1980 yz 80 won't stay running

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 10, 2007

• #1

can anyone tell me what to do. its my first dritbike and i have no clue where to start.

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Jun 10, 2007

• #2

Clean the carb and make sure the float is operating properly. What are the exact sypmtoms of your problem?

 

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 10, 2007

• Thread starter
• #3

what is the float? it will start fine and everything but then i will like take it for a little rip and i'll come to a stop and it'll just die.

 

S

sixds

Member

Mar 25, 2007

779

0

• Jun 11, 2007

• #4

i had a problem with an old bike of mine. let it warm up thoroughly for about 3-5 minutes then go. is it fouling a plug?

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Jun 11, 2007

• #5

You take it for a little rip and it dies when you come to a stop? As in the bike doesn't idle? Does it start right up after it stops?


The float maintains the fuel level in the carburetor. If for some reason it's not opening all of the way (stuck or out of adjustment), the fuel level could drop slowly as you ride the bike and the bike may eventually die (run out of gas). The bike would be a little hard to start for a while after it died, until the bowl filled again.

 

T

tylerelias

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Jun 10, 2007

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0

• Jun 11, 2007

• Thread starter
• #6

yea it will start right up again. and how do i tell if its fouling a plug?

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Jun 11, 2007

• #7

It's not fouling the plug if it starts right up again. It sounds like it's just not idling. If you keep revving it when you come to a stop does it still die?

 

T

tylerelias

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Jun 10, 2007

16

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• Jun 11, 2007

• Thread starter
• #8

if i keep revving it, it will stay running.

 

IndyMX

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Jul 18, 2006

5,548

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Amo, IN

• Jun 11, 2007

• #9

2 Stokes aren't supposed to idle forever.. mine will die pretty quick, that's how I like it..

 

Patman

Pantless Wonder

LIFETIME SPONSOR

Dec 26, 1999

19,765

1

• Jun 11, 2007

• #10

Picup a service manual for your bike, it will help A LOT in understanding what the pieces are and basic trouble shooting & maintenance.

 

T

tylerelias

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Jun 10, 2007

16

0

• Jun 11, 2007

• Thread starter
• #11

well i took off the carb and opened er up and it looks clean. and the float isn't stuck or anything. so i'll put it back on and i'm gettin a new plug and air filter as well so i guess we'll see how it goes.

 

IndyMX

Crash Test Dummy

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Jul 18, 2006

5,548

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Amo, IN

• Jun 11, 2007

• #12

tylerelias said:

well i took off the carb and opened er up and it looks clean. and the float isn't stuck or anything. so i'll put it back on and i'm gettin a new plug and air filter as well so i guess we'll see how it goes.

Click to expand...

Looks? don't go by that, clean it..

 

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 13, 2007

• Thread starter
• #13

alright well what should i clean it with?

 

F

FULL-ON

Member

Jun 3, 2007

6

0

• Jun 13, 2007

• #14

carb cleaner

 

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 13, 2007

• Thread starter
• #15

i never knew there was such a thing lol.

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Jun 13, 2007

• #16

From what I gather, everything is working normally. You're just not used to the short idle period of a 2-stroke. You can adjust some things on the carburetor to make the bike idle for longer, but the best throttle respons and best resistance to fouling plugs is with the carb set to idle for only a second or two after you let off the gas.

 

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 13, 2007

• Thread starter
• #17

well i got it goin and it will idle. but it will idle sky high. whats the problem?

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Jun 13, 2007

• #18

If the black choke knob is adjustable, use that to bring it down (clockwise). Otherwise, there will be a screw near the center of the carb on the side (counter clockwise). That could be it. You might need to make some adjustments on the pilot screw to restore the throttle response, near the seperation of the float bowl/carb main body on the airbox side. 1 1/2 turns is a good start, if you can't get it right with plus or minus a turn, you'll have to change the pilot jet. For the pilot screw, counterclockwise is leaner, clockwise is richer. I don't know exactly what carb is on the bike, so things may be different, but this covers most carbs on 2-strokes.

If nothing you do controls the idle or the bike is slow to return to idle after a rev, the pilot jet may be too lean or there is an air leak.

 

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 13, 2007

• Thread starter
• #19

k well now all of a sudden it won't start anymore? whats up with that?

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Jun 13, 2007

• #20

All that idling may have fouled the plug.

What is your startup procedure? On a 2-stroke, if the choke is off, you've got to roll on the gas a little as you kick it.

 

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 13, 2007

• Thread starter
• #21

yea thats how i start it.

what kind of spark plug should i use for my bike? its an 81, i just figured that out when i went to get a new air filter and the 81 needs a cylinder type.

 

7

76GMC1500

Uhhh...

Oct 19, 2006

2,142

1

• Jun 13, 2007

• #22

On a bike that old, make sure you inspect the reeds. If they are worn, that could make it hard to start.

 

T

tylerelias

Member

Jun 10, 2007

16

0

• Jun 14, 2007

• Thread starter
• #23

and what are the reeds.

 

IndyMX

Crash Test Dummy

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Jul 18, 2006

5,548

2

Amo, IN

• Jun 14, 2007

• #24

Reeds are what prevent pressure from the crank case from backing up into the carb.

They are in the block between the carb and crank case.