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Post by plecko on Jun 19, 2018 16:51:02 GMT -5
I need help I been trying so hard to figure out what's going on with my moped I usually fix it my self since the guy we take it to closed down a nd everyone else charge so much.
What's happening is I will start it and it will drive fine for like 10 min or maybe till it really heats up not sure why it starts but it will have power when I first start it then after a little I will lose power going from 40 all the way down to 30 and sometime it will even hit 20 like really slow and stay there the whole ride no matter what I do it sucks cause people trying to pass me and it's my only way to work. It also starts to feel pull back or boggling when I get up to past 30 it will start to pull back every couple of seconds like something trying to stop it but it only happens when I get at 30 or higher , other then that it will run and start fine it just started acting out one day out the blue it's a little hot out side but it's been fine for a long time in the heat till now? I have checked the valves I have changed the belt waights and variator, I have taken off the carb and cleaned it the jets and what not I have changed the spark plug . I can't figure out what's going on it will run fine some times but when going up a little hill I'll lose power so bad and it will stay that way the rest of the ride but when I first start it it's fine and runs not as fast as it use to but decent can anyone give me any ideas. Was thinking maybe something wrong with position but wouldn't explain why it runs fine sometimes.
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Post by KSR Moto on Jun 19, 2018 16:56:30 GMT -5
Omg something similar is happening to me, cant figure it out!
Is this on a gy6 50?
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Post by plecko on Jun 19, 2018 18:51:26 GMT -5
Yea it's on a 50cc out a boar kit in it but no problems till recent and idk what gy6 means
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Post by scootnewb on Jun 20, 2018 16:58:16 GMT -5
gy6 is the kind of engine.
Did you guys figure out what was causing this?
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Post by plecko on Jun 20, 2018 17:23:18 GMT -5
No haven't yet no ones replied knowing what's wrong do u know ?
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Post by scooterted on Jun 20, 2018 19:44:36 GMT -5
While the engine is hot and acting up check for fuel flow to the carb and compression of your engine. I might even just replace the fuel lines themselves.
Hows your fuel mixture? Not too lean?
Youre certain your valve lash is correct?
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Post by plecko on Jun 20, 2018 22:00:49 GMT -5
Yea I'm sure I do the valves correct any I use 91 in fule and my gas lines are solid thick tubes idk what else it could be Ives checked everything it runs and it's just a bit slower but only really noticeable when going up a small hill then it get so bad and stays there
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Post by scooterted on Jun 21, 2018 6:24:46 GMT -5
You say solid thick fuel tubes. But is there anything obstructing them inside?
Have you checked engine compression?
Is there an rpm difference with your power loss?
What specifically is yout valve lash set at?
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merrikii1
Scoot Member
Posts: 75 
Location: SE SC
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Post by merrikii1 on Jun 21, 2018 6:49:03 GMT -5
This happened to me when I had the rockers too tight.
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Post by scooterted on Jun 21, 2018 7:14:07 GMT -5
This happened to me when I had the rockers too tight. It really sounds like this is the issue. Can you (the op) specify what your valve lash is set at? And perhaps go a little looser just to test? |
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Post by GrumpyUnk on Jun 21, 2018 8:42:00 GMT -5
Is the problem heat/temperature related or 'time' related(happens after running xx minutes)?
If temperature, I'd look at the valve clearance. Clearance will close up more with heat, and cause low compression.
If time, I'd look at the fuel supply. Fuel supply might just be a bit too slow for higher speed operation, and then not catch up until enough has leaked past the restriction into the float bowl.
You can check the clearance with the engine cold, crank at TDC, cam with the two holes level with the top of the head, single hole at Top or bottom(machs nix). You should be able to feel the rockers move just a slight bit, using .002" for IN and .003" for EX should allow for normal expansion and work OK.
When it starts to lose power, do two things: Stop the engine and see how hard it is to crank it over. If it cranks slowly, you have a friction or overheat problem occurring. If it cranks easy, you have a loss of compression problem. If it cranks normal, I'd be looking at the fuel supply.
tom
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Post by pinkscoot on Jun 21, 2018 8:54:58 GMT -5
Are you adjusting the valves when they are cold? I mean sat overnight cold.
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Post by KSR Moto on Jun 21, 2018 10:04:33 GMT -5
Is the problem heat/temperature related or 'time' related(happens after running xx minutes)? If temperature, I'd look at the valve clearance. Clearance will close up more with heat, and cause low compression. If time, I'd look at the fuel supply. Fuel supply might just be a bit too slow for higher speed operation, and then not catch up until enough has leaked past the restriction into the float bowl. You can check the clearance with the engine cold, crank at TDC, cam with the two holes level with the top of the head, single hole at Top or bottom(machs nix). You should be able to feel the rockers move just a slight bit, using .002" for IN and .003" for EX should allow for normal expansion and work OK. When it starts to lose power, do two things: Stop the engine and see how hard it is to crank it over. If it cranks slowly, you have a friction or overheat problem occurring. If it cranks easy, you have a loss of compression problem. If it cranks normal, I'd be looking at the fuel supply. tom I tried wainting to see if my carb bowl would fill up but it is not a fuel issue, it is more temperature related but I am using .002 for intake and .003 for exhaust... Still stuck with this, compression is good both hot and cold |
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Post by KSR Moto on Jun 21, 2018 10:05:38 GMT -5
Are you adjusting the valves when they are cold? I mean sat overnight cold. Valves adjusted on stone cold engine, nothing changes |
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Post by jackrides on Jun 21, 2018 11:03:00 GMT -5
Basic, but next time it happens, remove the gas cap, put it back on, and see what happens.
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