thanks im gonna get a new pipe do you have any suggestion ?
Remove the spark plug and put a length of solder in the hole, turn the engine over while holding the down end of the solder against the cylinder wall. Remove the solder and measure how much the piston squished the solder. That # should be between .7-.8mm. If your piston comes up flush with the deck and your not at the desired thickness, then you have to plane down the head or use a thinner head gasket. If the piston is lower than the deck, you can plane down the top of the jug or use a thinner base gasket.
If you have the head off already, then you can tape a length of solder that spans the full width of the piston on top of the piston, install the head and turn over the engine.
Can you weld and cut metal? or are you limited to off the shelf?
i have the tools too i just dont have any experience
Get a dirt bike pipe, small 80cc ( I mod mz65's into the KS65, look on here in the search to see my work, lol, an I'm going to be working on a cr80 pipe soon ) works well, look up how to tune the pipe for what you want. It's just some math for length and width etc, not to hard since the chamber is already made for you. Do as chainlube said, and if it's not in the right zone, shave from the top of the jug how much it is off. Before doing that, make sure your piston uncovers the ports, if not, add gaskets till it does. then measure squish and set. a quick balanced crank is as easy as drill 6 holes the right depth at 12mm wide. I'm assuming you've already cleaned the ports. You can widen them if you want, but don't change the height, make them kinda football shaped. American football.
seems like getting a dirtbike exhaust might just be harder than getting a new one since there is no junkyard in my city do you have any off the shelf option ?
