Reed Stoppers

[coffeeguy]

Is using reed stoppers a good idea for aftermarket(CCM) reeds on a 7000 rpm motor?

[wrechin2]

The reeds will only open so far. That is why mercury quit using them. Take a reed and blow compressed air into them. They will stand straight out and not bend over backwards. Just my experiences.

[ChrisCarsonMarine]

Some factory Reeds use stops, some don’t. You’re much more likely to break a read with a backfire if it doesn’t have a stop, Chris

[wrechin2]

IF you want some, I have plenty.

[FMP]

Turn them into dodgers or bling for big plugs

[ChrisCarsonMarine]

Generally speaking, I would ask what you have against reed stops? I tend to agree with James and that the reeds do not use the stops in normal operation, so it would seem they are unnecessary. However during a backfire the stops may keep a reed from breaking, Not a bad thing. Now, if you’re a fellow who likes to cut his crankcase front .050 to gain a 30 mL stuffing, realize that you will lose about 12 mL,By leaving the reed stops out, slightly over a third of the gain you got by the milling. Doesn’t sound good to me. As to the factory deleting them, they come on all the four and six petal cages, and do not come on the five,Stock or sport jet., Chris

[FMP]

I gained 60 rpm, just following instructions by manufacturer. I'll try yours and compare.

[H2OPERF]

I agree with chris, stack em all up together off the reeds on the bench and it looks like a big chunk of metal and makes you say hmmm... along with all the other metal you already hog out of a block trying to get it to flow nice.

[FMP]

We have an interesting thread going here call crankcase compression.

[H2OPERF]

Unfortunately omc's don't have much, I put big fr4 1/4in shaped/radiused blocks in my front and still put the stops in..

[phillnjack]

My question would be ... Why take the stops out ? what advantage would it be to run without them ? something ive not done in the past so would like to know.

" if " there is more chance of keeping the reeds intact during a back fire that is definitely a good enough reason to keep them.

what about a sneeze situation ? do the stops also help here ?

[coffeeguy]

Original reed blocks in the engine did not have them but I have some from an older motor.

[Chaz]

When I had my billet blocks made , my next stop was to the waterjet guy for some stainless reed stops . My reasoning was that if the reed is opening and closing at the anchor , the hinge point is very short compared to the pedal rolling around a radius .
I can't help but think that the reed will last longer as well as be much more stable with a little guidance . :D

[powerabout]

omc put shims under the reeds stops on several performance production engines

[H2OPERF]

Agree, was also told by a cart guy that bending at a even curve makes them recoil without flutter.. Sure is funny 2 stroke race bikes all came with them in.

[FMP]

How many hrs do you think you're going to get. Throw them out and get a fresh set, run without.
Boysen , run without check after a 100-200hrs during fall complete once over.
Interested to compare the two stage to the different stiffness from CC.

[Mark75H]

Had the devices in question been named "reed harmonic dampeners" almost no one would want to removed them

[Chaz]

How many hrs do you think you're going to get. Throw them out and get a fresh set, run without.

Buy a new pair of shoes . Do they wear out all at once , or over time ?
Drop 1000 one dollar bills out of an airplane 10' feet in the air . Then 100' then 1000' then 10,000'. Is there a point where they become easier to find ?

No , everything deteriorates with use / over time .... ;)

Since I stock anything that will fit in a 3.0L and reeds that fit my custom blocks , I don't need to go to far to "get a fresh set" . Going out of my way to stretch and tear the fabric .. I'll leave that up to the "Three F's brain trust" :nonod:


Run without .. ?
Since most come with , does that mean just take the plate off and use only the screw head to hold each leaf down ... :rolleyes:


Boysen , run without check after a 100-200hrs during fall complete once over.

Must be in code ..
(run without check) Gotta be a Canadian thing .. most do pay the bill , just never tip the waitress ... ehhh

(after a 100-200hrs during fall complete once over.)

Got do skint knee from fall .. ?

OK , seriously , you do a once a year complete systems check , yet give the reeds a pass without looking at them ... :nonod: :nonod: :nonod:



Interested to compare the two stage to the different stiffness from CC.

Will you use your flow bench , dyno or spintron .... :p

[powerabout]

Racers reed test

[FMP]

Haven't heard from you in a while, starting to miss your humours self righteous interpretation, your clown show following shouldn't be far behind to prop you up.
Big-time expert man that you are. How can us little minds compare to you superior understanding of all that is. If the m,m,m , manufacturer recommends no stops then you must be correct.

