Goat, i can run 45+ all day on my 24" with the backwards motor. seriously. like i said before, i have no "official" proof, but i ride it in traffic in 45 zones just like a motorcycle. the videos i have show me on Newport Blvd, in the traffic lane, following cars.
since that video was taken, it's even faster. that was before my Supertrapp mod and now i'm running a 28T again.
when this bike's done and tuned up, my first priority is to get proof of it's speed. that's what i'm building it for, and i've gotta shut down any doubts.
thanks for the compliments, i appreciate it.
---
skjjoe, it'd be tough to make you a manifold without having the bike here to get all the angles right.
basically what i did was trace out and cut two flanges from 1/4" aluminum plate with a port-a-band saw. i made them both oversized so they'd be easier to work with. the flange to the engine is rectangular and has more "meat" on it, 'cause i hate the way the stock ones are so small around the bolt holes.
also, to make things a lot easier, i drilled the mounting holes and the hole for the pipe
before cutting them out. that way you have a nice big area to work with, and drilling is easier than cutting.
i found an aluminum pipe with an 1/8" wall thickness, and 1" O.D. at a metal supply place. it was a coupla feet long, so it's easier to bend. i just stuck it in the vice and heated it with a torch and bent it till i got the angle i needed.
then, doing some very careful eyeball-measuring, i cut it to the size i needed. the holes in the flanges, i drilled with a step-bit, and didn't drill the 1" step all the way through. to explain it better, the engine side of the flange hole is 7/8, and the other side is 1", so the pipe doesn't fit all the way through. same with the other side.
then i spent a lot more time eyeballing the angles again to get the carb level. since i already messed up the first one, i new what i was looking for. when i had all the pieces in place, i marked both the flange and the pipe in 4 places with a sharpee, then scratched them in with a scribe, since heating it up would destroy the pen marks.
the hardest part is the alumiweld. sometimes that stuff works awesome, and other times it doesn't work at all.
every surface it touches needs to be cleaned with a stainless steel brush, and a brush that has never touched anything but aluminum (or better yet, brand new.) any dirt will make it not stick. only brush one side at a time. apparently aluminum starts to corrode immediately, so if you do both ends, once you get to the other flange it'll be dirty already.
the pipe fit snug into the hole, so i put the flange on a brick (bricks are awesome for retaining heat) and stuck the pipe in where it goes, then heated it with a Bernzomatic Mapp gas torch until you can see the aluminum itself start to melt. then you scratch around it with the alumiweld stick till it flows. it's like soldering, but on a larger scale, and it doesn't flow as smooth. if it gets chunky, keep heating it or it won't stick.
after it looked like it was gonna work, i kept heating it some more just to show it who's boss.
then you let it air-cool. NEVER quench alumiweld. it won't stick if you do.
so 20 minutes or so later, when it was cool to the touch, i tried snapping the pieces apart, checked it (visually) for pinholes, then went on to the other flange.
cleaned it again, then repeated the process.
be
very careful when directing the heat. if the first flange gets too hot, it'll melt the alumiweld, and the whole thing's ruined. once you've messed up, alumiweld doesn't like to be ground off and tried again. usually you have to start over and remake everything.
still with me?
you got your manifold now, so stick it in the vice and grind the intake side to match the intake port. that's why i used 1/4" plate, so i had enough metal to get from a 7/8" ID hole to a semi-rectangular hole of the engine.
last step was to roll up a piece of rough sandpaper and run it through the intake a few times to rough it up.
blow it all out with carb cleaner or something, polish it up, and hope that it works.
the reason i say "hope," is 'cause alumiweld can be a real (bunch of asterisks) to work with. mine seems ok, and i really hope i'm not rolling down the street one day, hit a bump, and find my carb hanging from the throttle cable, with gas dumping on my shoe.
It is well known and proven enough that a properly clean up china will go a very long time! and run sweat.
