Why so few reed valves these days?

[PES+]

No comment

http://www.bergfeltracing.com/2cycleenginesandservice.html

 

[sawinredneck]

http://www.bergfeltracing.com/2cycleenginesandservice.html

Now, not trying to be mean, but the "no comment" thing, will get you harased more than posting normally!
Andy

 

[PES+]

I lost my flame suit

I just figured I'd let others blast this conversion rather than ask if the people that built it do not know that piston port is superior and they wasted alot of time and money building it. I have been a Yamaha owner since 1974 and can count on one hand their piston port engines.

*shruggs*

 

[sawinredneck]

I just figured I'd let others blast this conversion rather than ask if the people that built it do not know that piston port is superior and they wasted alot of time and money building it. I have been a Yamaha owner since 1974 and can count on one hand their piston port engines.

*shruggs*

RBW is the only one that came on hard, he just does that, don't take it personal, I went round and round with several members when I first singed on, still do on ocasion. But some of these people have done for me more than you could have imagined!!!! It's a decent site with a lot of good people, it's just "new" and easy to want to get involved with everything going on. I am a prime example. You just need to let people see you're true self and all will be fine in time!!
Andy

 

[Tzed250]

Torque Induction!

You are absolutely right PEST. Yamaha built its reputation on "torque induction". TI was simply a name for a reed valved, piston port engine. Notice the reference to piston port. A reed induction engine can be of the piston port style, or as is more popular today, a case reed induction setup. Yamaha built very few piston port engines, but the TZ250's of the early eighties were some prime examples of why a piston port 2-stroke is so strong. These engines dominated national level racing, but were extremely hard to ride. They made good power only between 10,500 abd 12,000 RPM. A modern case reed inductedTZ250 will pull cleanly from 9 grand on through 12,500 revs. The dominant engine in world level competition however, is a rotary valve style engine...a whole different ball of wax!

 

[PES+]

I knew that

The piston port reed setup is what I am in process with but I keep getting pulled back to the case reed induction because it can be more compact. I have considered rotaries but I owned and tuned a bunch of air cooled rotax RVs and they had loads of issues the main problems being lubrication and tolerence of dirt so as far as simplicity and reliability goes RV on a saw as far as I can see is impratical
Would make a fun open class project

 

[klickitatsacket]

pest, we need to talk. there is another system that works with the piston reeed port set up.

 

[Justsaws]

What was the first mass produced port saw?

 

[PES+]

Oye

Lombard if I remember right

I assume you meant piston port

 

[PES+]

I do not remember

I do not remember was it Solo?

 

[bwalker]

Of the differant two cycle engine types(reed, rotary, PP, etc) a piston port motor is always capable of making the most PEAK hp as there is less restriction than a reed or RV engine. Where a reed valve is nice is for application where you need transitional throttle IE hammering the throttle coming out of a corner. Reed valve engines produce more torque at lower rpms and have wider power spreads in general.

 

[Justsaws]

I do not remember was it Solo?

I do not know but I would like to.

 

[PES+]

And I had no intention of leaving the site

I do apologize for my part of the heat and yes I can act like a jackass sometimes and do apologize. I am new here and really like the site

I spoke with Dean and I am back to my search of old data and drawings that may turn out to be old school but there is this haunting feeling I have that reeds were thrown out too soon.

 

[RaisedByWolves]

PEST, sorry I was so harsh.


Glad your stickin around, its a good site and you seem knowledgable and like you could make some good contributions.



Again, sorry for being a :censored:

 

[PES+]

I appreciate it

We're good

 

[Chainsaw Master]

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".

Dolmar.....If I had to say the greatest improvement in recent evolution of saws has been overall reliability...Todays saws can go a year or two without any major repairs beyond maintaince.....not so... a few 5-10 years ago.

 

[manual]

pest, we need to talk. there is another system that works with the piston reeed port set up.

So talk here, sounds interesting.
Seems to me that you would have just P.M. Pest to begin with.
Lets hear it.

 

[ozflea]

Dolmar.....If I had to say the greatest improvement in recent evolution of saws has been overall reliability...Todays saws can go a year or two without any major repairs beyond maintaince.....not so... a few 5-10 years ago.

Most of this realiabilty has been the doing away with points and the introduction of electronic ignitions meaning one less wearing thing that needs constant re-ajusting of the timing.

Mc Bob

 

[klickitatsacket]

So talk here, sounds interesting.
Seems to me that you would have just P.M. Pest to begin with.
Lets hear it.

sorry man. I wasn't try to leed any one on. I was jsut in here and itwas easier to post in here then going to the PM.

It had to do with the Mac SP and CP 125 engines.

Here is a thought though for everyone to kick around. Why not put reed cages in the transfers? After BDC you are creating a vacume and drawing fuel back down the transfers until they close. I believe you could really gain an awful lot with a system like this.

 

[drmiller100]

Of the differant two cycle engine types(reed, rotary, PP, etc) a piston port motor is always capable of making the most PEAK hp as there is less restriction than a reed or RV engine. Where a reed valve is nice is for application where you need transitional throttle IE hammering the throttle coming out of a corner. Reed valve engines produce more torque at lower rpms and have wider power spreads in general.

what he said. piston port is famous for huge top end, and very little torque. in a chain saw, you can rev it up to max horsepower, then drop it into the wood.

do you REALLY care how much horsepower it makes at 7500 rpm?????

as far as putting the reeds in teh transfers, i think you are missign the theory of the piston pumping air from teh crank case into the combustion chamber. with that action, you don't need reeds in the transfers.