Finally complete my 2-stroke exhaust for my old abandoned motorcycle MX restoration Project Currently I'm quitting my everyday job to do RU-vid full time. Help me to achieve my dream, join my Patreon link: / crazyyuri
i made a lot of pipes with "2 stroke wizard". i liked the old V3 pipes... they had nice fat bellies :) no real benefit, iunno... they worked? but admittedly 5 did go better. though i never did any definitive tests on the "dual power", though i did make one that way... sometimes i feel like experimenting again... got a nice selection of perforated mesh now... my main trick on pipe layouts was to fudge the numbers a bit so all the cones and diameters worked into nice even integers, ie, a 24mm increase over 240mm was easy to make 12 20mm long sections with a 2mm increase each. rather than "243.7mm" at "24.6" increase... 7,892 RPM is close enough to 8000rpm, etc. play around with the RPM a bit, port timings all remaining a constant, of course. but i was also cutting them by hand on a bandsaw... and then, having a suitable length and number of pieces required, get a bit of welding rod, mark off each join, then bend it up to get the required angles. as i progressed i also made discs of the required diameters here and there for those tricky "tight squeezes". rough one up in stiff, 180GSM type paper... make sure it fits before actually cutting metal!
Check your squish band clearance i measured mine with some soft solder . Since your using reed valves the inlet side of the piston can be cut back . Definitly need to increase main jet , better still replace carb for japanese one , the MZ one wasnt vey efficent
Gearing is too tall, one tooth more on the countershaft sprocket. Wider bars. And definitely the Japanese carburetor with uni sock style air filter. Trim the piston like you said.
what is material, is that metal sheet cones or aluminum? and what kind of welding is that, looks like stick but no sputter and very clean? and third, what formula did u use to make the expansion chamber, what software or opensource table?
it's really stupid to do weeley when you don't have the sense for it.. 1 mistake never remove your foot from the brake. it would have saved you .. 2 never hold on to the bike if that happens .. you can get your finger and arms in the chain .. drop it and save yourself first..just the way you stood on the bike showed me what would happen.
So the engine threads stripped nothing rn figure ill see this it runs better without an exhaust lol. But the ports shoyod be the same who puts a smalll round pipe on a square exhaust outlit.
@@baby-sharkgto4902the port. The top is flat. The bottom usually is too. My little 121cc Suzuki 2 stroke toro mower motor I'm using on a minibike is essentially a rectangle with a curved side. I'm looking at all kinds of pipe videos looking for some ideas.
@@jasonbirch1182 i don’t even remember watching this video lol but I am aware of all shapes of ports, however there were no ports shown in this video. Furthermore regardless of the shape of the ports 99% of all expansion chambers are round. I never heard of a 121 two cycle Suzuki motor on a lawn mower but I just looked it up.. neat little engine though! Thanks for the comment.
@@jasonbirch1182yeah, i always got a bit anal over port matching... make mandrels. lump of steel, some grinding, bit of guess work... all of two stroke tuning is a bit of a guess :) so far, noones shown a decent video of whats going on inside a cylinder when running, its all just imagination and experience... but yeah... any abrupt change in section ruins the whole effect a pipe produces. it isnt just gas flow, its pressure waves and their reflections... whats annoying is some engines have a much larger flange than the port in the cylinder wall... like a stihl, needs a packer, a wedge to fill in half the flange to keep the dimensions all matched up.
@@paradiselost9946 right. A gradual change with shaps that promote gas flow is all you can do to go from oval/rectangle to round. I don't think that absolute flow in the port is that critical in the 2 stroke exhaust. The reflection is destroying that anyway plus a tiny stinger that is restricting more that the port.