Why so few reed valves these days?

The few reed induction saws are slowly being phased out and it makes no sense to me as piston porting is the least efficient form of two stroke induction.

I suspect the growing trend of cheap parts thrown together and money spent on advertising hype and fanfare even echo has gone piston port on their new AHEM "Pro" top handle

Better question, why arent more people modifying them?

I do

I do reeds take very well to mods and are capable of far more power than piston port. It seems like chainsaw engineering prowess is going BACKWARDS

Anyone who has ever run a properly set up stock hi horse Mac knows that for the displacement they had FAR more power than todays saws

When I was a kid the old Mac 101s were light, dependable, and kicked ass!
I had a racing go-cart that was about my fondest memory. It'd go over a hundred, and turn on a dime. What fun.
It had this cool manifold that split into two carbs, velocity stacks, and I didn't have a clue about how it all worked, but I beat the crap out of that thing day after day.

Yah

Did you ever blow the crank seals out of it? my ported and slipper piped 101As used to spit seals at the worst possible times

Newer 2-cycle engines rev higher than the older reed models. Another reason for the newer engines is fewer moving parts and lighter weight. I'm sure that they can make a reliable reed-valve saw that has more than 4HP and weighs less than 11 pounds but at what cost? Custom built race saws don't come cheap.

It is a very difficult to engineer a peice of equipment with the fewest moving parts, highest performance, lightest weight, longest durability for a reasonable marketable price.

If memory serves

My last two mac 101s were 19 horse with a megaphone and 23 or so with the pipe @ 14,000 RPM and were then stone realiable after I made my own seal stops and stopped slamming the slipper cable too fast

Not so

Reeds are not at all complicated nor are they heavy. Looked in one of the new strato charged saws lately? the other good point about reeds is fuel effeciency. And chainsaw mufflers are a bad joke.....they had better designs for scavenging and complete fuel burn 20 years ago

I guess there is no good reason for not using reed valves. Maybe the saw manufacturers just decided they didn't want to make good saws anymore.

Point of fact

Reed and rotary valve 2 strokes can rev MUCH further than piston port

PEST said:

Reeds are not at all complicated nor are they heavy. Looked in one of the new strato charged saws lately? the other good point about reeds is fuel effeciency. And chainsaw mufflers are a bad joke.....they had better designs for scavenging and complete fuel burn 20 years ago

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Perhaps, but those were in the pre-EPA days. Those days are gone.

PEST said:

Anyone who has ever run a properly set up stock hi horse Mac knows that for the displacement they had FAR more power than todays saws

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Sure, at lower RPM.. and dirty...

Stihl's stratocharged chainsaws don't use reeds... Only on the TS800 cut-off saws which by design are low reving.

I see....so the 2-stroke racing motorcycles are slow and lack power 500 ccs 180 horsepower @ 22,000 rev limit

I have now been enlightened

I agree with Lakeside here. 90% of the evolution of saws in the last 10-15 years has been purely EPA.

Not much has really changed in saws, they are just leaner and spit out less smoke. Side adjust oilers are newer, better AV technology ok, sometimes lighter and usually quieter.

All the rest of the differences and advances are pretty much geared towards making the saws more "green".

So closing your intake to compress the fuel charge makes a 2 stroke run dirtier?

hmmmmmm don't think so

I just wonder when there will be an inspection for saw emissions.
Porting and opening a muffler shoots all complience out the window.

Ever think about changing your name form pest to jackass?




If you dont agree with ppl say refute it somehow other than being a smart alec. This is a good discussion and I would really like some info on reed engines as they pertain to chainsaws.



Most everything you can find pertains to bikes and as I understand it not much of it works for our saws.



I can understand how a piston port could run higher rpm's than a given reed motor and how a reed motor with stiffer petals could achieve the same HP/RPM's but at a loss of low end torque.



What I would like to find out is fi there is anyone out there that has good "Woods" numbers for a reed engine saw jiven the stock reed stiffness.:help:

Reduction in parts manufacturing, assembly and wear. Reduction in purchasing and storage. Reduction in costs and increased profits with no consumer back lash. Ported was win win. Perceived saw reliability due to new design.

RaisedByWolves said:

Ever think about changing your name form pest to jackass?

If you dont agree with ppl say refute it somehow other than being a smart alec. This is a good discussion and I would really like some info on reed engines as they pertain to chainsaws.

Most everything you can find pertains to bikes and as I understand it not much of it works for our saws.

I can understand how a piston port could run higher rpm's than a given reed motor and how a reed motor with stiffer petals could achieve the same HP/RPM's but at a loss of low end torque.


What I would like to find out is fi there is anyone out there that has good "Woods" numbers for a reed engine saw jiven the stock reed stiffness.:help:

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I was thinking sap, but pest is way to smart for that, but...

PEST said:

I just wonder when there will be an inspection for saw emissions.
Porting and opening a muffler shoots all compliance out the window.

Click to expand...

Nothing new here - and well discussed on AS for years... it is illegal to modify a compliant saw to non-compliant. Get caught in CA (California) with a modded muffler, and it's expensive... Less chance of being caught elsewhere, but.....

Saws are all emission checked and guaranteed by the factory for a period of time (50-100-300 hours) depending on size, just like all similar devices. What likely to come is that repair station (DEALERS etc) will be required to retest saws when repairing them.. I've heard rumors of this already..

And.... Pest... If you are trying to lead a thread and add value, do so... Just playing the negative gets tiresome really quickly.