Moose Racing Power Valve Tuning Kit

[SS109]

So, tonight I was kind of winding down from working on my bike and decided to go through the small box of "junk" that came with it when I bought it. I haven't been back in this box since about the same time. Anyways, I'm going through it and there are various main jets, needles, some factory gaskets and O rings, and then I found something odd. I see this small clear plastic box containing two springs, one red and the other blue, with writing on it that says "Moose Racing Power Valve Tuning Kit". My first thought was that this must be for some other bike and the seller mistakenly included them but hand written on the side they are marked for the KDX200. I started doing some internet searching and came across a few posts talking about these kits ($40-$45 new) and even one mention of them for the KDX. It looks like they were made to tune the KIPS governor by swapping springs. One being weaker (red?) than stock which would open the PV earlier and one stronger (blue?) that stock to open the PV later.

Questions. Has anyone ever even heard of these kits for the KDX? If so, are they sweet to have or are they more trouble than they are worth? Also, if you do have experience with them, which color spring is which? There are no instructions with them and I couldn't find any reference to which color is what. Lastly, here is a pic.

[Julien D]

Nifty! No, I have never seen one for the KDX, but I have seen them for KTM's. I think it'd be worth testing them out and see how they feel. I'd be ok with the PV opening a hair later on mine. A stock KDX might benefit from the valve opening a bit sooner?

[Slick_Nick]

The PV spring is fairly easy to swap out too. Remove the clutch cover, pull the governor, pull it apart and swap springs. I never knew anyone made a kit for the KDX.

Might be worth a try?

[gregp]

Interesting. Is this for an "E" series bike, or an "H" series? I agree with Julien. I would have to try them out! You should be able to set them on a table, rest a weight on them, observe the deflection, and see which one is stiffer. The stiffer one should keep the valve closed longer, producing a more mild power band.

[Julien D]

Should work for E or H, the governor is the same as far as I know.

[the machinist]

If you decide this is more of a pita than it's worth get a hold of me. I have a project that could use these, willing to pay LMK.

[SS109]

Hell, I guess I'll give it shot after I get a little riding time in on the fresh engine. It will only cost me some time and a quart of ATF. I'll dig this thread back up when i do to post my impressions on how it works.

[rbates9]

Do these things still exist?

[KDXGarage]

Wow! What a great find.

[rbates9]

I have no clue about the E but the H has a little bolt with two copper washers that holds a detent for the power valve that can be "adjusted" to get different KIPS action in about thirty seconds so that may be why the Moose springs are not around that much any more. But still a nice find, and maybe more tunable.

[Slick_Nick]

I have no clue about the E but the H has a little bolt with two copper washers that holds a detent for the power valve that can be "adjusted" to get different KIPS action in about thirty seconds so that may be why the Moose springs are not around that much any more. But still a nice find, and maybe more tunable.

Did not know this! Is this detailed in the service manual at all?

[rbates9]

I have no clue about the E but the H has a little bolt with two copper washers that holds a detent for the power valve that can be "adjusted" to get different KIPS action in about thirty seconds so that may be why the Moose springs are not around that much any more. But still a nice find, and maybe more tunable.

Did not know this! Is this detailed in the service manual at all?

gregp had a post about it a while ago. I don't belive that it is in the service manual, but I think it went something like take the ball and spring out and the KIPS will hit harder sooner and if you remove one of the copper washers with the ball and spring installed it will hold out longer and be a bit more mellow. I have tried it with the ball and spring out and it does make a very noticeable difference as to the abruptness of the KIPS coming in. I found that if the ground is loose at all then traction suffers greatly. But it does act like the bike has more go!

Give it a try, it is the screw that goes up into the left side where the gear behind the slotted cover is. Just go easy on the screw. It is hollow and can snap easy if you get to tight.

[cornishwrecker220]

i mostly ride tight single track trails on my 220 some of which take place in the woods & on loose ground. i run with only the 1 copper washer installed, the power valve opends just a tad later which really helps with the traction when things get loose.

[gregp]

rbates9 is correct. You can play with the pre-load on the detent assembly and modify the action of the power valve. More pre-load on the spring (using only one washer) will hold the valve closed longer, and give you a longer, more mellow power band. Removing the ball and spring all together will give you a very snappy power band - better for sand and wide open spaces.
Somewhere, I recall reading that Jeff Fredette was quoted as saying something like "Yea, You can just leave the ball and spring out" - but he is a super talented fast guy...

[bored808]

I saw a moose kit recently on eBay and it piqued my interest.
I was looking at the parts diagram for the H model and I see the shaft in the middle and the spring but I don't see where there is a single ball. I do see an item that has 4 balls in it, is that what people are referring to?
I could find a write up on the procedure.