New member+Bike Questions

[johngreen]

hey! new member here, not new to biking, sorta new to these motors but they're pretty self explanatory.

As of my problem i havent done a ton of investigation which i probably should have done before consulting all of you fine folks.

Problem: i have a nice running (usually) 80cc bike i am running 40:1 mixed myself. My bike is currently awaiting a new spark plug arriving tomorrow because its fouled (think its a NGK B6L.) I think my problem is my petcock or bowl etc. I have a friend who while hes riding leaves his petcock on. If i do this first of all it fills up ands leaks out of the air intake, second if i leave it on the bike eventually sputters down and stops. Then I clutch, turn off petcock and keep riding untill i need to turn it on again once my bowl is used up. One solution I have is to open the petcock slightly which kinda works but im fairly sure that the float is supposed to float up once full and prevent more from entering.

 

[Greg58]

Welcome to the forum, it sounds like you have debris holding the needle open or the float needs adjusting. The stock carb is very simple, I’ll post a link to take it apart.

 

[Greg58]

Here’s the link.

Motorized Bicycle Carburetor install and rebuild

Pictures from taking the carb off the bike and taking it apart to puting it back together and some info. on how and what it all does well sort of and ways to change the min jet for those who want to and areas that can bite you by plugging off and sort of how to fix them. I hope this will sort...

motorbicycling.com

 

[johngreen]

Here’s the link.

Motorized Bicycle Carburetor install and rebuild

Pictures from taking the carb off the bike and taking it apart to puting it back together and some info. on how and what it all does well sort of and ways to change the min jet for those who want to and areas that can bite you by plugging off and sort of how to fix them. I hope this will sort...

motorbicycling.com

thanks for the reading, in the comment before you meant debris would be in the jet end where the needle goes in? also i read the reading and if i were to bend the float things to make the engine leaner and not flood what would be the best way to go about doing that

 

[Greg58]

Take the float out and bend the tang a little.

 

[johngreen]

with pliers, downward i would assume

 

[Greg58]

The tang is the mount arm that holds the needle, it is easily bent with needle nose pliers.

 

[Greg58]

You want to make the float close the needle sooner.

 

[Oldbiscuit]

If you remove the carb, after cleaning out the needle and seat, invert the carb. Install the float with the needle attached. The float should be parallel to the carb body. Bend the tang on the float to achieve this. Reattach the float bowl and install the carb.

 

[Venice Motor Bikes]

Before you take anything apart; do this test!

First... Turn on the fuel until you see the gas pouring out of the air filter.
Next... (while the gas is still pouring out), lift the rear wheel off the ground about a foot or two & drop it hard on the ground!!!
Then keep doing it until the gas stops pouring out of the carb!

Basically, you're trying to shake the carb real hard to unstick the float inside.

If it never stops pouring out?, then do as the others said & clean out the carb.



Also... The correct spark plug is a NGK B6HS / PN# 7534

 

[johngreen]

okay, will bp6hs work and will b6L work

 

[johngreen]

does it matter which way the float is placed in carb, with the ridge ontop or on bottom i mean

 

[johngreen]

i tried to blow air into the fuel intake while manually pushing the tang needle and the air flow was never cut off it was continuous, even letting more air in i pushed the tang

 

[johngreen]

could it be jammed up? im only running the inline petcock filter

 

[johngreen]

cleaned it up and the connection slider was bent out so i rebent it to keep it in it should open and close without issues. still wondering if b6l will work

 

[Oldbiscuit]

Blowing into the gas inlet, can you push lightly on the needle (without the float or linkage attached) and stop the air flow ?

 

[johngreen]

i fixed it now just trying to get up to max speed, anyone have recommendations for an idle screw i lost mine, still runs fast just cant idle

 

[Oldbiscuit]

If you can’t find an idle screw, try adjusting the knurled end on the throttle cable. Lengthening the cable housing will raise the idle speed.

 

[johngreen]

i think i found one online but its out of stock

 

[Greg58]

That carb is about $12 on Amazon.