yamagrl Posted April 22, 2016 #26 Posted April 22, 2016 (edited) Be careful! I've read that these things can backfire in your face when running open like that. Keep your head out of the line of fire, so to speak. No you do not need to pull the carbs for these procedures. The diaphragms may or may not need to be replaced. Check them first for pin holes. You can do a temporary fix on pin holes by dobbing a bit of Plasticote or yamabond (5 I think) to plug the pin holes. This'll get ya by for a while. Avoid Hondabond.. it'll make your Yamaha run a lot slower! It sounds like the tiny o-ring (#9) may be missing or damaged or the related passages restricted. The carb has to be able to create a vacuum on the back side of the diaphragm in order to cause oscillation of the slides. Lack of vacuum here can only be caused by 2 things... plugged orifices or air leaking in around that oring or a poor seating of the diaphagm in the carb body/diaphragm cover. The above flow diagram by Prariehammer is an excellent example. http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1984/XVZ12DL/CARBURETOR/parts.html Spray some carb cleaner through them to ensure that they are clear. If the o-ring is nonexistent or damaged you can match it up at a good hardware store. All it has to do is seal that juncture. Make certain that the slide and diaphragm are properly oriented and seated. Some people say that the hole at the bottom of the slide needs to be oriented to the bottom of the slide. I'm not sure about that but I do it anyway, if for no other reason than respect for the Gurus. They said "Do it" so I did it! Here is a link by Skydoc for installing the Sirius diaphrams that I referenced above http://www.venturerider.org/forum/showthread.php?32121-Ebay-Carb-Diaphragm-Replacement! Use a guitar pick (referenced above). https://vimeo.com/163778376 Here is what I saw when I had the air filter off 3 of The slides (I don't know if that is the right word for it) move when I give it gas the 4th (right front carb) slide does not move I can see gas being sprayed when I turn the throttle I can push the slide and it will slide back when I let it go but will not move when I turn the throttle I hope all the above is visible in the video Does that mean I have to pull the carbs to fix or is there a simpler fix Sent from my iPhone using Tapatalk Edited April 22, 2016 by yamagrl
videoarizona Posted April 22, 2016 #27 Posted April 22, 2016 (edited) Thank you @Prairiehammer and @yamagrl !!! Lots of info there @FiDude. Let's hope that helps you with #4 carb.... Edited April 22, 2016 by videoarizona
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