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Guest BrandonV

Servicing 426 forks, anything I should know?

16 posts in this topic

I am going to service the forks on my 2000 426 this week. I want to replace the fork oil, replace the seals and put the stock springs back in.

I dont have a manual to work from, but I'm sure I'm up to the task.

My only questions are:

-do I need any special tools to accomplish what I mentioned above? (replace oil, seals and springs)

-in what order should I (or must I) tackle this in. I know the oil will go in last, but beyond the obvious, what should I know?

-Any recomendations on brand and weight of oil? I'm about 220# with gear and am an aggressive trail/desert rider.

Thanks.

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Loosen the caps while the forks are still on the bike.

Back out rebound clicker all the way and count clicks and record

When you pull/push the spring down, You'll need a 17mm open end wrench to remove the caps from the threaded rod...(sorry cant remember what it really called).

take the springs out

remove the nut on the threaded rod

take the white plastic piece out

pump the fork several times and dump the oil

pry the dust cover off with a screwdriver very carefully

pop the retaining clip out of the groove (holds the fork seal in)

pull the tubes apart...you can slide them in and out a few time till they pop apart

take the retaining metal piece off of the inner fork tube

Take the slide metal, washer, seal, and dust cover off.

clean everything

install:

Put a piece of plastic over the top of the inner fork tube and lube it with fork oil (to protect the rubber seal from the sharp edge of the tube...you'll see!)...Ive been using ENZO 01 weight with great results.

slide the dust cover, seal, washer, and slide metal on

put the retaining metal piece back on the top of the inner tube

Get your seal driver (make one from 2" pvc pipe...go to motomans site for directions) and seat the slide metal and washer into the groove of the outer tube....

seat you seal with the driver

pop the retaining ring in

seat your dust cover

turn over and compress fork fully

fill to top with oil

pump inner rod more than 10 times with 5" or so strokes...go go too far or you'll suck air

fill fork again...do over

fill fork again and pump outer tube more than 10 times but not further that 5 or so inches

let stand for about 1/2 hour to let bubbles escape

set oil height (i think stock height is 130mm) im 205-210lbs and I set mine at 115mm to help bottoming

reinstall fork innards in opposite order and dont forget to re-set your rebound

Mike

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I was wanting to do the same thing to my bike but I wasn't sure the technical difficulty of performing this task. I can do about anything to my bike but have not messed with suspensions at all. Also I printed off the manual in motoman's website so I have a parts break down. How would you rate the difficulty of this task?

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It's easy. On a scale of 1 to 10, I'd rate it at a 5. First time may take a little while, but after knowing what you're doing, it should take about an hour per fork tube total when changing seals. Just a fluid change...about 30 minutes per fork tube.

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Thanks for the reply Cal. I think that I will give it a go. I got quoted $125 from the local Pro Action guy so I think it will be worth it to try it myself. Thanks Again.

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If you don't have a bonified syphoning tool to remove new fork oil if you overfill the tubes, a regular spray bottle nozzle work real well.It will remove very small amounts of fluid allowing a pretty precise measurement.

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If you don't have a bonified syphoning tool to remove new fork oil if you overfill the tubes, a regular spray bottle nozzle work real well.It will remove very small amounts of fluid allowing a pretty precise measurement.

Yeah, don't buy a suspension suringe. I bought a large suringe for $2.00 at a local CO-OP store. Works great.

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Is it necessary to remove the bottom valve assembly when replacing the seals? I don't have a 14mm hex drive. (allen wrench)

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Is it necessary to remove the bottom valve assembly when replacing the seals? I don't have a 14mm hex drive. (allen wrench)

Nope.

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OK, I know this has been covered in other threads, but what other oil brand/weights do you guys run. Thanks.

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Thank you! that is very nice.

To your knowledge is there any difference between changing seals on the 450 or 426?

Mike88,

I've mostly been reccomended to use Enzo 01 or Yamaha 's 01 fluid. I've been told Enzo is very similiar to the Yamaha brand (or even the same) for less $$.

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In my 426 forks I ran synthetic Mobil 1 ATF (7.5w) as per Jeremy Wilkey's suggestions (MXTech). In my KTM I'm running Honda 5w oil.

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How did the forks feel with the ATF relative to say 5w oil?

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I never did a switch from 5w to ATF. But I've gone from stock oil to ATF in two diff. 426's and like the ATF much better. The forks seemed more consitent through the stroke with the ATF. I would have used ATF in my KTM, but when I revalved them, the suggestion was 5w oil. I think I'm going to revalve my forks again and use ATF this time.

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