Reeds Limit RPM

So about 10,000 rpm is max speed for any reed valve setup ? The reeds must flutter like the dickens at that rate ! Thus limiting their ability to seal . And do their job , so anyone have any other opinion on the matter . Anyone running a reed setup with a tachometer that rips beyond the 10,000 rpm mark ?

Re: Reeds Limit RPM

i know for a fact that some of the old school 50cc race bikes had reed valves and ran to 18,000

Re: Reeds Limit RPM

yes some reeds do restrict rpm but thinner reeds fix that problem.

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thicker reeds will make the top rpm better since they can flap back faster and won't flutter. they also last longer than thin ones.

so thin reeds do limit rpm but thick ones will not. also boysen dual stage reeds have both thick and thin sets to broaden the powerband.

reeds are another thing that ppl set and forget but they need to be maintained like ur points and plug for proper performance.

I like the thick ass reeds for my blasters and thin stock stuff that comes with kits for my shredders.

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closer reed stops may also help in higher rpm situations, but will also have a limiting factor

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my stock reed gila revved close to 12k according to the rpm calculator.

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It isn't a big problem when the reeds start to flutter at high rpm (it's better when they close.that for sure).The thicker reeds do help but give's you some los at the bottom end. My Puch did 14.600 rpm with 0.35mm Polini carbon reeds.

One of the solutions is to use the V-Force. it's got 8 reeds so the reeds don't have to open that far and need les time to close.

Re: Reeds Limit RPM

Now that makes perfect sence , V-Force , huh . What is the best way to replace reeds that were not meant to be replaced. You know the ones that are riveted or cast with a rivet and then smashed for ever .

Drill and tap or drill and find tiny rivets to fit ,or solder?Any suggestions are welcome

Re: Reeds Limit RPM

I remember some dumb ass posting saying he took out his reed stops and gained some top end. Obviously thats a stupid idea, but would bending them back a little be acceptable? I just switched my express over to a carbon fiber deal, but I don't think I gained anything out of the deal. It was however, a little bigger, like a couple mm's than the stock one, maybe thats the prob.

Re: Reeds Limit RPM

Carbon reeds are closing faster than metal or plastic reeds.

So bending the reedstops can be usefull. Just try,they won't break that easy.

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I came across the topic of "rotary valves" in 2 stroke engines but have yet to see a motor using them. the cost of using them in production type scooter/ped engines is not an option but i'd like to see someone decide a conversion or a case that uses this form of induction for a high performance/ hi-reving ped/scooter engine. just my .02

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I've actually seen a puch e50 that was converted to rotary valve. It looks like it would be fairly complex to build, but it is interesting.

Heres an example, the top pic <https://www.mopedarmy.com/forums/discuss/read.php?f=7&i=100238&t=100146

Re: Reeds Limit RPM

Strange, the link didn't show up. https://www.mopedarmy.com/forums/discuss/read.php?f=7&i=100238&t=100146

Vespa and kinetic mopeds have a form of rotary valve stock, they use cutouts on the crankshaft which is a very simple way to go about it.

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A company called Sprocatti motori makes this kit for vespa:

Not to mention this:

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It's complex to build it on a e50 because the engine splits horizontal.

There is some info about that. I wil try to look it up.

Re: Reeds Limit RPM

drool

Re: Reeds Limit RPM

A ny ideal about my question from above about attaching new reeds to old cages?

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I bet you could drill out the old rivets, and tap the holes for small screws. Then maybe use red locktite on the screws.

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.35mm polini stock what "color" code is that with polini?? i understand they have like red, blue (stock), yellow, green, and white (thickest i think)

Re: Reeds Limit RPM

Polini 0.35 is the green one.

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all vespas are rotary valve, techincally, they just use the crank as the valve. kriedler had GP50 race bikes back in the day that were rotary valve. That sprocatti conversion is dope.

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i just measured the only set of polini reeds i have sitting around. they have blue screen printing on them and are .03 mm

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i also have red polini material, i guess, in sheets

that stuff is .55 and stiff as shit, thats what i'm running in my athena sachs rightnow.

Re: Reeds Limit RPM

on my athena reed valve 70cc ..

im well over the 10k mark.

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