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Post by pitobread on Jul 3, 2019 11:46:31 GMT -5
Got me all fired up.
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Post by supascoot on Jul 4, 2019 9:34:48 GMT -5
Those are beautiful pieces. How are you going to handle the intake? Rotary valve, it's the inlet near the flywheel |
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Post by jackrides on Jul 4, 2019 12:13:23 GMT -5
Spent a lot of time with A and F series Kaws (1970's). Thin metal ones were more reliable than the phenolic. Did you compare to reeds? History seems to say they perform better but do add volume to the crankcase.
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Post by supascoot on Jul 7, 2019 1:42:53 GMT -5
Has anybody got any useful pipe building information. It's for my 50cc daily. It has approx 194 degrees of exhaust duration and 133 degrees of transfer duration.(staggered) I have also modified the barrel to change transfer duct size, shape and discharge angles. I have tried a few different pipe calculators and all come out similar, engine will not perform. Tried different stinger sizes and header pipes. Most suggest 65-85mm belly dia. Engine will not perform unless belly is approx 100-110mm diameter. Made about 6 complete new pipes, getting frustrated.  I've had best results from some bodgy thing i made that just looked right with no measurements taken (went well), was just trying to improve that with some proven base starting point but that seems off. ??   |
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Post by pitobread on Jul 7, 2019 2:30:34 GMT -5
FOS pipe?
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Post by supascoot on Jul 7, 2019 2:47:34 GMT -5
Tried FOS calculations, on there atm. Performs terrible  |
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Post by 190mech on Jul 7, 2019 7:53:06 GMT -5
The link for JanBro's FOS calculator is in the first post of the pipe build thread; 49ccscoot.proboards.com/thread/10395/stroke-pipe-building-information?page=1It was originally posted on KiwiBiker ESE thread(page 1905),,What is nice about it is if the inputs are given correctly,the tuned length and % values are right on,from there you are on your own! Here are a few pipe specs that were posted on KiwiBiker a few years back;   Dont have a clue if either one will work for you,but it is worth some study,,both were race winning designs... |
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Post by supascoot on Jul 7, 2019 8:11:00 GMT -5
The link for JanBro's FOS calculator is in the first post of the pipe build thread; 49ccscoot.proboards.com/thread/10395/stroke-pipe-building-information?page=1It was originally posted on KiwiBiker ESE thread(page 1905),,What is nice about it is if the inputs are given correctly,the tuned length and % values are right on,from there you are on your own! Here are a few pipe specs that were posted on KiwiBiker a few years back; Dont have a clue if either one will work for you,but it is worth some study,,both were race winning designs... thanks. Both of those seem closer to what has been working than what I get when I enter data into calculators. Much larger header taper than what the calcs give me, which from experimentation works better. I have used that Jan bros spread sheet also. Must me entering something wrong. |
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Post by supascoot on Jul 7, 2019 8:13:23 GMT -5
The link for JanBro's FOS calculator is in the first post of the pipe build thread; 49ccscoot.proboards.com/thread/10395/stroke-pipe-building-information?page=1It was originally posted on KiwiBiker ESE thread(page 1905),,What is nice about it is if the inputs are given correctly,the tuned length and % values are right on,from there you are on your own! Here are a few pipe specs that were posted on KiwiBiker a few years back; Dont have a clue if either one will work for you,but it is worth some study,,both were race winning designs... The other link on the pipe building thread, my computer deletes it as it says it contains a trojan horse virus |
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Post by supascoot on Jul 8, 2019 8:53:27 GMT -5
Well don't I feel stupid.... The spreadsheet I was using for port timing calculations was way off. A friend of mine did it up for me a few months back and I never checked the formulas. I usually just use an online one. Never checked it with a degree wheel either as it's all experimentation. Some mate haha. Oh well I've probably cut up good pipes it's just none of it matches up to the right rpm ranges. Barrel is off again increasing port timings. On the bright side i was using the Jan bros spread sheet correctly 190mech |
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Post by supascoot on Jul 17, 2019 8:57:36 GMT -5
Could anyone advise whether or not a disc brake gear case will bolt on in place of a drum brake one??
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Post by jackrides on Jul 17, 2019 12:56:14 GMT -5
Your photos of what looks like welded on transfer ports amaze me. I'd Really like to know a lot more about that Please.
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Post by supascoot on Jul 17, 2019 17:46:34 GMT -5
Your photos of what looks like welded on transfer ports amaze me. I'd Really like to know a lot more about that Please. Unfortunately I dont I have anymore photos. I was looking for better duct shape and angles. I machined the sides off first. I then set it up in the mill and machined the radial and axial port angles to get an idea where things would end up. I used manganese bronze brazing rods and built up the inner sides of the transfers to get a nice shape, ground and smoothed till I was happy. The outer cover was done in several steps, I brazed a small bar across the bottom first and shaped it with the cases to get a gasket area, and then the rest of the outer was done in steps from the top down, shaping the duct as I went for ease of access. The cases were enlarged to the limit regarding gasket sealing. This was a damaged cylinder so I then bought a piston and took it out to 40.5mm and that took care of any distortion. The A tranfer shape was also changed at the exit to more of a trapezoidal shape towards the exhaust port. Any other questions just ask... oh and used key stock for the pieces of the cover. |
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Post by jackrides on Jul 17, 2019 18:53:10 GMT -5
Thanks! Think this would hold up for an exhaust port?
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Post by supascoot on Jul 17, 2019 18:58:38 GMT -5
Thanks! Think this would hold up for an exhaust port? Should do .. What were you thinking |
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I've had best results from some bodgy thing i made that just looked right with no measurements taken (went well), was just trying to improve that with some proven base starting point but that seems off. ??
