Once you have ported the exhaust you will get about a 30% increase, as the expansion chamber will work even better! Its an essential mod for anyone with an expansion chamber. You have mounted yours the same as mine, do you have any leg clearance troubles? I do a little bit if I wear shorts, but the clearance isnt uncomfortable though.
i have only put it on last night my thigh rests against it but only gets warm although i have only taken it for probly 2km ride but it is cool here at the moment to i was thinking of wrapping it in fibreglass tape the kind they use on extractors for cars as a heat shield i have allready shaved the head and opened the exhaust and inlet ports so i canstick my little finger in i have also cut a small piece of the piston skirt off i found when at top dead centre the piston skirt was protuding into the inlet port so i cut it off i also use a different plug and copper lead my son took it for a spin tonight and got 65kmph out of it without wot but it is very loud sounds like a dirt bike
Not really for a 2 stroke. For a 4 stroke maybe, but 2 strokes get their oomph from the expansion chamber.
Wheelsy, if you put exhaust wrap on your expansion chamber it moves the powerband a little higher in the rev range. This is due to keeping the heat in the chamber and not allowing it to escape.
Mate, just do the whole thing, I picked up a couple of expansion chambers today. Last time I bought a roll of exhaust wrap there was enough for 2 sets of pipes with some spare.
I will go ya halves if ya want.
I also swapped the basic as bricks carby today for a pocketbike one. Straight swap fitment and it will run sweet. Swapable jets, proper adjustments, etc.
Mate, just do the whole thing, I picked up a couple of expansion chambers today. Last time I bought a roll of exhaust wrap there was enough for 2 sets of pipes with some spare.
I will go ya halves if ya want.
I also swapped the basic as bricks carby today for a pocketbike one. Straight swap fitment and it will run sweet. Swapable jets, proper adjustments, etc.
Sorry to go off topic, but where and what carb?? I've got a walbro at home but to get it on the bike is way more than just a straight swap fitment.
To get the most out of these engines a carb uprgrade is essential. The top speed bogging is really starting to annoy me now! The jets are too small, and for the expansion chamber to work at its best then I have to get more fuel in there!
Okay, pretty much all watercooled pocketbikes run a chinese clone of the Dell'orto SHA carb.
Mines a genuine one but the chinese clones are identical.
They are a direct swap part for the horrible stock carb that comes with the happy time.
But you have all the usual adjustments found on a normal carby. And to adjust the mix you just take the 2 screws out of the bottom of the carb and there are screw in jets, standard Dell'orto jets are used and they fit in the chinese clones too.
As the shots show, its childs play to put a proper carby on these engines.