2009 yz450f rear shock service?

Just curious, i have 105 hours on my bike and never had shock serviced,

Is there recommended time, when to do that?


If it's never been done, it needs to be.

I think the recommended service interval is 40 hrs. Yep it's time.

Like the other guys have said, it needs to be done. I service my own suspension and have done the forks (both chambers) and shock at 10 hours, 30 hours, 50 hours and I'll do it in 3 hours ride time which will be 70 hours. I used to keep a 30 hour service interval, but noticed such a big difference in feel that I dropped it to every 20 hours. I serviced the suspension at 10 hours just to get the factory oil/fluid out as I'm guessing it's not the best stuff out there, and with the bike being new you'll get a lot of contaminants in the oil from new parts/bushings wearing in.

At any rate, it's time for yours to be done :smirk:

To further add:

It's typically time to change your suspension fluid when it looks more like chocolate milk than oil. I dunno how many hours that works out to.... :rant:

There are numerous videos, and magazine articles out there about how to do this job. It's not as tough as some whould have you think, but do be diligent about it. There is a possibility for real problems if you make a mistake. Visit the "SUSPENSION" forum if you run into areas where you have a question. :p

I guess I would state that I've serviced my own, and my buddys', KTM dual piston WP PDS shocks. The KYB is a piece of cake compared to those KaTooM shocks, as far as bleeding the air out is concerned....... My point here is that with enough info, you can do this job. If a Goob like myself can do it, anyone should be able to. You will likely need to have a shop fill your nitrogen for you.

Here's a link to a good article by Dave J.

Added in EDIT: Czechalien, it's not totally necessary to tear the shock apart as far as Dave does in his instructions. If you're only doing an oil change, I personally would skip the parts where he calls for the compression adjuster removal (steps 12-18, I believe), and where he disassembles the shock shaft/piston/shims (steps 28-38). This is if you have no oil leaking, if your bottom out bumper is in good shape, and if you're not going to change any valving or shims, and when you're ONLY changing your oil. You will need to bleed the air out "conventionally", but I always found that wasn't any real disadvantage..... :smirk:

I also know that it adds an expense, but if it helps to have a visual, the MotoPower videos can be helpful for a guy just wanting to do oil changes. They're kinda pricey (somewhere around $50, I think? :lol: ), but perhaps a you could split the cost with another YZ rider? Personally, I like having as much info available as I can......


Edited by Diesel Goober
Misspelled the word "There". What a dork I am.....

I do my forks, top ends etc. myself, but what about nitrogen?

You can do the whole job using air, then take the shock to have the bladder purged and charged.

I do my forks, top ends etc. myself, but what about nitrogen?

If I'm understanding your question correctly, the nitrogen is in the reservoir. There's typically somewhere around 150 lbs. of pressure in that little reservoir, with a rubber bladder separating the nitrogen chamber from the suspension fluid. There's a Schrader Valve (looks like a tire valve) on the cap on the reservoir that you release the pressure from when you're going to rebuild the shock. After cleaning the shock REALLY WELL, then removing the spring, bleeding the pressure off is typically the next step of disassembly.

Like Grayracer513 said, after you've rebuilt your shock, you can pressurize it with air, just for a "trial" basis. I've actually ran one for a couple of weeks that way, with no ill effects, but nitrogen is more consistent, or stable, I guess you could say. Anyway, have a shop put nitrogen in there for you, after you're happy with your work..... Last time I had that done, I believe it was somewhere around $10 or $15 to have a bike shop do that for me..... It is possible to get a nitrogen bottle and regulator & fittings to charge your own nitro, but for the average guy just doing his own stuff once a year or so, it's not really worth the money & hassle to set yourself up with nitrogen. Now, if you have a suspension biz, that's a whole 'nuther thang.....


Edited by Diesel Goober

There was a good pdf guide in the suspension forum, however there were no pics... Does anyone have a guide with video or pics cause I'd like to see how it's done before I attempt.

The PDF you mentioned is the one Diesel linked to in post 5.

Dave is the one who started doing the reassembly that way, so I doubt you'll see anyone else's video showing it done like that. I can tell you, though, that his way is by far the simplest and most reliable fill and bleed method.

Read that PDF carefully. It's a job that you do have to do right, and one or two parts are a little tricky, but it's just not that hard.

There have been a few updates to the instructions so search around for the latest version. I know I saw one that Dave updated last month. I just did my shock for the first time and the only gotcha was where you remove the compression adapter for the first time. The instructions do warn about some built up pressure and recommend putting a rag over it when you are removing it but WOW! It blew fluid twenty feet across the garage. This was after releasing the nitrogen and is just some built up air pressure.

Create an account or sign in to comment

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

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now