[Chaz]

We Racers reef test

Well pow-pow , I recon I have to admit I'm not up on all the latest scientific testing methods .. :nonod:

So you'll have to explain how "running aground" will determine the condition of a reed .. :eek: :)

BTW ... Is there an "F" anywhere in your first , last or middle name ???


https://www.youtube.com/watch?v=145kvqPcows

[FMP]

https://www.youtube.com/watch?v=Mb45tJhzmcI
the great CHAZ

[Chaz]

Well if that's your deflective answer to :

Why Canooks don't tip waitresses .........

What you do to locate the reeds when you throw away the stops .....

If you don't check the reeds after 200 hours of use , then when ....

How your knee's are healing after the fall .....

What procedure you will be using to test . Flow bench , Dyno or Spintron ....

Then Scarecrow .... here is your diploma :p


https://www.youtube.com/watch?v=ky7DMCHQJZY

[phillnjack]

stop with the silly stuff guys and get back to the reed stops, be a shame for another good post to go wonky..


My take on this is that If the stop were not needed then I am pretty sure omc would not of fitted them to all their motors for so many years.
Imagine how much money and time could of been saved by not having to make and fit these lumps of metal.

Now I dont know about using the stops with fibre reeds , but with steel reeds they obviously done the trick.
I dont think steel reeds would of lasted as long as they have without the stops fitted at the factory....
Some motors have lasted 20 years or more and had tons of abuse with their metal reeds and the stops still in the motors from the day they were made..

From what I have read on numerous sites and spoken to people with fiberglass, carbon and fibre reeds, they dont seem to last the test of time like the
OEM steel reeds with the stops in place as from factory etc..
BUT 90% of these I have spoken to have been with aftermarket performance reeds have been running WITHOUT the OEM reed stops .

Would or could the after market reeds last a lot longer with the stops on say a average fishing motor ?
and would or could the same be said of running the same after market reeds on a high performance motor IF the reed stops were fitted ?

for Chris Carson
When using your reeds you say to use the stops, would you also say to use the thin metal shims as well between reeds and stops on omc reeds ?
.
.
.

[FMP]

Just enjoyed a good call with CCM, going to try the thick spacers and a set of reeds. I just can't say I'm going to use the stops.

[ChrisCarsonMarine]

I am know the little shims are used on some of the crossflow cages,on the long side,I don't know why...have asked several long time omc factory guys,Either no one knows what they are all about or it's a well kept secret.Fill me in if you can,Chris

[Chaz]

stop with the silly stuff guys and get back to the reed stops, be a shame for another good post to go wonky..

Hey phillin ... I'd never say Benny Hill was wonky ... ;)
So let me ask , would you rather let a thread go on with , hear-say , wifes tales , total non-sense statements , so far from the truth ,
out in left field ideals that only fit their agenda ... or would you rather see someone call them out and hold them accountable for what they say .... ??????
Now I enjoy a good fiction novel as well as the next guy , but I know what it is when I pick it up . This is a tech section , and you have seen over and over what happens when their lunacy is put to the test ... all they have is deflective or non existent response's .... :D



My take on this is that If the stop were not needed then I am pretty sure omc would not of fitted them to all their motors for so many years.
Imagine how much money and time could of been saved by not having to make and fit these lumps of metal.

Now I dont know about using the stops with fibre reeds , but with steel reeds they obviously done the trick.
I dont think steel reeds would of lasted as long as they have without the stops fitted at the factory....
Some motors have lasted 20 years or more and had tons of abuse with their metal reeds and the stops still in the motors from the day they were made..

From what I have read on numerous sites and spoken to people with fiberglass, carbon and fibre reeds, they dont seem to last the test of time like the
OEM steel reeds with the stops in place as from factory etc..
BUT 90% of these I have spoken to have been with aftermarket performance reeds have been running WITHOUT the OEM reed stops .

Would or could the after market reeds last a lot longer with the stops on say a average fishing motor ?
and would or could the same be said of running the same after market reeds on a high performance motor IF the reed stops were fitted ?

for Chris Carson
When using your reeds you say to use the stops, would you also say to use the thin metal shims as well between reeds and stops on omc reeds ?
.
.
.

