mbowers137 Posted August 13, 2010 Posted August 13, 2010 1980 Yamaha XS 400 Special First, How do you tell if it has an electronic ignition or not? Second, Bike has been setting on a dirt floor building sense 1988. Can't get it to start.Pulled plugs and put some Marvel Mystery oil in top of cylinder head. Used foot start to turn over engine. It was ok. Install new Autolite 63 spark plugs. Change oil and filter, cleaned out fuel tank, install fuel filter. Have put gas in spark plug holes. Didn't hit. Took off the 2 carbs, cleaned and checked..didn't soak it in carb cleaner.The carb rubber mounts are cracked on the outside, but look ok on the inside. Any help in what to do to try and get this engine to try to start and run. Thanks, PS...I'm new to working on motorcycles as you probably can tell.
gmkieran Posted August 16, 2010 Posted August 16, 2010 Welcome to the forum and the joy that is re-building an XS!!! I just finished (mostly) bringing a '79 back to life that had sat the past 15 years. I got nothing until I went back into the carbs for the 6th time and took them *completely* apart. Turns out the idle jet passages (not the jets themselves) and the atomizers in the main jet passage (brass tubes into which the main jet threads - didn't even know there were removable to begin with) were both clogged. If you can, tear the carbs all the way down and soak them. If you can't do that, at least pull them as far down as you can and use pipe cleaners to get to the passages. Don't forget to get the choke passages, while you're in it. make sure that the jets attached to your floats move freely, too. Take a look at the service manuals stickied at the top if this thread, if you don't already have one for your bike; they're invaluable! To the electronic ignition question, not sure if you mean electric start (check for a push-button control on the right-hand bar with a wire running to a cover directly below the carbs) or electronic ignition timing (check the cover on the top left of the cylinder heads - if you can remove it, you have points, not electronic advance ignition). My '79 has both, I would expect your '80 to, also. Rather than putting gas directly into the plug wells, pull the air boxes (leave 'em off, for now) and blow a little starter fluid into the carb air passages (both sides) while holding the throttle open. Then try to kick it. If it tries to fire at all, that indicates that your coils are good, at least. BTW, if the carb rubbers are cracked on the outside, they're probably not going to seal properly (no matter what the inside looks like) and will need to be replaced sooner rather than later. best of luck and have fun!
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