custom expansion chamber

[drizzle]

bought this from a member for the low price of $45. appears to have been made with a pocketbike exhaust and a red tube filled with what appears to be... like, wool or something.

lots to do still. but here's some pictures of how it looks so far-






with the panel-




after a hesistant run (didnt want it to break off at the head!), I was somewhat dissapointed. top speed of about 25. as opposed to my usual 35. i'm hoping that upjetting will improve it!

also, exhaust smoke comes out both ends of the red "silencer". hopefully some sort of exhaust wrap will help...

and most obvious, i'm going to make a bracket ASAP to bold it all to the case.



anyone have suggestions as to what size main jet to look for?

[bakaracer]

88 jet with airbox modded and 90 with no filter in the airbox.The j on the pipe and section that connects to the bell of the chamber should be shortened or use a larger pipe and step it down to the pipe theat is connected to the bore.Look at how the good aftermarket chamber pipes are and you will see what I'm talking about.If you fix that,the performance should get better and also the topend.

[Wheelman-111]

Greetings:

You might also consider pulling the wool out of the silencer to determine what effect that stuffing is producing.

It will likely be Loud, so perhaps some objective before-and-after testing (with a stopwatch) will minimize Noise-Induced Placebo Effect. Loud bikes always feel faster.

[drizzle]

running it without the "muffler" proved to be painfully loud. not that it wasn't already absurdly loud to begin with!

bakaracer, i see what you mean about shortening the first part. first though, i need to find somebody who can weld. the chamber seems like it would curve quite well around the case.

[mr pibbs]

As they say... loud pipes save lives.

[drizzle]

alright, so this is what i'm thinking in terms of changing it-




as compared to before...

[bakaracer]

If you can find a fatter pipe section,put that in between the camber and the pipe section where that heat shield is and add that fatter section from there.Find one that is the same diameter as the begining part of the chamber or just a little bigger.

[Dac]

you bought that from Skip (aka Timcat) didnt you?

i tried to explain all these things to him back in the day about how the longer the down tube the sooner the 'powerband' hits. I tried to explain to him that with a down tube that long its questionable if you will even hit a powerband, but he was high as * and had a hard time following anything i told him.

First things first your gonna want to shorten that down tube to as short as possible. Next you are going to want to take a wire brush (for like cleaning shotguns and what not) and use it on the down tube to get any built up carbon out of there. The most important thing on a two stroke exhaust is flow. If there is any thing slowing up flow, or any carbon that will disrupt flow it will throw off everything.
Also, when it comes to putting this bad boy back together you are going to want to two ends to butt up perfectly, then weld around that. Sure, if one end slides into the other end it may seem easier, but it will really mess up the echo effects that two stroke chambers need.

Make sure you wash the pipe out nice a good before you try to run it. I like to use a little carb cleaner followed by compressed air. MAKE SURE YOU CLEAN IT. If there is some metal shavings in there, the first time you fire up the bike those shavings could get sucked up into your cylinder ruining your top end in seconds.


As for the silencer (the very end part that is red). Im not sure what timcat might have stuffed in there, but it would be smart to take it out and repack it. You could run to a dirtbike store and buy some silencer packing for like $15 . or you could go in your attic, your garage, or your buddy's garage and steal some insulation out of the walls. Its free, and its works just as good (if not better). Find a long screw driver and pack it in there. you want to avoid getting any in the center tube, but you want to pack it all the way around it inside the red tube. (sorry im bad with explaining things).


Dont forget to clean it out before you use it, and you should be ready to rip.

[drizzle]

thanks a ton for the info. i found out a good friend of mine actually can weld, so he's going to do it for me. i'll post up results when i get some.