How to increase your MPG

Tom

Active Member
Joined
Aug 4, 2006
Messages
1,095
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5
#1
I figure this thread needed to be started. Some suggestions I can come up with: (actually they are just guesses, thats why they have the ? after them all)

new carb?
smaller sprocket?
lower idle?
correct fuel/air mixture?
correct fuel/oil mixture?

always looking for ways to improve

what does everyone else think?
 


B

bird

Guest
#2
running preimum gas instead of unleaded and ive also heard of mixing a little rc airplain fuel gives it a little boost in speed. i wouldnt doubt it tho those things run like above 6000 rpm.
 

S

Steve

Guest
#3
those things run like above 6000 rpm
Bird,

I'm into RC, both airplanes and helicopters, and a typical glow fuel RC engine will turn anywhere from 16,000 to 22,000 RPM. Glow fuel is a mixture of methanol, oil, and nitromethane in varying percentages. Your 2 stroke bike engine will run on it just fine and make lots more power, but your carb needs to be modified so it is about 4 to 5 times richer mixture. The bad news is, glow fuel is selling for from 15 to 30 dollars a gallon, depending on nitro content and where you purchase it.
 

B

bird

Guest
#4
what if you mix it in with regular fuel. some guy told me to do it but i didnt want to throw down a lot of money for a bottle of rc fuel and not have it work. would it make a difference if you mixed it?
 

S

Steve

Guest
#5
Yes, it would make a difference, but again, you need to richen the mixture in relation to how much glow fuel you use, and the improvement in power will be proportional to the amount of glow fuel used. It would give you more power, but your mileage will go down. It's difficult if not impossible to make more power from the same displacement without burning more fuel.
 

J

joeranton

Guest
#6
I think that a smaller rear sprocket may be the answer to better MPG and higher top end speed. Think about it. If you go 20 mph after you have installed a smaller rear sprocket, your engine will run at lower rpms at that same speed. This may actually use less fuel. Please correct me as I may be wrong. Still in the learning stages.
 


J

joeranton

Guest
#8
I would definately say that a lower idle speed could also be a way of conserving fuel. Why run the engine at high idle speed and use more fuel if it is not doing any work. Now I am indeed curious about the correct fuel/air mixture. Wouldn't the engine make more power if it is run lean. After all, if it is not run lean enough, there will not be enough air in the mixture to use to burn the fuel quickly and effectively. However, u probably already know that running it lean will, in most cases, make the engine run hotter. Doing this is probably good for short distance runs though.
 

G

Guest

Guest
#9
RC fuel as well as "super" or "premium" unleaded, not to mention any type of fuel additive aren't going to do anything for you but cost a bunch of money and the RC fuel will screw you up big time if you try mixing it.

A two stroke engine run on alcohol requires almost 3 times the fuel to air ratio.

A smaller rear sprocket will help, but if you run it wide open all the time, it won't help much if at all. Run @ 3/4 throttle and you'll see improvement.

Lowering the idle will help only in a miniscule way.

Running too lean will only cause you engine problems.

Running a mixture of synthetic oil at a more reasonable ratio (something like 40 or 50/1 instead of 20/1 will also help....a little.

A good (NGK, Bosh, Champion) plug, kept clean will go a long way.

Correct tire pressure, lower weight and good aerodynamics will get you better mileage improvements than any magic additive in the tank.
 

D

dwayn3

Guest
#10
joeranton said:
I think that a smaller rear sprocket may be the answer to better MPG and higher top end speed. Think about it. If you go 20 mph after you have installed a smaller rear sprocket, your engine will run at lower rpms at that same speed. This may actually use less fuel. Please correct me as I may be wrong. Still in the learning stages.


I don't think the size of the rear sprocket matters as much as the size of the drive sprocket. My thoughts would be a larger drive sprocket would definately add to speed & reduce consumption.
 

G

Guest

Guest
#11
A larger drive sprocket would in effect be the same as a smaller driven sprocket, just not the same ratio increase per tooth.
 

S

SlicerDicer

Guest
#12
In response to the good spark plugs. I know that on my Audi going from the _elcheapo_ plugs that the previous owner put in.. to the Bosch Platinum 4 way spark. It gave me about 2mpg more on a 4.2 V8. Would it do the same with these? A bigger spark making a better combustion and less wasted fuel?
 


G

Guest

Guest
#14
Good logic Joe.

I find that I get nearly 200 mpg when I run at around 15 mph, pull in and lock the clutch on most hills and use only partial throttle to accelerate.
 

L

locoWelder

Guest
#15
I get about 140+ to a gal, my truck get 6.5 to a gal,so I dont need to save any more gas,but I have found out that on my bike whan I changed out the 5mm plug wire that came with the cdi to a larger automotive 8mm wire and silaconed both ends on that the bike ran alot better. also try a hotter plug.....now on mine bent the arm down and cut and spread the ends to make a redneck splitfire plug works great
 


W

wes

Guest
#17
that's the best advice yet. that's why i like the 25cc zenoah over the 47 tanaka; i get a workout and get there almost as fast. coming from a background of hardcore road cycling, it is my preference to assist. these aren't motorcycles guys. that's why they are more fun!!!
 


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