Expansion pipe fabrication (49cc a115)

**dirtybomb** · 1st November 2007, 19:45

I'm after an aftermarket expansion pipe for my chinese pocket bike. So far I've put a bigger carb on, and polished the inside of the intake manifold.

Does anyone know if the efficiency of the current system can be improved on? If so, does anyone sell aftermarket pipes, or fabricate them to suit?

Any help would be awsome!

**Buddy L** · 1st November 2007, 22:41

To get one fabricate will cost you mega bucks, it cost me 150 bucks just to get a dent taken out.
cheapest, will be to find an aftermarket one.
If you have heavy pockets then give "Custom Chambers" a call might be able to help you.
For the right Dollars

**Sully60** · 2nd November 2007, 09:34

Originally Posted by Buddy L

To get one fabricate will cost you mega bucks, it cost me 150 bucks just to get a dent taken out.
cheapest, will be to find an aftermarket one.
If you have heavy pockets then give "Custom Chambers" a call might be able to help you.
For the right Dollars

Two stroke Performance tuning by Graham bell $60 odd bucks
Scientific Calculator
Brain in gear for the working out part.
$60 bucks for a 1.2 by 2.4m sheet of .8mm cold rolled steel sheet.
Mark the diffuser cones and baffles out on said sheet, cut out, roll up and weld together. I did this using some contacts from my trade and the whole shooting match probably cost me the priceof the steel sheet (already had the specs) for $200 you should piss in.

**dirtybomb** · 9th November 2007, 14:55

Thanks for the help fellas, but I managed to find an aftermarket one for a meazily $120. I'm expecting at least a small gain through the rev range, as the current mufflers fabrication looks pretty shocking.

Now I realy need a suibtable tacho for some sort of idea of gains. Where would I get one?

**BASS-TREBLE** · 9th November 2007, 20:30

Originally Posted by dirtybomb

Thanks for the help fellas, but I managed to find an aftermarket one for a meazily $120. I'm expecting at least a small gain through the rev range, as the current mufflers fabrication looks pretty shocking.

Now I realy need a suibtable tacho for some sort of idea of gains. Where would I get one?

Go to a bicycle shop and get a bike computer. But make sure that it is one where you enter the circumference, not the diameter because there really aint no bikes with like 6.5 inch tires. Circumference on my pocket bike was 95cm.

I can take pictures of my setup if you want.