Honest question's and statements deserve the same respectful responses ...
You have pretty much hit the nail on the head . The steel reed goes back to a paper clip . Don't take long to break it when it is bent to an extreme angle over a short span . Yet limited to working just far enough to hold a small stack of papers together .. well It will provide a long service life .. :thumbsup:
Fiber .. or is that fibre .. ;) Mercury Racing took the "Harmonic Damper" :) off of the carbon reeds and just put a small flat strip across the reed behind the hinge point . Street mentality becomes , if it works for carbon reeds on short run racing units , it's gotta be even better on everything from weed whackers to lake outboards , no matter how much common sense logic is piled up against it ... :rolleyes:

Anytime a part such as a stationary radius plate is shimmed away from a moving part it's meant to control .. they are providing a little wiggle room for tolerance stacking . The reed gets a little autonomy and the parts as a whole don't need to be held to such a tight tolerance .



FMP

Just enjoyed a good call with CCM, going to try the thick spacers and a set of reeds. I just can't say I'm going to use the stops.


I see that diploma I gave you is starting to work a little .... :D

[W2F a V-King]

The Mercury 2.0 2.4 V6 motors That I have built came without these. Are there aftermarket stops available?

[phillnjack]

Chris Carson's Marine;3015165]I am know the little shims are used on some of the crossflow cages,on the long side,I don't know why...have asked several long time omc factory guys,Either no one knows what they are all about or it's a well kept secret.Fill me in if you can,Chris[/I]


I Have an idea about the omc shims between reeds & the stops ( I could be totally off on this , but its my thought only ).

With the reeds being stainless & the stops being just a mild steel there could be a corrosion or reaction problem if the two metals
were in constant contact all the time. ?
in an ideal world there will always be a slight film of oil on the reeds and stoppers & shims all the time, but sometimes they can be very dry.
reeds I just took out today are bone dry ?
dry steel in contact with dry stainless in a damp environment = RUST leading to reeds possibly sticking to the stoppers ?????.
so maybe the tiny little thin stainless shim helps with this, Plus maybe give the reeds a bit more chance to curve when open ?

(I did say its just my thought on the shims, I am ready for this to be shot down, as most of my common sense idea's are normally wrong :mad: )

If fitting composite /fibre/glass reeds maybe the shims could or should be taken out ? no idea on that. this would be more down to the
designers of the reeds to find out what is best for their particular product, this involves R&D (testing) .....



p.s
my opinion on testing any product is.
All R&D results good/bad should only be told & or shown to those supplying the product for the testing.. that is what R&D is all about
anything other than this can be considered industrial espionage :eek:)
.

[ChrisCarsonMarine]

I Have an idea about the omc shims between reeds & the stops ( I could be totally off on this , but its my thought only ).

With the reeds being stainless & the stops being just a mild steel there could be a corrosion or reaction problem if the two metals
were in constant contact all the time. ?
in an ideal world there will always be a slight film of oil on the reeds and stoppers & shims all the time, but sometimes they can be very dry.
reeds I just took out today are bone dry ?
dry steel in contact with dry stainless in a damp environment = RUST leading to reeds possibly sticking to the stoppers ?????.
so maybe the tiny little thin stainless shim helps with this, Plus maybe give the reeds a bit more chance to curve when open ?

(I did say its just my thought on the shims, I am ready for this to be shot down, as most of my common sense idea's are normally wrong :mad: )

If fitting composite /fibre/glass reeds maybe the shims could or should be taken out ? no idea on that. this would be more down to the
designers of the reeds to find out what is best for their particular product, this involves R&D (testing) .....



p.s
my opinion on testing any product is.
All R&D results good/bad should only be told & or shown to those supplying the product for the testing.. that is what R&D is all about
anything other than this can be considered industrial espionage :eek:)
.Amen to that!
For what it's worth remember the shims are only on the long side of the cage...Chris

[phillnjack]

on mine they are on both sides, I only have a omc 56 .. both sides are the same on this.

[ChrisCarsonMarine]

on mine they are on both sides, I only have a omc 56 .. both sides are the same on this.
Interesting,Iv'e done mostly v4 and v6's,some have one on the long side,some don't...never seen one with one on both sides,Chris

[Steve Pope]

I was on the understanding that the " reed stopper" was not intended to limit reed opening but acts as a damper.???

