Totally pointless- adding power and efficency to a 66cc chinese bicycle moped... - Page 2 - Fuelly Forums

Click here to see important news regarding the aCar App

Go Back   Fuelly Forums > Fuel Talk > Motorcycles
Today's Posts Search Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 07-26-2009, 08:11 PM   #11
Registered Member
 
kamesama980's Avatar
 
Join Date: Nov 2007
Posts: 742
Country: United States
Location: Columbus, IN, USA
Send a message via AIM to kamesama980 Send a message via Yahoo to kamesama980
chinese engine= blow up soon enough without trying to do so.
__________________

__________________
-Russell
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"
kamesama980 is offline   Reply With Quote
Old 08-13-2009, 03:59 PM   #12
Registered Member
 
Join Date: Oct 2007
Posts: 211
Country: United States
Having had a number of 2 strokes, in stock configuration they are made to go through every kind of weather and traffic conditions without hassle. Also the economics of factory assembly, the cheaper the scoot, the more cost savings went into its production.

In the 80's I had an RD250 Yamaha twin 2 stroke. I replaced the cylinders and pistons with 350 units, added a DG head that raised the stock compression from 7.4 to 9.5 to 1, added Bassani expansion chambers for exhaust, swapped the 28 mm carbs for 34 mm carbs. In the end it had the power of a 900 cc bike. The trade off was I went from 42 mpg to 18 mpg !!! With help from my local Yamaha dealer, he showed me how to jet it leaner, play with needle sizes in the carburators to get the bike back some MPG. After that I got between 28 to 34 MPG, that was liveable.

With allot of the scoots out there especially the 50 cc class, a pipe and carb will will raise your upper RPM and that way increase your speed, because you can't change your final drive ratio. If you check out Mopedarmy.com, they have dozen of stories. Youtube more than likely has your scoot modified, and you can follow the trail to see what they did.

With your bike, if you can get a Mikuni carb kit for it, that may be better than the stock carb by providing better atomization of the fuel. If you do add an expansion chamber, limit if you can the exhaust outlet size. An expansion chamber works like a reverse supercharger, the chamber creates a vacuum effect, making the exhaust pressure lower, drawing in a larger volume of fuel. If you have ever added an expansion chamber to a stock bike, its a rush, once up in the RPM band, the expansion chamber goes into action and the bike leaps away. To cover all this extra power, you have to add fuel, therby making your MPG go down.

Defentely go out and play, tear it appart, its a tone of fun. I don't know if there is an 80cc kit for it, it would be interesting to see how many after market perormance parts would make better MPG. Little things like advancing the spark a degree or two might make better MPG, advance it too much and you'll overheat, overheating a 2 stroke means seazing the piston.

Taking the cylinder head and milling it down a millimeter could give you a bump on compression, there is some more MPG. Going to a Bosch platinum can help. A pile of little things can add up to a big thing. Enjoy.
__________________

GasSavers_Scott is offline   Reply With Quote
Old 08-13-2009, 04:04 PM   #13
Registered Member
 
Join Date: Oct 2007
Posts: 211
Country: United States
Oh yeah I forgot, if your scoot has a variator, or variable transmission, you can remove or sand down the limiting washer on the engine side of the drive pulley, with this it will make the cones come closer together and raise your final drive ratio, making your gears taller by 1 or 2 percent.
GasSavers_Scott is offline   Reply With Quote
Old 08-13-2009, 04:48 PM   #14
Registered Member
 
DarbyWalters's Avatar
 
Join Date: Oct 2007
Posts: 376
Country: United States
A medium/low ported 2 stroke will give more pull down low and allow a lower rpm for normal cruising.
__________________

__________________
2006 Jeep Liberty CRD...Founder of L.O.S.T.
OME 2.25" Lift w/ Toyo Open Country HTs 235/75/16s
ASFIR Alum Eng/Tranny/Transfercase/Fuel Skids
2002 Air Box Mod...Air Tabs (5) on Roof...(3)each behind rear windows
Partial Grill Block with Custom Air Scoop and 3" Open Catback Exhaust
Lambretta UNO150cc 4 Stroke Scooter



DarbyWalters is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Fuelly Android Apps
Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 12:58 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.