so, i got a new carb, ordered it off of ebay. Its a cheap china carb for 80-100cc scooters. first problem i had with this carb was it was to bid to mount on the manifold. this was remedied with a smmall piece of pvc and some good ole fashion human ingenuity.
once i solved that problem it was on to the throttle cable, the stock cable didnt extend out of the sheathe long enough for the slide to sit at idle, as well as the stock twist throttle didnt move the cable enough. solved this with a twist throttle/killswitch from a dead yamaha rt180 works extremely well, just have to do something about the extra cable (originally used for oil feed, 2 stroke dirtbike)
my sweet new exhuast is off of a suzuki 50cc atv. has a bigger port and a rather small but noticeable expansion chamber that was U shaped and about 1'' in diameter and 6 inches from flange to pipe. i cut a few bend out of the pipe and then welded it back onto the exp. chamber. i shortened the pipe a bit to much so now my heall its the back of the muffler and my toes hit the expanion chamber from time to time. i welded a bolt to my bike frame to secu the muffler in the back, using a nut combo to hold it in place.
i installed the carb and tuned it and ran it for a little while, more responsive but no other noticable gains.
i installed pipe and had to tune the carb once again, still working on it, as i lean it out it starts racing and trying to die, if i richen it up, it doesnt get that smooth sweet spot that 2 smokers have when im at high RPM. but through out the range otherwise pulls great and has that nice smooth sound. it baffles me.
im also wondering if i should cut the pipe and weld in a washer at the back of the exp. chamber to get a little more back pressure, the pipe seems too free flowing and the engine is pinging quite a bit with the exhaust the way it is now. I have been running running 40:1 with no pinging or anything like that, i really think it just lacks a little back pressure.
opinions and ideas, welcome.
Pics coming soon (when there is daylight)
Moosinatrix
once i solved that problem it was on to the throttle cable, the stock cable didnt extend out of the sheathe long enough for the slide to sit at idle, as well as the stock twist throttle didnt move the cable enough. solved this with a twist throttle/killswitch from a dead yamaha rt180 works extremely well, just have to do something about the extra cable (originally used for oil feed, 2 stroke dirtbike)
my sweet new exhuast is off of a suzuki 50cc atv. has a bigger port and a rather small but noticeable expansion chamber that was U shaped and about 1'' in diameter and 6 inches from flange to pipe. i cut a few bend out of the pipe and then welded it back onto the exp. chamber. i shortened the pipe a bit to much so now my heall its the back of the muffler and my toes hit the expanion chamber from time to time. i welded a bolt to my bike frame to secu the muffler in the back, using a nut combo to hold it in place.
i installed the carb and tuned it and ran it for a little while, more responsive but no other noticable gains.
i installed pipe and had to tune the carb once again, still working on it, as i lean it out it starts racing and trying to die, if i richen it up, it doesnt get that smooth sweet spot that 2 smokers have when im at high RPM. but through out the range otherwise pulls great and has that nice smooth sound. it baffles me.
im also wondering if i should cut the pipe and weld in a washer at the back of the exp. chamber to get a little more back pressure, the pipe seems too free flowing and the engine is pinging quite a bit with the exhaust the way it is now. I have been running running 40:1 with no pinging or anything like that, i really think it just lacks a little back pressure.
opinions and ideas, welcome.
Pics coming soon (when there is daylight)
Moosinatrix
