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Post by 50cc on Feb 3, 2013 4:04:11 GMT -5
Hi, in winter my MPG decreases with up to 10 miles. In summer I get 96 MPG, in snow and ice I get 86-88. Running a #75 mj now and I want to decrease it even more. So what do you recommend as the smallest yet SAFE size for a stock 50cc with a free flow filter? I don't want to run it too lean though.
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Post by millsc on Feb 3, 2013 10:14:03 GMT -5
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Post by Enviromoto on Feb 3, 2013 11:20:38 GMT -5
75 main with a free flow filter is kinda lean as is imo.
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Post by prodigit on Feb 3, 2013 19:15:39 GMT -5
I'm an advocate of Hi Oct fuel (93), because my bike is running rather hot, and it helps against pre-detonation.
I know that premium fuel is not the solution for every bike out there.
However, if you're running very lean, it might help somewhat. Try decreasing your jet size, and switch to BP Premium fuel, and see if the bike performs better or not.
I also noticed a decrease in MPG in winter. Not only because it's colder, but also because gas stations change their fuels in colder climates.
Check your spark plug for any unusualities (like getting white, or even melting).
When it's melting, it's usually due to pre-ignition on the compression stroke.
In such case you HAVE to change to a higher octane fuel.
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Post by super9 on Feb 4, 2013 9:37:04 GMT -5
start with the biggest jet and work down while doing plug chops but with that free flow air filter dont expect to go to low or your risk a seize
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Post by Pony66 on Feb 4, 2013 12:14:25 GMT -5
I wouldnt get a smaller jet. Your pilot jet is kinda large. You might drop to a 35 pilot and bump the main up to 80 or so.
The best thing for MPG is to make sure your tires are fully inflated.
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Post by rae4180 on Feb 4, 2013 18:21:20 GMT -5
in the cold and wet you dont wana ride with a open air filter.
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Post by kyle401 on Feb 6, 2013 18:35:12 GMT -5
You may get better gas mileage now but running a bike that lean can have some consequences later. Like the valve stems will wear MUCH quicker and your piston will get MUCH hotter. So your bike will not last near as long.
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Post by OverReved on Feb 11, 2013 3:54:37 GMT -5
My bike comes stock with a 72 Jet and people have ridden them unmodified and no major component replacement for 30K miles. Pop in a 72 and look at your plug.
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Post by lovemy2strokes on Feb 11, 2013 10:25:45 GMT -5
Colder it is the more O in the CO2 and it makes your engine run leaner and hotter. Leaner it is the less gas mileage youre going to get due to loss of power on these already lean running engines.
Burnt and melted pistons cost more than gas, if you want to get better gas mileage put your stock air box back on. You shouldnt be running an open air filter and swap to lower jets, it works the other way, do as you like but Id be saving those few extra pennies for when it blows up.
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Post by rae4180 on Feb 11, 2013 10:58:43 GMT -5
you can drill holes in the stock air box and go up to a 85 main jet.
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Post by prodigit on Feb 11, 2013 11:48:26 GMT -5
Colder it is the more O in the CO2 and it makes your engine run leaner and hotter. Leaner it is the less gas mileage youre going to get due to loss of power on these already lean running engines. Burnt and melted pistons cost more than gas, if you want to get better gas mileage put your stock air box back on. You shouldnt be running an open air filter and swap to lower jets, it works the other way, do as you like but Id be saving those few extra pennies for when it blows up. Actually, Colder weather compresses the air (makes it denser or heavier), resulting in more air overall in the engine; thus also more O2 molecules. However you can live in the winter in NY, or in the summer in the Brasil Rain forests, and have about the same amount of O2 in your engine, depending on how rich the environment is in O2, as well as the temperature, or what kind of weather, or the altitude you're riding in. Those differences in temperatures make very little difference in A/F ratio. Just about as much as riding in a low pressure front (usually rainy), or a high pressure front (sunny); when riding at sea level, or a few tens of feet above sea level; riding on a rainy day, or a sunny day. An open air filter usually also gives very little performance edge over most stock scooter air filters. |
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Post by 50cc on Feb 11, 2013 12:27:40 GMT -5
I put my box back on after some mud snapped on my filter, I tried to clean it without removing it and the damn thing just fell off its hose!! Never again a cheapo filter.. or ANY aftermarket filter!
The weird thing is with the air box the scoot doesn't run with anything below #85 and it's recently oiled and the box itself is not modified.
Anyway, I lost the cool sound, but now the engine itself sounds.. uum... *healthier* I guess.
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