[Dave S]

In the old ...dazzz,,,kg9 mk 20 had the crank spinning past the reeds. Need a stop. Or crank got in a game of hittman ... Later L6 had stops but 2 different styles. one had a break point the other had a smoth tranisiliton. Sorry for sp/, old motors need stops......

[phillnjack]

This is what mine look like
1 complete reed cage and one set apart ..
showing 2 reed leafs and 2 shims and 2 stops and 1 empty cage.

these are what the omc 3 cylinder 56 reeds are like on 1995 oval port, from part no its the same on all the 56 motors
reeds are same length and so are the stops.


.397615

[FMP]

The good five panel Chryslers from the 70s are the same style with the curve stop and shim strip. When using aftermarket reeds the stop not used , the strip is. No issues at all doing this except a gain in rpm, for this application. About 2.8+ square inches for the later Force five panel.

[Dave S]

Shimm used a breck point.

[phillnjack]

" Shimm used a breck point "

what is that supposed to mean ?

[DanUmbarger]

Just got done putting my new CCM reeds in my Johnson 1975 135...it had no shims but did have stoppers which I reused while installing the new reeds. Is there a rhyme or reason on when the shims were used and when they were not? The only reason I changed the reeds is that I don't want to destroy a 42 year old engine by sucking a steel reed. Also my old reeds didn't have any of that weird staining shown in an earlier post.

[phillnjack]

are your 135 stoppers the ones with the 3 slots or the complete plates ?

[DanUmbarger]

My stoppers have the slots cut in them...although I have seen the solid plates before.

[phillnjack]

slotted stops are the original ones fitted to the 135.
with the original metal stops the reeds could no way get bent enough to cause metal fatigue.

newer reed material lets the reeds move more easily, but it would seem that modern materials dont last as long.
Or are these newer reeds only lasting a short time due to the motors being modified for a much higher rpm ?

if the rpm was kept down to say 6,000 to 6,500 rpm as per fishing motor, how long would newer type reeds last ?

[Mark75H]

slotted stops are the original ones fitted to the 135.
with the original metal stops the reeds could no way get bent enough to cause metal fatigue.

newer reed material lets the reeds move more easily, but it would seem that modern materials dont last as long.
Or are these newer reeds only lasting a short time due to the motors being modified for a much higher rpm ?

if the rpm was kept down to say 6,000 to 6,500 rpm as per fishing motor, how long would newer type reeds last ?

Depends on the thickness and the epoxy base. Reeds with approximately the same tension as old steel reeds will last as long as steel reeds at fishing RPM. Go thinner, lighter tension and life reduces regardless of RPM.

[H2OPERF]

Just an opinion but i really don't like the solid plate stops for several reasons, A. they have to produce some kind of dampening effect as the volume on the back side between the reed and solid plate has no where to vent except the ends.. B. They have allot of oil/gas weted surface for them to stick to which you would think could slow the recoil on closing.. C. the intake charge drawn into the case between the petals is restricted.. Just my own theory but why i have never liked them..

[DanUmbarger]

I emailed Chris about what reeds to use and he recommended the 144R reeds. It appears they sell 3 different types...S, R and D...standard,race and drag. Now I'm curios how long these reeds will last and should I have gone with the "s" type. This is not going to be a race boat but I'm going to try to run this motor at the upper RPM limits...prolly 5800 - 6200 RPM.

[ChrisCarsonMarine]

I emailed Chris about what reeds to use and he recommended the 144R reeds. It appears they sell 3 different types...S, R and D...standard,race and drag. Now I'm curios how long these reeds will last and should I have gone with the "s" type. This is not going to be a race boat but I'm going to try to run this motor at the upper RPM limits...prolly 5800 - 6200 RPM.
They will last a long time...they're are a little stiffer than the sport version,Chris

[FMP]

The 265xr , is that a small five panel? Sport version?

[ChrisCarsonMarine]

Large 5 petal used in hipo 3.0 mercs,Chris
The 265xr , is that a small five panel? Sport version?

[FMP]

Slightly disgruntled

[DanUmbarger]

Thanks for clearing that up for me Chris :)



They will last a long time...they're are a little stiffer than the sport version,Chris

[phillnjack]

They will last a long time...they're are a little stiffer than the sport version,Chris


what do you call a long time ? a long time to some is a short while to others.
a teenager thinks 2 weeks is an eternity

[coffeeguy]

My first set of CCM reeds are still going. s series to 6800 and I can't remember how long ago I bought them

[phillnjack]

well atleast give us a rough idea, 1 year , 2 years, 3 etc.. no point saying a long time and then I cant remember.

