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Post by dmartin95 on Aug 26, 2014 15:13:55 GMT -5
Hi, New member here. Thank you all for such a wonderful site. Now for my issue. I have a 20008 150cc Lance vintage with a gy6 short case clone. Today wile driving it @ 45 mph for 5 minutes it started sputtering like it was cutting in an out. I slowed down on the side of the road and it ran fine at 30 mph for a couple of minutes then I was able to continue cruising at 45 with no problems for a few minutes. But anytime I ran it for more than 5 minutes at that speed it would start to do the same thing. Now last nite I took her out and was able to cruise at 50 for as long as I pleased with no problems. Hi, I'm a new member here also and my wife has a 150cc BMS Heritage, it looks identical to the one in your picture. Her scooter is exhibiting the same symptoms as your scooter.... Long cruises at wide open throttle causes the engine to cut out, but only momentarily... She can back off the throttle and bring it back to normal. Her scooter is in brand new condition with only 300 miles on it. Suffice to she, it does have the exhaust .  |
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Post by alleyoop on Aug 26, 2014 15:47:40 GMT -5
Dmartin95, Yours sounds like it is just running lean at Wide Open Throttle since you can back off a little on the throttle and it settles down. So turn the fuel ratio screw Counter Clockwise 1/2 turn and see if that helps. Alleyoop  |
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Post by xyshannen on Aug 26, 2014 19:16:17 GMT -5
Thank you Seamus I would have never thought to look there.
Thank you Leo, as luck would have it I have a bunch of electrical conduit laying around and it's a perfect plug in fit to the header pipe. A quick test ride and it's noticeably quieter and does a lot less popping when coming to a stop.
dmartin, I know there are several scooters like mine with different badges. All basically the same bike just sold under different names. one of our fellow members here rockynv also had a 2007 and this is what he said reg the fuel system on these things.
"More critical to top speed was maintaining good fuel flow with the gas tank under the floorboards as the vacuum fuel pump needs to be clean and have a good vacuum source and get a solid intake pulse to make the diaphragm inside flutter and pump enough fuel to keep the engine running at speeds over 50 mph or while climbing a long grade. If the fuel pump can't keep up then the engine will run lean and start overheating leading to a soft seize, burnt piston or burnt valves.
"
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Post by dmartin95 on Aug 26, 2014 23:17:02 GMT -5
Alleyoop - Thanks for the tip! I will try that first opportunity I get.
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xyshannen - The moped is in show room condition. It only has around 300 miles on it and has never seen dirt or rain. It's a very clean scooter and if there's anything impeding the Air, it would have to be the fuel petcock (I don't think mopeds have fuel pumps) itself, or a vacuum line leaking......
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Post by dmartin95 on Sept 3, 2014 1:51:39 GMT -5
Dmartin95, Yours sounds like it is just running lean at Wide Open Throttle since you can back off a little on the throttle and it settles down. So turn the fuel ratio screw Counter Clockwise 1/2 turn and see if that helps. Alleyoop I popped the seat off tonight and yanked the plug. I cross referenced my plug to pictures on web from NGK and champion and it appears to be that my plug is dry fouling indicating it is in fact running lean. Unfortunately I think I have to remove the side panel to tune the carbs air-fuel mixture per your instructions. I wish I had better access to the carb without having to remove the side panel. Anyhow, I snapped some pictures of the plug, take a look and tell me what you think:    |
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Post by JerryScript on Sept 5, 2014 12:33:33 GMT -5
If you can see the carb, you can reach down the side with a shorty screwdriver and adjust the a/f mixture. You may need to remove the side panel the first time to find the screw head, but once you have, put the side panel back on and get used to feeling for it from above so you don't have to remove that side panel again.
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Post by alleyoop on Sept 5, 2014 12:56:28 GMT -5
That plug is to RICH NOT LEAN, that is why it runs good at night when it is COOLER. Motors need more fuel in cool weather and LESS FUEL in HOT weather, So turn the Fuel Ratio Mixture Screw CLOCKWISE to cut some fuel. Try 1/2 turn clockwise and see if it acts better.
Also I missed what you said that if you back off it settles down WHICH is another indicator of it being to RICH. A trick of the trade is if you Back off about 1/8-1/4 on the throttle and hold it there and the scooter SPEEDS UP then it to LEAN, if it just settles down it is to RICH.
Another trick of the trade is if the muffler sounds throaty that is also an indicator of it being to rich, if it sounds tinney it is to lean.
And by the way this trick of the trade works at any throttle position so depending of where a motor acts up you can pinpoint what to adjust, Fuel Mixture, Needle or Main Jet. Providing of course everything is sealed and no air leaks.
Everything can be diagnosed to find what is causing a problem but you have to know how everything works and what each system on a scoot does and the symptoms each will produce if something in that leg of the system is not working right. Then it is just a matter of going down that system testing each part of it to find the culprit.
Alleyoop
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..BAD TO THE BONE..
