible with each other, but one or two are not, these will usually be labeled "do not mix".

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

  • Similar Content

    • By smokey9lives
      I have a 2003 DRZ (actually a KLX400) and the head tube bearings are shot.  I ordered a new set to install but I'm wondering if anyone has any recommendations on other parts I should replace while I have the front disassembled.  I was thinking about new rubber fork protectors, but are there other things that wear out on the DRZ front ends that you can only get to when disassambled?
      I also broke off a replacement key that I got for the steering lock.  I must have been made of cheap pot-metal.  Should I just remove the whole lock mechanism?
      Any tips or tricks for getting the old bearings out and the new ones in would be welcome!
    • By hondahondo
      A few picks of my winter project.

    • By Luke Hufford
      Hey guys. I recently purchased a 16 yz250x and the first 2 rides i LOVED the suspension. Then the day before a race i reset all my clickers to stock and everything felt like crap. No plushness at all and deflected off everything. I now have a 5.4 shock spring for my 190 pound weight and dialed in sag. Any recommendations on where i should go from here? Right now the fork is 12 out on comp and 15 out on rebound. Shock is 1.75 turns out on hsc, 14 out on lsc, and 18 out on rebound. Any help would be appreciated!
    • By jake gu
      Today we’re going to be talking a little bit about automotive suspensions and how they work to smoothen the ride of your car. There are mainly three purposes of the automotive suspension system. First, they support the  weight of the vehicle. Second, they maintain accurate tire contact with the ground. And third, they absorb any shock that you get through the road when you hit a bump.
      Most modern vehicles come with an independent front suspension. Which means if one wheel hits a bump it does not disturb the other wheel. Nowadays, people use Coil Spring to support the majority of weight in the car. As it has a really good characteristics for absorbing any bumps as you go up and down on the road.
      However Springs aren’t very good at dissipating that energy. In fact that’s why you have the shock absorber. Which is there to smoothen out the ride and make sure the tire maintains contact with the road.
      In modern passenger vehicles the two most popular suspensions are McPherson strut and double wishbone style of suspension. The main advantage of the McPherson strut suspension is that it’s really cheap and simple that’s why a lot of manufacturers are moving towards this design. The double wishbone design allows the wheel to stay perpendicular to the body as it navigates a corner or as it goes over a bump. And that maintains good tire contact patch no matter where the wheel is situated. Another advantage of this design is that it can be made adjustable where you can control the position of upper control arms ball Joints.
      Click to Know More About Ball Joints and other Suspension Components