I have heard of reeds lasting less than 50 hours, some less than 20 hours, and some that broke straight away after a bad sneeze on start up.

[gfinch]

I would ask probable HOURS not years.
well atleast give us a rough idea, 1 year , 2 years, 3 etc.. no point saying a long time and then I cant remember.

I have heard of reeds lasting less than 50 hours, some less than 20 hours, and some that broke straight away after a bad sneeze on start up.

[Chaz]

well atleast give us a rough idea, 1 year , 2 years, 3 etc.. no point saying a long time and then I cant remember.

I have heard of reeds lasting less than 50 hours, some less than 20 hours, and some that broke straight away after a bad sneeze on start up.

Phil ,
In all sincerity , there are those who can make a toothpick last a year while there are those who can break an anvil with a rubber mallet within hours . There is no telling what type of skill set you possess have or have not .

If your the type that needs to be protected from yourself , then as my homeboy the used car manager says , Sir I'm sorry , the new car lot is on the other side of the dealership ... > :thumbsup:

[Chaz]

Phil ,
Mr. Carson is without doubt on of the most fair and honest hard working people I can think of .
I bought one of those sets of yellow reeds from him back when I had black hair ... :o

They went maybe 100 hour's because the rubber on my blocks were bedded in and dry . I think that might be one of the ones with a brown spot on the upper left corner . Can't hardly fault the part , for piss poor installation .. :nonod:

Merc carb's have 3 little holes under the throttle blades . Back when I was filling them shut and hand drilling them to what I wanted .. so I could blast off idle clean , I managed to rip one yellow leaf off of a prepped block , but never once since he went to the white reeds .
Or maybe he still sell's the yellow reeds , but to only those who are mature enough to have em ... ;) :D

Every used white reed in that box has aprox 250 hours on them . The ones on the blocks with the shorty stops came off of other peoples motors , I turned em over and ran them on my junk for another hundred hours . At the time , they were just starting to chip on the leading edge of the storm ..
So , 250 to 350 hour's in the hands of your typical boat guy ... less if you a total ( how you say ) wanker ..... :thumbsup:



https://i.imgur.com/K3waEqLl.jpg

[powerabout]

wankers is for aussies....
brits use tosser

[tux974]

Been dealing with Chris for years, have installed countless sets even in race applications and maybe 1 set had a tip crack.
As for longevity.....proper installation is also a key factor.
I can personally tell you from experience, he is very fair and honest.
He has also improved them through the years.

All brand break or fail like a motor does from time to time.

[olboatman]

Scribed

[Chaz]

wankers is for aussies....
brits use tosser

See brother ... I was lookin out fer ya .. :smiletest:

[phillnjack]

Just to clear things up.
We English use the words both Tosser and Wanker, we use the words as in "he is a tosser, or proper tosspot" if he excels in being a proper tosser then he gets to
be a Wanker.
This word wanker should be recognised world wide as the it would seem the entire world is becoming full of wankers.
Australians have used the word wanker a lot due to having more wankers than mere tosspots.


I am not nocking Chris Carsons reeds, I was asking in general how long the new carbon fibre (or whatever is used) reeds last on average.
(from what I have read on several different boat forums I would say the CCMS are rated at the no1 spot along with TDR, then boyesen coming in behind)..
If reeds break when fitting them , then obviously they are being fitted by a "master wanker" who should not be allowed near sharp objects or tool boxes.
How anyone can bugger up a simple job of fitting reeds is a bit beyond my mentality, I cant see how they could be fitted wrong, but there are those around who
can surprise us with their talents to do such things.

If a set of new high tec reeds will last say 250 hours plus in normal everyday use then I think thats not too bad, I dont do racing in my little boat, just messing about in general.

When out and out racing then obviously lifespans are out the window as you never know what is going to happen or break.

[Chaz]

To use proper English ... They are the dogs bollocks .

Cockney .. Feckking smashing bit O a kit mate .


Krakka ... Ya'all come on vacation , leave on probation ... ;)

[phillnjack]

To use proper English ... They are the dogs bollocks .

Cockney .. Feckking smashing bit O a kit mate .


