Help with pipe design

losthope · Post by **losthope** » Sun Mar 22, 2009 9:09 pm

I am going to try to build a pipe for my 2001 elite. The bore is stock and i need some help with some of the values on this program i have.

1.exhaust port effective diameter mm = 24mm

2. Diameter of Barrel flange mm = 226mm

3. Length from piston face to flange mm = 40mm

4. Exhaust port opening angle (deg ATDC) = 101 degrees ATDC

5. Engine speed at maximum power (RPM) = 10000 rpm

any help appreciated

losthope · Post by **losthope** » Mon Mar 23, 2009 5:11 pm

so what rpm does this motor make peak power?

bakaracer · Post by **bakaracer** » Mon Mar 23, 2009 7:28 pm

http://www.hondaspree.net/other/SA50_88-02_service.pdf

losthope · Post by **losthope** » Mon Mar 23, 2009 9:01 pm

ok so the only thing i could find in the manual was the exhaust port opening angle.

It says 79degrees before bottom dead center.

I need after top dead center so, Am i thinking correct to say the exhaust port opens 101 degrees atdc? thanks

Wheelman-111 · Post by **Wheelman-111** » Tue Mar 24, 2009 12:40 am

Greetings:

My legendarily bad math skills tell me you are correct.

losthope · Post by **losthope** » Tue Mar 24, 2009 5:15 pm

one down four to go!

So does anyone know what rpm peak power is made?

Wheelman-111 · Post by **Wheelman-111** » Tue Mar 24, 2009 5:37 pm

Greetings:

Not sure what the stock specs will tell you. Presumably the pipe you plan to build will increase the torque curve and/or move it to the right. For the sake of argument, let's say Honda-san's numbers are 4.5 hp@7650 RPM, which is I think pretty close to what I've read, depending on the model.

losthope · Post by **losthope** » Tue Mar 24, 2009 6:09 pm

ok so im going to say 7500rpm. id rather be a little low than out of reach.

losthope · Post by **losthope** » Tue Mar 24, 2009 6:11 pm

so what is... exhaust port effective diameter? im not sure what that means? maybe just exhaust port diameter? What do you guys think?

bakaracer · Post by **bakaracer** » Tue Mar 24, 2009 8:27 pm

yup!........ how high rpm are you planing on designing the pipe for?

losthope · Post by **losthope** » Tue Mar 24, 2009 10:08 pm

bakaracer wrote:yup!........ how high rpm are you planing on designing the pipe for?

im not sure. what do you think? 8000?

losthope · Post by **losthope** » Wed Mar 25, 2009 5:49 pm

so am i correct in saying the "Diameter of Barrel flange" is just the exhaust flange?

Dac · Post by **Dac** » Wed Mar 25, 2009 9:04 pm

sorry in advance for what end up a "rude" comment.

But, why are you making a pipe?
You have a dio, one of the most modifiable bikes in the world. There are pipes all over the place for this bike. Its not like your on a spree or a SE50 where pipes are rare/not around. Its a Dio.

Warning- here comes the rude part...
By the look of the topic it really dont seem like you know what your doing.
If you have cash to make a pipe, seems like you would have enough for a cheap dio pipe.
So whats the deal?

losthope · Post by **losthope** » Wed Mar 25, 2009 9:41 pm

Dac wrote:sorry in advance for what end up a "rude" comment.

But, why are you making a pipe?
You have a dio, one of the most modifiable bikes in the world. There are pipes all over the place for this bike. Its not like your on a spree or a SE50 where pipes are rare/not around. Its a Dio.

Warning- here comes the rude part...
By the look of the topic it really dont seem like you know what your doing.
If you have cash to make a pipe, seems like you would have enough for a cheap dio pipe.
So whats the deal?

Hey man no worries.

Well first off im pretty broke right now cause i just got finished building my entire house. I can build this pipe for a couple dollars. im very interested in how 2 stroke pipes work, and for me part of that interesting process is learning something new. some times the best way to learn something is to do it first hand. I like the challenge of building a 2 stroke pipe due to the many factors that effect the performance of the pipe.

AS far as not knowing what im doing you are somewhat right. I have never built a 2 stroke pipe before.
I have very little experience with these scooters and all the questions above are specific to this motor. I dont know what rpm this motor makes peak power do you?(and as far as i can tell no one else does either!)or they dont want to reply.

If these questions are so simple why has no one answered them?
Although with burnt toasts reply in my other post (thanks for the efforts) 2 more questions are answered.

I have built a few turbo cars and a few dirtbike/atv motors in my day so i have a pretty good understanding how to tune and how an engine works.

Peace

Kenny_McCormic · Post by **Kenny_McCormic** » Wed Mar 25, 2009 9:54 pm

Peak power is determined by the pipe! Most 2 strokes don't "wake up" till they get past 2000-5000 RPM.

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Help with pipe design

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