Question about 1972 Yamaha XS2

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Yamaha 1979 GT 80 won't stay running set float cleaned carb new needle and seat bogs at top end

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  • Yamaha Master
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Hi, Anonymous and the usual suspects are:
1. Inlet system air leak.
2. Enrichener valve not seated or leaking.
3. Damaged or restricted fuel tank vent system.
4. Restricted fuel supply tract.
5. Dirty or damaged air cleaner element.
6. Plugged bowl vent or overflow.
7. Worn or damaged needle or needle jet.
8. Vacuum piston assembly malfunction.
9. Loose or plugged main jets or passages.
10. Improper float level.
11. Accelerator pumps inoperative.
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have nice a day.
https://yamahaclub.com/forums/topic/16021-1979-yamaha-gt80-wierd-problem
Yamaha GT 80 Problems
DOWNLOAD NOW Yamaha GT80 DT100 GT 80 DT 100 77 82 Service Repair Workshop...
OEM parts for Yamaha
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Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

Posted on Dec 22, 2016

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Posted on Jan 02, 2017

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heimlich
  • 1978 Answers

SOURCE: Yamaha banshee. Just rebuilt top

Check the plug color to see if it is normal. I would put new spark plug caps and new spark plugs on the machine and see if that helps . From what you describe , if the spark plug caps do not work , you will probably have to either , adjust your air screw setting or change your pilot jets up one size to compensate for the other changes.

Posted on Aug 17, 2010

mxtras
  • 194 Answers

SOURCE: I have 1979 yamaha GT

Running with the choke on is a classic indicator that the pilot circuit in the carb is too lean. Richen your pilot (low speed) circuit (the small jet in the bowl) by replacing it with a larger jet. Keep in mind I am not familiar wih this exact bike but I believe the advise to be solid.

Posted on Sep 10, 2010

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2003 yamaha yfz450 float setting,how to set float on a dirt bike. i would like to know inches


The float hight does not change it is preset at the factory,but if someone messed with it set it parrel with the carb body.While your at it replace the needle and seat ,check the floats for a hole in them,check to make sure the drain on the float bowl is snug.I suspect that you need a new needle and seat.

Sep 15, 2015 | Yamaha Motorcycles

1 Answer

Flooding


A) I didn't know Yamaha makes a Desktop PC.

B) So far, I don't know of any desktop computers that use an internal combustion engine, and use a fossil fuel to run it.
Hope not because this is going against the grand scheme of things, lol!

C) Fresh top end, and a carburetor fuel induction system; plus flooding out?

1) Float level is set too high.
Readjust level. Worked fine before top end job?
Maybe it got bumped.......umm, like dropped.

Carb was rebuilt too? Float level is not correct.

2) The tip of the float needle is Neoprene. As such it can be damaged from a fall.
It can also be deformed from having too much pressure applied to it, when installing.

3) Float needle seat has come loose from carb main body.

4) Float needle seat is damaged. Tightened too tight, etc.

5) Junk in fuel tank has made it's way into between float needle, and float needle seat.

6) Float needle hair spring clip, was not properly installed on float.
(If used)

7) Carb was Not rebuilt, has sat while top end was done. This took some time, like weeks, months, to get too.
All the cr@ppy additives in the gasoline, has collected in the float bowl; and causing float needle to not set correctly in float needle seat.

Regards,
joecoolvette

(Now watch. You'll come back with a voice like Stimpy, and state;

"joecoolvette, you stink-ing idio-t!
I was referring to my Yamaha desktop computer. It's spraying gas out of the carburator. You have no idea of what you're doing.

Signed, Stimpy)

Mar 26, 2013 | Computers & Internet

1 Answer

I have a 2003 yamaha yz 85 . I have doin everything i can think of to try to get it to quit bogging ,I have put a new top end rebuilt carb put a new silencer change the fuel mix to 32.1 36.1 & 40.1...


Hi, Crazycowboy1 and the usual suspects are:
1. Fuel cap or fuel tank is not venting properly.
2. Fuel filter clogged.
3. Fuel line pinched or kinked.
4. Float needle and seat sticking.
5. Float level too low.
6. Carburetor bowl vent line clogged/blocked/pinched.
7. Idle adjusting screw set too low.
8. Air/fuel mixture screw set too lean.
9. Idle port, transfer ports, slow air jet clogged.
10. Slow fuel jet clogged.
11. Faulty fuel pump.
For more information about your issue and valuable "Free" downloads that you will need please Click on the links below. Good luck and have a nice day.
Dirt Rider Magazine
YZ85 cutting out at WOT Yamaha 2 Stroke
YAMAHA YZ85 Owner Manual
OEM parts for Yamaha
YAMAHA YZ85 LC Owner Service Manual

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

Mar 23, 2013 | 2005 Yamaha yZ 85

1 Answer

I have a pw 80 that runs perfect in neutral when you put it in gear it runs fine until you try to go then it bogs out. I put a new cylinder, head,piston and ring as well a new carb. It still does the


