quick qt50 questions

Jake Dachel /

where is the main jet? what is the stock size? what size should i get if i am boring it out to 54ccs, and putting on a high flow exhaust/air filter? also, how do you get the oil injection tube out of the carb without breaking it...oh yeah, one more: what is the right way to get the piston off and on? i havent tried it yet becuase i dont want to screw anything up

thanks! - Jake

Re: quick qt50 questions

Thomas Malcolm /

It hangs down into the fuel bowl of the carburator, so to get a good look at it, turn the carb upside down and remove the bowl. You'll be staring right at it. Its a brass thing that looks kinda like a thick brass flat-headed screw with a hole in the middle.

Oh, and mind that when you turn the carb over that you don't pour fuel all over yourself. Gas stinks and it won't come off your hands or your carpet.

I dunno what the stock jet is, but there should be a number stamped on the jet, probably between 70 and 90.

The oil injector tube is just kinda plugged onto the nipple on the carb. If its stuck, you might try loosening it by placing your thumbnail between the edge of the tube and the carb and pull outward gently to break whatever goo-seal is between the hose and the nipple. You may try a little spray carb cleaner if you're feeling brave. I dunno if that'll melt the hose or not tho.

I can tell you that you can get the aluminum head off without too much effort. Just unscrew the nuts on the head bolts and pull carefully. Be carful not to tear the little lead gasket between the head and iron block. Sure, you can order a new one at your local motorcycle shop, but why? If you don't tear it, it can be reused.

I haven't figured out how to get the iron block off yet (mine's stuck), but I'm trying to get a fella around here to tell me, so I'll let you know if I find anything out.

Removing the cylinder

Michael Miehle /

once the head is of the cylinder should come off by pulling on it. Cycle the engine slowly and it should come off. To break a siezed engine I remove the studs and cycle the engine enough to get to slide out with the piston if it is TDC then skip that step. Put copious amounts of oil in the cylinder breakfree wd40 what ever you have that will penetrate. I use a large socket that will completely fill the cylinder without touching the cylinder wall, with the socket upside down. Then put a slightly smaller socket into it right side up. Then I bash and smash it with a hammer. I'm kidding just hit it gently at first, slowly increase the amount of strength you hit it with until the piston starts to move. draw a line with marker or grease pencil on the socket so you can see when it goes in. when you begin to reach BDC or if you siezed below TDC you must pull the studs then slip the cylinder out of the engine and put nuts big enough for the stud to go through with out threading but small enough to put the stud back in. One nut on each stud. Then pres the cylinder block back in until each bottoms out on the nuts. continue tapping down and adding nuts until the piston is free and clear. Throw piston in the trash and buy a new one. Take the cylinder to the machine shop to be resurfaced. Bring the new piston so they can hand fit it for you.

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