Reed valve performance

Iam running a gilardoni kit on an e50 i have about 200 miles on the bike since the rebuild. I noticed it was running rich so i took off the filter and it was soaked in premix. I was under the impression that the reeds act like a check valve.

With the filter off, the bike ran better but still feels rich, I couldn't get the temp past 320f. is there always some blowback even with reed valves? These are the steel reeds that came with the kit. Could the reeds have worn out already? The spark plug seems like a could handle a tad leaner condition but iam not sure.


Re: Reed valve performance

Douglas Binder /

Wouldn't hurt to change to carbon reeds but there will always be some blow back in a reed intake. At 9000rpm, the reeds are opening and closing 150 times a second.

Re: Reed valve performance

That filter shape and material will clog easily.

Re: Reed valve performance

If this filter sucks this bad I might just try a shampoo air box. For insurance iam gonna switch the reeds.

About the reeds what thickness would you recommend? Also interested in making a dual stage reed setup any tips? I searched some stuff Jbot did but iam thinking it might be more cost effective to buy some already made seeing as I don't think I'll pull it off first try.

Re: Reed valve performance

You can cut cf with sharp scissors.

Buy a sheet and cut em. Can use a mini 1/8 hole punch for the screw holes. Shit even the metal reeds cut with lil scissors. Just sand it well after cutting.

Re: Reed valve performance

those filters are junk, if it hasn't fallen apart it soon will

your plug looks super rich


if youre misfiring/four stroking the engine isn't seeing an even in and out pumping action and you will get more blowback because the rings don't seat right, the cylinder doesn't scavenge right, and you get weird pulsation issues.

Re: Reed valve performance

Now that you mention four stroking; that's exactly what the bike was doing! It would only gain speed if you rocked the throttle back and fourth and if you held it wide open for even a second it produced a noticeable thud.


Do you put any type of filter in the shampoo intakes or just the breather tubes?

Re: Reed valve performance

Overpriced Parts /

I run K & n filters and 8 petal reeds

Re: Reed valve performance

I have a short metal pipe in the end that holds the pipe rigid, and I also stretch a layer of pantyhose over the end, then hose clamp everything together

Re: Reed valve performance

a good filter is good. blowback is still gonna be present with reeds inevitably, stiffer should blowback less, excessive blowback usually indicated worn out or poorly seated reeds but this seems normal. Dunno how often you've gotta clean it but filter needs cleaning sometimes, soak, rinse reoil. That plug looks too rich and too cold. like ready to foul

Re: Reed valve performance

Much love for the tips guys. I ordered a sheet of .3mm reed paper, gonna try my hand at cutting reeds. I'll clean the filter this weekend til I fab an airbox. Then I'll get to the jetting I have main jets, needles and a couple slides and a hotter plug to work with.

The top end is fine for me I don't like revving past 50mph. I generally cruise at 45-50 i would like to see a bit better take off though. iam hoping the reeds help with that.

Re: Reed valve performance

being tuned right is going to help with everything , your engine will literally fight itself to death if you aren't getting proper combustion on every cycle.

fitting new reeds, cutting them yourself, etc... its not hard but if i were you i would really nail down the tuning without changing variables first, then when it runs different with different reeds you will know what changed.

swapping out parts on a bike that is already not running perfecto just adds more weirdness to fight against.

Re: Reed valve performance

Matt Mahloch -- MBM Customs /

Any Puch Gila I’ve ever seen come with carbon reeds. That’s odd yours came with metal. The stock reeds are fantastic.

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