Hi, Anonymous and the usual suspects are:
1. Severely drained or faulty battery.
2. Faulty regulator/rectifier or high output coil.
3. Faulty power valve, solenoid or installation.
4. Clogged air filter or exhaust.
5. Cracked or incorrect float level.
6. Float needle is not seating.
7. Faulty reed valve.
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Pw 80 runs awful
PW 80 problems with it bogging out
YAMAHA PW80 Owner Service Manual
OEM parts for Yamaha
YAMAHA PW80 Owner Manual

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e


Dec 01, 2012 | 2005 Yamaha PW 80

1 Answer

Pw50 leaks gas


Hi, Anonymous "ABSOLUTELY" and the usual suspects are:
1. Damaged or restricted fuel tank venting system.
2. Loose float bowl screws.
3. Damaged float bowl o-ring.
4. improper fuel level in the float bowl.
5. Worn or dirty inlet valve or seat.
6. Damaged or leaking float assembly.
7. Particle contamination in inlet fitting cavity.
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.
PW50 carb won stop leaking fuel
Yamaha PW 50 checking carb
https://books.google.com/books?id=ozV8-Aer4N8C&pg=PA84&dq=pw50+manual&hl=en&ei=TCS2TcbdJ4PW0QG0z9jmDw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CGUQ6AEwAA#v=onepage&q=pw50%20manual&f=false
OEM parts for Yamaha
Yamaha PW50Y Owner Manual

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Jun 01, 2012 | 2005 Yamaha PW 50

1 Answer

Runs rich backfires and bogs out during exceleration


Check the float level,,also could be some dirt in the needle and seat,,remove the carb and give it a clean and check float level.

Aug 30, 2011 | Yamaha XJ 650 Motorcycles

1 Answer

This is for an 1979 Honda CBX. I installed new float needles and seats. Also, I adjusted float levels to factory specs. All carbs are still flooding.


I PRESUME YOU THOROUGLY CLEANED THE FLOAT NEEDLE SEAT?AND INSPECTED THE NEEDLES FOR LIKENESS COMPARED TO THE OLD ONES, SOMETIMES YOU HAVE TO IGNORE THE FACTORY SETTINGS PLACE THE CARBS ON THE BENCH WITH A FUEL SUPPLY CONNECTED AND ADDJUST EACH FLOAT UNTILL THE LEVEL OF FUEL IS BELOW THE OVERFLOW TUBE ALLOWING ENOUGH ROOM FOR THE FLOATS SO THAT THE LEVEL STILL LYES BELOW THE TUBE WHEN FULLY ASSEMBLED, COMPLETE THIS TEST BEFORE FIXING THEM TO THE BIKE, WHEN YOU ARE HAPPY REPLACE THEM BACK ON THE BIKE,

PS IS THE NEEDLE SEAT AVAILIBLE SEPERATLY MAYBE WORTH INVESTING INSOME NEW 1S IF THEY DO

YOU COULD HAVE THE CARBS ULTRASONICALY CLEANED

Feb 27, 2011 | 1979 Honda CBX

1 Answer

I have 1979 yamaha GT 80. It starts with the choke on but will not stay running i have cleaned the carb it has a new carb kit in it


Running with the choke on is a classic indicator that the pilot circuit in the carb is too lean. Richen your pilot (low speed) circuit (the small jet in the bowl) by replacing it with a larger jet. Keep in mind I am not familiar wih this exact bike but I believe the advise to be solid.

Sep 10, 2010 | 1972 Yamaha XS2

1 Answer

I have a 2001 pw 80 and i cant get it to idle i cleaned the carb and when i shift into 2nd it bogs and it has very laggy top end


Hi, Racer148 and the usual suspects are:
1. Idle circuit and transfer ports clogged.
2. Air fuel mixture adjustment too lean.
3. Pilot jet clogged.
4. Faulty accelerator pump.
5. Float level too low.
6. Float bowl contaminated old fuel, water, dirt, rust, etc.
7. Float bowl vent or overflow tube clogged.
8. Fuel flow to carburetor restricted.
9. Intake manifold leak.
10. The gas cap is not venting properly or fuel tank venting system blocked.
11. Vacuum line from intake manifold to petcock broken, cracked, or not attached, carburetor vent line plugged.
12. Needle and seat stuck closed in the float bowl.
13. Multi carburetors not in sync
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have nice a day.
Dirt Rider Magazine
PW50 and PW80 carb problems
YAMAHA PW80 Owner Service Manual
OEM parts for Yamaha
YAMAHA PW80 Owner Manual

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

Mar 05, 2010 | 2004 Yamaha PW 80

1 Answer

Gas running from carb when the bike is running or not


Sounds like your float needle is not seating properly, or your float height is incorrect, or you have trash in the carb. It will need to be taken apart, cleaned, and the float height set. Look at the float needle for wear on the tip.

Aug 07, 2009 | 2004 Yamaha YZ 450 F

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