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Firing order of a 1981 yamaha xs1100 special? |
My husband just bought a 1981 xs 1100.He has worked on birt bikes but never street bikes. We are hoping to find soeone who can help. If you know the firing order, plz share. greatly appr. It will start but will not idle. When he revs it up, it back-fires like crazy. Any ideas? Thanks n advance for any help you have to offer. Firing Order is 1-3-4-2 ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,... The Cylinders are numbered from Left to Right,as viewed while sitting on the bike ----Front Wheel---- ---(1)-(2)-(3)-(4)-- ----Rear Wheel--- ................................. The Ignition Coils/SparkPlug Coils There are only 2 Coils,,,each with a PAIR of spark plug wires. They are "Dual Fire",,,,each coil fires a Pair of Plugs Simultaneously. Cylinders #1 and #4 are a pair,, and ,,, # 2 and #3 are a pair. The coil mounted on Left side of bike is for #1 & #4,, It will have a LONG spark plug wire and a Short One,,,,obviously due to accomodate the physical Distance across the bike to the #4 Plug The Right hand coil is for #2 & 3 ................................. ELECTRICALLY,,,,there's no difference between each wire of an Individual Coil. Because each coil fires BOTH of It's wires/Sparks Plugs simultaneously. Hope I'm not Confusing the matter while trying to clarify,,,lol Example>>> Right Hand Coil is for # 2 and #3 Cylinder. It's Plug Wires MUST go to #2 and #3. But it does NOT matter WHICH of those 2 wires go to which of those 2 Cylinders. So in a sense,,,"there is no firing order" of an INDIVIDUAL COIL/Plug Wire As Long as the 1-4 Coil is Connected to the 1-4 Spark Plugs,,, and 2-3 Coil is connected to 2-3 Spark Plugs. ................................. XS's have issues with their CDI box,,,dont be surprised to find y'all's being faulty. ANY carbs the age of your XS's can stand a thorough & proper cleaning. Carefully inspect the Vacuum Diaphragms on the CarbSlides. They also have "wiring" and connector issues which have appeared with age,,,in ignition system wiring. Corrosion,etc. I very strongly suggest getting a Factory Service Manual Here are some links to some websites you may find useful. http://www.xs11.com/tips/norm/mctips.htm... http://www.xs11.com/index.shtml... Yamaha Parts Cataloque--parts diagrams,etc http://www.yamaha-motor.com/sport/parts/... ................................. ****Take what ever you read on the net with a grain of salt,,until you can verify the info via cross-refference,etc. Firing Order for example,,To my knowledge Yamaha doesnt publish it. It's POSSIBLE to find it Mis-Stated on the Net. You can VERIFY for yourself that 1--3-4-2 Is Correct by viewing Yamaha Parts pic of the Camshaft & further verify THAT by viewing the Crankshaft. As well as Cylinder Pairing of the Ignition Coils. It's a Paired 360* Crankshaft setup,,,with each pair 180* out. Meaning #1 and #4 Go Up & Down Together. Both are at Top Dead Center simultaneously. So,,One is on Compression while Other is on Exhaust. Therefore,,,their IGNITION SPARK MUST be PAIRED. 1&4 Spark Plugs Share a common coil. #2 & 3 are OPPOSITE,,,they are Both at BOTTOM of their stroke when 1&4 are at Top. Hence,,180* Out of phase versus the 1&4 Pair #1UP #2Down #3Down #4Up Then looking at Camshaft,,,,Note the Lobe Sequence and relationship between them. Cam Turns "CounterClockwise" viewed in Yam Parts Diagram,,,,and when viewed from Left side of bike while sitting. If #1 Lobe is Straight Up,,, as the cam rotates the Next in line to be Straight Up is #3. Then #4,, then #2,,,,and back 'round to #1 again Firing Order is therefore necessarily 1-3-4-2 Keep in mind that as far as Spark Plug Wiring goes,, 1&4 are Paired,,,and 2&3 are paired. You can "criss-cross" Each Pair itself,,,Electrically that works fine--they are the same. 1&4,,4&1,,,no difference.('cept physical wire length:) But Ya cannot Cross-wire the 2 Pairs with each other XS's have their quirks,,same as all else. But really nice bikes once sorted out and going well. They can be a hassle to "restore" in some ways,,,but it's a worthwhile project. Good Luck with it that does not necessary mean that the order is out make sure that the air filters are on right also. One of the biggest problems that is made is people think that before they put on all the accessories they want to hear it run first but, Don't realise that the carbs are vary sensitive to airflow and the filters must be on before the start. If so 1,4,2,3 or 1,3,2,4 It will have to be one of these listed. Also a bad wire may cause this as well or an air leek after the carbs at the manifold. A mechanical problem may also cause this as well. If the popping sound comes out the exhaust ? a bad exhaust valve. If out the intake then an intake valve. A compression test will direct or detect this problem. You should then have the pros look it over. Most older bikes are best to be sold as it is way to much for the repairs then the bike is worth. Cycle Mech badge #a8757 Backfires are one thing and one thing only. Lots of things can cause them, but they are always the result of the same condition. That is fuel/air mixture is combusting in the intake process, instead of the combustion chamber. These are such a kool bike man. I'm nutty for 'em. But check it out. You sound like you could use a thorough carb cleaning and balancing. Start there. Word to the wise, that bike has vacuum timing advance like a car. Very kool stuff there. But it is a bit prone to sticking in its most advanced state. Always a good idea to remove the vacuum line from the carb and suck on it very gently. But I wanted to warn you about the transmissions on those guys. Two of your forward gear ratios are produced via a face to face mating of 3rd and 5th. As you would expect this is achieved by a bunch of pegs with a corresponding hole on the other gear. These pegs are called, "dogs", and the holes are called, "receivers". The dogs themselves are tapered so that shifting is smooth. This taper creates a situation where, under load, the two involved gears will try forcing themselves apart. This is a common issue with unit transmissions. As such, there is a heavy coil spring holding these fellas together while they are mated. The shaft drive is very unforgiving here, and the first time you stomp on it, you'll pop it in and out of gear, which feels like the clutch is sticking. The bike jerks and lurches while applying heavy throttle. This produces excessive wear on the tapered dog. Tapering it even more. Which makes it easier to pop out of gear, and so on until you lose 2nd gear all together. Prior to going to market, Yamaha tried to address this issue with a stronger spring. Didn't help much. Furthermore, once this started happening many owners tried to force the bike to stay in gear by holding the shift lever up or down, as necessary, and wind up bending the shift fork the first time it tries to pop out of gear again. Now the bent shift fork won't quite mate the dog/receiver set up anymore, and the problem gets worse and worse. These shift forks are next to impossible to find, and you will likely have it fabricated if you can't find one. Plus, the fix for this problem is to back cut the dog receiver relationship so that it works like a dove tail joint; and actually pulls the two involved gears together, rather than apart. This, "fix", produces very crappy shifting behavior from then on. It is a ***** to get it into first. And once you are moving, going into and out of 3 rd gets chunky. I end up with 'em stuck in gear a lot, and have to go in through the inspection plate and knock them loose; which requires an engine removal. Plus, this fix requires that you split the cases, which is about a $2500 job at a shop. I'm bringing all of this up, because you should verify that you have a bike with a solid tranny. Does it jump and lurch under heavy acceleration in any gear? It is a hard fix, I'm just saying. If you don't have a solid tranny with which to start, you might consider finding one with a better tranny. Which is exactly what I'd do prior to pouring a bunch of time into getting it running real well. |
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