what reeds are these?

hey guys, just took my reeds out for the first time and just wondering if anyone knows what kind these are? i compared them to the ones in the RM250 2004 and 2005 manual (I have a 2004 RM250) and they didn't look like the reeds that i have! are these ones stock?

here's some pictures - the last one shows the way they are assembled, from right to left, so the one with the holes in it goes on first, and then is covered by the one with no holes..





They look like Boysen Reeds. And they are not sealing correct. Try turning the top piece over when you put them back together. If there is still a gap, it's time for a new set.

Yep, Boyesen Power reeds. They're pretty good reeds . . . but as tailender mentioned their not sealing. Your reed stops look weird though, like some custom-fab job - usually the stops are thin pieces of flat. I'd order a new set, they're like $35.

ahh would this explain my inconsistent power in the mid-range throttle and rich, sputtering around there too?

i'll see if flipping the top one over seals them correctly. otherwise i'll order in some new ones.

would that be the stock cage with boyesen reeds? i couldn't find any writing on any of the parts

Boyesen power reeds as stated previously. They need to be replaced.

. . . would that be the stock cage with boyesen reeds? i couldn't find any writing on any of the parts

Yes, that's the stock cage.

just flipped over the top reed and it definitely looks better, but it's still not tight against the bottom one, there's a tiny tiny gap that goes away when i press lightly on it.

i think i'll order a new set, get it all nice and tight and completely sealed!

just following up on my previous post: would the reeds being unsealed like they were cause some mid-throttle richness/sputter/jumpiness?

It's definitely possible. The reeds are check valves functionally. Fuel/air leakage backwards would very well impact performance and it could be that at midrange is where the leakage is most prominent. I'd say you'll see gains EVERYWHERE with new, correctly operating reeds.

You may find, however, that with the new reeds you still have that issue which in case you would turn your attention to jetting.

Those look like the power reeds i had in my old yz. Used the stock cage.

The reed stops are removed and replaced with the smaller "rev plate" which allows the reeds to open further at high rpm.

thanks guys, definitely good to know this stuff, i never had a problem with my reeds before so i haven't really learned about them

i'll let you guys know how she runs when i get new reeds and everything else in! definitely going to start with jetting, i was messing with my jetting all summer and wasn't getting anywhere :busted:

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