Question about Yamaha PW 80 Motorcycles

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1986 Yamaha pw80 carb settings

Carb adjustments

Posted by Anonymous on


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Hi, Anonymous you need to make sure you have no intake leaks by spraying some Brake Kleen, Contact Cleaner, Starting Fluid etc. around the intake manifold and seals, if the RPM's go up or down significantly then you have a leak that needs to be fixed before you can continue with the carburetor adjustment.
The engine should be at operating temperature with the enrichener off to set the idle between 950-1050 rpm. Turn the idle skrew clockwise to increase the idle speed and counterclockwise to decrease the idle speed. If you have access to your air fuel mixture skrew you may turn it as well, if not there is a video below on how to gain access, make sure you start with clean or new spark plugs. Gently turn the air fuel mixture skrew clockwise until it starts to bottom out "STOP" do not over tighten as it will damage the taper on the end, now back the skrew out 1-1/2 full turns to establish a starting point start the engine and check the idle rpm's and turn the idle skrew accordingly for 950-1050 rpm if necessary, turn the air fuel mixture skrew 1/4 turn at a time and let the engine settle for about 10 seconds, turn the skrew clockwise for a leaner mixture and counterclockwise for a richer mixture, you are seeking the highest rpm your air fuel mixture skrew can acquire without going past 3 full turns from bottom then resetting the idle skrew back down to 950-1050 rpm If you can not detect any rpm change and can not stall the engine by turning the air-fuel mixture skrew all the way in then your pilot/low-speed jet is too big and needs to be replaced with the next size smaller. Final adjustment should be made with a clean air filter mounted to the carburetor.
For more information about your issue and valuable "FREE" downloads that you will need please click on the blue links below. Good luck and have a wonderful day.
Yamaha Carb Tuning
Life On 2 Wheels
YAMAHA PW80 Owner Service Manual
OEM parts for Yamaha
YAMAHA PW80 Owner Manual

Posted on May 03, 2017


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Posted on Jan 02, 2017

  • 248 Answers

SOURCE: 1986 YF 60 4-Zinger. carb settings

The air/fuel screws won't have any effect on the top end. That would be governed by the main jet. Did you install the Boyseen Reeds? If this is a new addition it could be the problem. Another thing could be the fuel level in the carburetor bowl. When you tore down the carb it is possible the float got out of adjustment. You could drop the bowl and see if the fuel level is correct. If not, bend the tab on the float to adjust it.

Posted on Oct 03, 2009

  • 642 Answers

SOURCE: i have a 1986 yamaha

Refer to the diagram
1 - Overflow drain pipe
2 - Fuel supply(Larger diameter than oil supply line)
3 - Oil supply
4 - Air box
A - Pin for the throttle valve groove. Align the groove in the valve with this pin.
B - Choke valve


Should require further assistance please leave a comment.

Posted on Nov 26, 2010

  • 408 Answers

SOURCE: need to replace crankshaft seals on 1986 pw80 yamaha do i need to split case ?

Not necessarily. You can pull the old ones out with a flat screw driver and install the new ones. Use some lithium grease on the inside surface of the new seals when install them.

Posted on Feb 06, 2012

Testimonial: "hey thamks alot i was hoping i wouldnt have to split that case,"

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