Krakka ... Ya'all come on vacation , leave on probation ... ;)



since when would a cockney use Irish slang ? fecking is Irish, nothing at all to do with English..

[Chaz]

So this Sheila .. err .. I mean , a friend of my wife named Sheila is a limey . Well , when we all go out she puts lime in her tea . My wife says she's Cockney , she kind of looks like the girl in the Norton commercial in Cycle magazine in the mid 70's ;) and I just nod yup.. ahh ... ok .. yup ... cuz while she might be purrty - she don't speak a lick a English ... :p

Now , bout them reeds bein ... the Dogs Bollocks :thumbsup:

[ChrisCarsonMarine]

I’m familiar with that girl,and I still have the Norton...
As to the reeds life,how long do tires last...,but seriously,I have commercial guys with several hundred hours in midrange speeds,still looked perfect When we recently rebuilt a pair,changed em anyway.I would expect at least a couple hundred hours on a sport boat.
A river tour guy in Fairbanks Ak has a fleet of jet boats with 200 Optis that run continuously in season,3 seasons without a failure,5600 all day long.
to me thats a long time,thanks guys for the comments,Chris

[Chaz]

Tire life ... hummm ... seems totally dependent on who's paying for them .. :D

I do recall having one set of white reeds that had suffered a bit of premature chipping . It only affected one particular hole . The reeds in the other five cylinders were pristine . Never did figure out why they chipped ... :eek: :D


For that one person that doesn't know .... the above is a joke ... well not the tire part :nonod: :smiletest:

https://i.imgur.com/0ygAvMnl.jpg

[Dave S]

Not been here lately. What I meant as break line is on some reed stops a defined point at which the read starts bending. Early 99 cid mercs had reeds with that style stop. Later Hp motora had no break line but banjo reeds bent from an undefined starp point. Don't use the wrong stops on the right reeds......or the right stops on the wrong reeds....later 115 adi have a mix of reeds and stops to trick the motors air flow. I made a set of reeds for a L6 motor back in 1975 using phenloick sheets and they were stiffer than the steel reeds. I hand filed them......times are different.

[kielbasa]

Amen to that!
For what it's worth remember the shims are only on the long side of the cage...Chris
I think I have a pretty good idea for the reasoning of the shims....I stumbled upon this by accident while installing my CCMS reeds.
While looking and studying the assembled reed cages, I was wishing OMC would have used shorter fasteners that didn't protrude soooo far into the airpath. But wait, one side barely protrudes while the opposite side (short turn) does. Doesn't matter so much on the short turn side of the intake tract, as much as the long turn (which is where the shims are placed).
I took it one step further and installed 5mm lockwashers under the reed fasteners and now they sit flush with the reed cage, no more protrusion. I seriously doubt it will make any measurable improvement in power, but it was fun and easy, so why not.....

[Bruce2]

Tire life ... hummm ... seems totally dependent on who's paying for them .. :D

I do recall having one set of white reeds that had suffered a bit of premature chipping . It only affected one particular hole . The reeds in the other five cylinders were pristine . Never did figure out why they chipped ... :eek: :D


For that one person that doesn't know .... the above is a joke ... well not the tire part :nonod: :smiletest:

https://i.imgur.com/0ygAvMnl.jpg

So that is what a block stuffer is, don't think i need them stuffers now.

[71V153]

So that is what a block stuffer is, don't think i need them stuffers now.Well, least not anymore ...

[Motv18]

Stops for me are an examination of the functionality of the reed.

From pure discriptio. When plenum pressure is higher than crankcase pressure the reed opens and air flows in to the crankcase filling the area on one side of the crankshaft and connecting rod. The other side is already full ready to charge the cylinder when the bore opens.

As the crank rotates now presssure will climb higher than plenum air pressure in the crank case, close the reed and prep to stuff the cylinder.

Essentually the reed reed is an intake valve (for those who need the analogy)

reed timing is in responce time stops and such control that. Reeds that stand open to long don’t stuff the crankcase since it’s a positive pressure environment but allow back flow and reduce total volume to the cylinder.

Stronger lighter materals increase responce time to time to positive pressure letting less air out of the crankcase and open sooner to negative pressure.

While larger generally lets more in with reeds ehh someone who test would have to answer

thats basic theiry of operation ration and clues to fundamentals of diagnosis.