nme...190mech is right. You can do many things to a stocker but just swapping pipes simply makes noise and creates tuning problems. In my early days, on a '75 RD-350 I had changed pipes and made noise but could not make 100 mph with tuning. (It was slower top end) Frustrated, and with some brain power as he suggested above, (my mentors were Rick Schell, Bob Works and more) I went back to the stock pipes, but with better carb tuning and a TZ type port design, to match an older 350 race bike. Eventually made 110 mph.
The picture we are trying to paint is pipes are pipes. Tune to them as they are...max out what you have, then go to more performance, but do not start with the pipe, though many do. To me? It is like herding cats.
If you start with a performance pipe, you will need some coin to chase it. The fun never stops. IMO, if you KNOW what you want, you can find the answers, or close right on these pages.
My scooter example, is my Gyro. I wrote a note to 190mech, to ask for pipe help. He gave me some advise and a pipe target to shoot for in building. I build that "spec", but the first one was crap. The design was great, but could not make it fit my scooter as spec would have it, so had to deviate. The "design" setup was a +2 hp gain on paper. On an engine dyno was +1.3. That was until I tried to fit in in the scooter. Head pipe issues. Since then I have changed the geometry and direction of the pipe flow, but not "exactly" the given spec. Plus, I have learned to TIG weld much better.
It looks like shit, but makes 10,000+ rpm and now near 9 hp. Many mods, many money. Still only does 30+ mph, but Super power down low to mid range, and not bad top end. (Do not laugh, it is an OEM three wheeler with stupid wide rear tires)
Post by Mech Warrior on Jul 11, 2020 12:57:34 GMT -5
Well it is to My best understanding that the pressure waves do travel up and down the gas flow at the speed of sound. The "bang" is a set of pressure waves. With doppler effect, the downstream wave travels a bit faster than a return wave. I have seen this accounted for in some of the mathematical models which attempted to explain or predict head pipe and collector performance on 4 stroke aircraft.
Perhaps the return waves from the diffuser, midsection, lower unit, snout, etc. consist of a more or less random selection of waves that have few minor nodes here and there which variable with RPM. I would feel almost certain these are insignificant compared to the wave coming off the paired cylinder. I would bet they are untuned or diffuse which is why "tuners" have so little effect. All they are doing is moving the flow of air.
Everybody is a genius but if you judge a fish by its ability to climb a tree it will live its whole life believing that it is stupid.
Post by fernandomaloca on Nov 4, 2020 21:52:26 GMT -5
I have already made some in stainless steel. I want to make others in the right measures. I'm from Brazil. new to the group i have a jog cy 50 2001, I will send photos of what I have done. so who can give me a hand with an exhaust calculator or send me some models I am grateful!
Paul Yamaha Aerox NS50 2016 Piaggio Typhoon 2019: The new one Yamaha Slider 2002: The problem child (sold) Yamaha BWS NG: The Family affair (son now owns) Yamaha Aerox YQ50 2008: The fast one (sold) Yamaha Jog RR 2004: The first one (sold)
Senna1Rossi: Thanks renagade281!
May 23, 2016 14:59:12 GMT -5
Fox: I don't really know how to say this but straight. I am Dave's Girlfriend Kellilee and bluntly and VERY SADLY he passed away early Tuesday morning. I know he would want ya all to know this. Thank You Brent for befriending my love he was very happy on here!
Jun 18, 2016 16:26:04 GMT -5
Fox: www.gofundme.com/29mgf6b8 I hope it is ok to pass on his gofundme page link. If not you will un-post it I'm sure. Thanks again all!!
Jun 18, 2016 16:31:18 GMT -5