how to increase mpg

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videomandw

New Member
Jun 24, 2010
25
0
0
indiana
hello,

i recently built a scwinn cruiser r.ly.with a chinese 2 stroke on it. i think i'm only getting about 56 mpg. does your mpg increase much after the break in period? what tips might you have on how to increase mpg? is there some adjustment you can make to the carb to increase mpg? someone in this forum said the little screw on the carb is not for the mixture but for idle speed. is that true.

any tips on how to increase mpg would be appreciated. otherwise my little happy time runs great and i'm having a blast riding her.

david
valparaiso, indiana
 
Kevlarr

Kevlarr

New Member
Jul 22, 2009
1,628
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Mi
There are a lot of variables when it comes to MPG. Your weight, the final drive ratio, fuel/oil mix and finally how broken in an engine is.

A lot of people follow the instructions that tell you to run 16:1 oil DON'T! Those instructions are written assuming you're using 30W motor oil not 2 cycle oil. A good ratio to start out with on regular off the shelf 2 cycle oil is 25:1 for a few gallons then cut it to 50:1.

An finally a sure fire way to dramatically increase your mileage is to ride downhill as often as possible. :D
 
Mac

Mac

New Member
Dec 3, 2009
486
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Maine
Yes, if your running a stock carb, the screw on the left side is for idle speed, there are no mixture adj screws, HOWEVER, make sure the jet is the right size, #70 drill bit or .026, real small, see "norms 2 stroke repair" thread for re-drilling procedures and pictures. The bike will not get 150mpg at WOT(wide open throttle) maybe close if your just crusing.
 
V

videomandw

New Member
Jun 24, 2010
25
0
0
indiana
hello,

yes, i have had quite a bit of smoke. i had been running a 16:1 mix to break in the motor, but now i am running about a 25:1. think that heavier mix would decrease my miles per gallon? any other ideas on how to increase mpg. is that true that you can somehow raise or lower the needle pin in the carb to increase mpg? how would i do that? would that decrease performance by a lot if i did it?

thanks in advance for any suggestions,
david
valparaiso, in
 
bairdco

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
16:1 is too rich. that ratio was from when they used 30weight motor oil. i really wish they'd update those instructions...

after a few tanks you can go up to 32:1 or even 40:1 with a good quality oil. mileage should definitely increase.

the needle-clip setting determines how rich your mixture is going into the carb. raising the clip up leans it out, lowering enrichens it.

with the motor cold, pull your spark plug out and check the color. if it's black and oily, raise the needle clip up a notch. ride it around for a day, check it again. ultimately you want a nice cocoa coloured plug.

basically, sounds like your motors just not dialed in yet, that's why you're getting poor mileage. once you figure out how to get it running right, it'll increase.
 
Kevlarr

Kevlarr

New Member
Jul 22, 2009
1,628
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Mi
Being in Indiana 2nd grove from the top is a pretty good bet as to where to have the clip on the needle. Where I am the elevation is about 600' above sea level and the 2nd notch works perfectly. The higher you go in elevation the lower the needle needs to be. I think the top notch is for people who live in Death Valley. lol
 
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