Motorized Bicycle Engine Kit Forum  

Sponsors



Go Back   Motorized Bicycle Engine Kit Forum > Bicycle Motor > Motorized Bicycle Trouble Shooting

Motorized Bicycle Trouble Shooting Use this area to post problems that may arise, if you could use some help in figuring out what is wrong with your engine and what needs to be done to achieve top performance.

Reply
 
Thread Tools Display Modes
  #1  
Old 10-11-2010, 04:37 PM
WaterDog's Avatar
WaterDog WaterDog is offline
Motorized Bicycle Senior Member
 
Join Date: Sep 2010
Location: Miami / Fort Lauderdale, Florida
Posts: 59
Default running rich or lean??

Ok, my bike runs fine, well I assume so because I've only rode my own. Low and mid range acceleration is great, but it seems to hit a wall near the top end. It almost feels like a limiter is installed or maybe the engine chokes a little. I ran out of gas today and had incredible power and speed between the sputtering. So I assume I had a temerary lean condition (lean means more air correct?). So I was wondering how I can adjust my lean/rich mixture to find the ideal ratio. Is there a screw or something similar to the idea speed screew? I do have the high flow K&N style air filter and regular muffler.
Reply With Quote
  #2  
Old 10-11-2010, 04:54 PM
Bikeguy Joe Bikeguy Joe is offline
Godfather of Motorized Bicycles
 
Join Date: Jan 2008
Location: up north now
Posts: 11,531
Default Re: running rich or lean??

Sounds like you are rich on the top end. If it four strokes when wide open near top rpm, and runs way better when you run out of gas, it is generally too rich. Only a "plug chop" will tell fo'sho'. Clean the plug thoroughly, then put it in, and after warm up run it wide open for a minute or so if you can stand the vibes, then pull the clutch and cut the engine off.

If the plug is black/wet/oily, you are too rich.
Reply With Quote
  #3  
Old 10-11-2010, 05:08 PM
WaterDog's Avatar
WaterDog WaterDog is offline
Motorized Bicycle Senior Member
 
Join Date: Sep 2010
Location: Miami / Fort Lauderdale, Florida
Posts: 59
Default Re: running rich or lean??

thx...ok, so once I determine rich or lean, how do I correct it? The engine is relatively new so I am running 25:1 synethic right now. Is there an adjustment screw or how exactly would I adjust the rich/lean?
Reply With Quote
  #4  
Old 10-11-2010, 07:07 PM
Nougat Nougat is offline
Motorized Bicycle Elite Member
 
Join Date: Nov 2009
Location: Montgomery, IL
Posts: 1,332
Default Re: running rich or lean??

Unscrew the carb top and remove the throttle cable from the slide. There's a long pin - the needle - with a little e-clip on it. Stock, that clip is in the middle of five notches. Move it to the second notch from the top. This lets the needle sit lower in the emulsion tube, which has the carb run leaner between about 20 and 80 percent throttle.

The only way to make it leaner at full throttle is to replace the jet with a smaller one.

If you're still breaking in, I wouldn't worry about it too much. Wait till you've got a couple hundred miles on.
__________________
When asking for advice, you did not specify whether you wanted only good advice.

Get on the motorbicycling.com member map

Reply With Quote
  #5  
Old 10-11-2010, 07:22 PM
WaterDog's Avatar
WaterDog WaterDog is offline
Motorized Bicycle Senior Member
 
Join Date: Sep 2010
Location: Miami / Fort Lauderdale, Florida
Posts: 59
Default Re: running rich or lean??

Perfect, ill try adjusting the e-clip. But considering it runs pretty good in the 20-80% of throttle, maybe the jet could stand some adjusting. Wouldn't it just be better (and easier for a newbe) to buy the racing carb? They're not that pricey and I assume these mods have already been done.
Reply With Quote
  #6  
Old 10-11-2010, 07:26 PM
Dave31's Avatar
Dave31 Dave31 is offline
Super Moderator
 
Join Date: Mar 2008
Location: Old Pueblo,Arizona
Posts: 11,127
Default Re: running rich or lean??

You will still need to tune it for your engine, some get lucky just bolting them on but chances are you will still have to do the same thing.

I tune my carb using the needle and jet. I also tune for 1/4, 1/2, 3/4 and full throttle to get the best performance.
Reply With Quote
  #7  
Old 11-09-2011, 01:32 PM
isthisreal1991 isthisreal1991 is offline
Motorized Bicycle Newbie
 
Join Date: Oct 2011
Location: upstate NY
Posts: 13
Default Re: running rich or lean??

I know I'm a little late but I have questions... I just signed up for this thread and I'm having the EXACT same problems but IM a noobie so I need more help and I can't figure out how to post a thread on this site for this please help me mainly on how to make a new tread I can't figure it out.
Reply With Quote
  #8  
Old 11-09-2011, 07:01 PM
decoherence's Avatar
decoherence decoherence is offline
Motorized Bicycle Elite Member
 
Join Date: Aug 2010
Location: sebring,fl
Posts: 476
Default Re: running rich or lean??

Quote:
Originally Posted by isthisreal1991 View Post
I know I'm a little late but I have questions... I just signed up for this thread and I'm having the EXACT same problems but IM a noobie so I need more help and I can't figure out how to post a thread on this site for this please help me mainly on how to make a new tread I can't figure it out.
you know where you clicked "new post"?
one page back in the same spot is "new thread".

if you have the same problem, the answer given above is pretty much simplified instructions.
no need to start a new thread.
what part do you not understand?
that part can be explained further.
if you want to know something like the "plug chop" mentioned, you can use the custom search @ the top.
just enter plug chop.
it will pull up relevant posts.
most questions have been covered many times & can be quite helpful.
Reply With Quote
  #9  
Old 11-11-2011, 03:55 AM
Maxvision's Avatar
Maxvision Maxvision is offline
Motorized Bicycle Elite Member
 
Join Date: Jun 2009
Location: San Diego, CA
Posts: 551
Default Re: running rich or lean??

Quote:
Originally Posted by WaterDog View Post
Ok, my bike runs fine, well I assume so because I've only rode my own. Low and mid range acceleration is great, but it seems to hit a wall near the top end. It almost feels like a limiter is installed or maybe the engine chokes a little. I ran out of gas today and had incredible power and speed between the sputtering. So I assume I had a temerary lean condition (lean means more air correct?). So I was wondering how I can adjust my lean/rich mixture to find the ideal ratio. Is there a screw or something similar to the idea speed screew? I do have the high flow K&N style air filter and regular muffler.
One way to tell if you're running rich or lean is to run you bike full throttle for a while then shut the motor off and look at the spark plug. Black plug = rich, light tan = lean, light brown = just right.

I run my bikes lean causer I love to hear them scream. But I go through lots of head gaskets and cylinders.
__________________
- What if the Hokey Pokey's REALLY what it's all about! -
Reply With Quote
  #10  
Old 11-12-2011, 05:41 PM
isthisreal1991 isthisreal1991 is offline
Motorized Bicycle Newbie
 
Join Date: Oct 2011
Location: upstate NY
Posts: 13
Default Re: running rich or lean??

haha i still cant find out how to post... but um yea so my plug is always covered in oil i dont know if im confident enough to take a part the carb to mess with the needle and also i have the upgraded carb for the 66/80 cc with no primer just one screw on one side which i belive is idle and 2 really small scres on the other side and i dont know how to tinker with them ... after 4 min of running if i WOT it boggs i can do about 60% throttle on flat ground
Reply With Quote
Reply

Thread Tools
Display Modes

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



All times are GMT -5. The time now is 10:35 PM.


Sponsors

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
MotorBicycling.com