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Post by blueodyssey on Jul 16, 2019 10:36:36 GMT -5
So I have a 50cc geely 2017 scooter. It's the qmb139 motor. I recently put a 100cc big bore kit on and when I got it back together it didnt have compression. Well I fixed the compression and got it started but whenever I give it gas it starts popping. The carberautor came with a stock #73 jet and I have put a #  jet in it and it's still doing it. Does anyone know what could be happening? |
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Post by tortoise on Jul 16, 2019 11:10:37 GMT -5
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Post by blueodyssey on Jul 16, 2019 11:16:22 GMT -5
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Post by blueodyssey on Jul 16, 2019 11:16:52 GMT -5
It's the jl50qt-13 model
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Post by jaciche on Jul 16, 2019 11:18:52 GMT -5
Seems like it's running lean. What size main jet did you put in the carb?
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Post by blueodyssey on Jul 16, 2019 11:24:35 GMT -5
#8 8 it came with a #73
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Post by blueodyssey on Jul 16, 2019 11:25:20 GMT -5
its an now idk why it put an emoji? |
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Post by ryanqzqz on Jul 16, 2019 22:39:31 GMT -5
With a "100CC" you need to up that jet sir. Common word on the interwebs is to bump up to an # or better. I'd say run a  and make a few high speed runs and pull your plug and see if you're REALLY rich, or just a little rich. I like mine a TINY bit rich just to keep things cool. Right now I'm running an #  and it's a might bit lean, but I'm running stock intake, and checking some CVT upgrades before I re-jet. But I have a "100CC" BBK and a 19mm carby, and 1500 contra/clutch springs. Stock rollers. With my factory #75 things were REALLY freaking lean, and power sucked. |
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Post by ryanqzqz on Jul 16, 2019 22:39:51 GMT -5
I hate emojies
Make that a # 8 8 and then a # 9 0 and then a # 8 5
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Post by ryanqzqz on Jul 16, 2019 22:44:04 GMT -5
Or i could read where you said you are running an # 8 8 ........ Where do you hear the popping if you put it on the center stand and rev it up, exhaust? or intake?
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Post by blueodyssey on Jul 17, 2019 9:14:12 GMT -5
I'm not really sure I would assume it sounds like it's from the intake if I had to guess tho.
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Post by blueodyssey on Jul 17, 2019 9:19:42 GMT -5
I do know I had an #8 5 in there and it was still popping but it wasnt loosing power now I where I put the # 8 8 in whenever I do a wide open throttle it's like its bogging down. It'll start loosing power
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Post by jaciche on Jul 17, 2019 9:31:21 GMT -5
Then it sounds like the 8 8 jet is too rich at WOT. The popping noise could also be an air leak somewhere along the intake or the exhaust system. If you wore out any rubber grommets, gaskets or anything, they need to be replaced or repaired so they make a tight seal. These engines are sensitive to air and exhaust flow. Is the stock exhaust still on there?
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Post by chewbaca on Jul 21, 2019 23:19:36 GMT -5
if its popping that means it is running rich and that there is an exhaust leak
unless it's only popping at no throttle deceleration then it probably only an exhaust leak
a lean running engine will not pop in the pipe because there is no fuel left to burn
and an exhaust with no leaks will not pop because any fuel in the exhaust will have cooled
below ignition temperature before exiting the exhaust
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Post by blueodyssey on Aug 1, 2019 14:46:23 GMT -5
So I took my moped to a shop and they told me that the timing and everything was good they adjusted the valves for me. The said the popping is coming thru the carberautor and they reccomend just getting a bigger carburetor. What kind of carb should I get
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jet in it and it's still doing it. Does anyone know what could be happening? 
and make a few high speed runs and pull your plug and see if you're REALLY rich, or just a little rich. I like mine a TINY bit rich just to keep things cool. Right now I'm running an #
and it's a might bit lean, but I'm running stock intake, and checking some CVT upgrades before I re-jet. But I have a "100CC" BBK and a 19mm carby, and 1500 contra/clutch springs. Stock rollers. With my factory #75 things were REALLY freaking lean, and power sucked.
