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Cy Welch

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About Cy Welch

  • Birthday 11/24/1957

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  • Current Bike(s)
    1980 Yamaha XS400G 1980 Yamaha XS1100G

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  • Gender
  • Location
    Sacramento, CA, USA
  • Interests
    Computers, Riding

Cy Welch's Achievements


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  1. I have. They fall in love with them.
  2. 80 and later are electronic ignition.
  3. Good luck, I've been looking for those for a while if they are the ones I think they are. I believe that the same ones are used on the XS1100 for the handlebar bolts too, and I've not found anyplace I can actually get them.
  4. Cy Welch


    No, the XJR is chain drive, the XS 750, 850 and 1100's are shaft drive. And while there are some strange handling characteristics with the shafties, you can learn to handle them just fine once you know how they will react in a given situation.
  5. This does seem to be making things overly complex. When removing an airbox (and LOTS of us XS1100 guys have done that) and switching to pod filters, the new system flows more air. As this causes the carb to work differently it changes the fuel/air mix. Just adjust the jet sizes up to provide more fuel, which is a trial and error type of thing and check the plugs after a full throttle run (clean new plugs) and check the color. If their too white, then you need bigger main jets, if to dark, then smaller. Repeat until you get the right color on the plugs and good performance across throttle settings without flat spots. I'm sure someone out there has changed out the intake on one of those engines and has some idea of how much of a change in jets is needed, but if not, I'd start by going up two jet sizes and see how it runs. Gotta put a load on it to test it though, and you will probably have to go up on the idle jet size too, unless you can compensate with the mix adjustment screw. Trying to get a specific amount of restriction is easy as everyone has said, just create a box or something over the filter and make a hole, and make it bigger till it right (if you don't want to rejet). A good starting point would be to try a hole the same size as the inlet on the stock airbox for the engine, that is likely what's causing most of the restriction with the stock setup. Just remember, you can't tune the carbs (other than idle) out of the frame/bike, cause to tell what it's doing requires a load.
  6. Howdy ecrzeric, I've been to sunshiny florida, and live in sunshiny california. Lived in a few rainy places though, including 5 years in germany (3 as an air force brat and 2 in the army) and some time in even worse places (lots and lots of deep snow (you can ride in the rain, but 3 feet of snow is pretty much not happening)) but never made it to england even given how close I was. I'm still riding pretty much every day, and not gotten more than slightly damp yet, even with no rain gear (just to bug those not riding during the winter).
  7. At least on the American model for 80 the float height is 27.5mm and the floats are supposed to be brass. There is also supposed to be a plug over the idle jets as they pull fuel through the main jets. If it has the stock carbs, they will be Mikuni BS34 III's, which in the U.S. were shared by many other models in 1980, just with different jets and diaphragm springs. The DOHC bikes have a different bowl on them and your supposed to use the clear tube. AFAIK, there is no spec for the 80 carbs outlining the fuel level using the tubes, only the float height setting. Also, a common problem on these carbs is for the o-ring on the push in needle valve seat to wear out and let fuel leak around them causing the carbs to overflow, if that was not replaced you might want to do that.
  8. Ok, here is the deal, your readings are all in the same range I have found on working charging systems. What I have found, is all these years later, the resistance tends to be just a little off from spec, but this is not saying they are bad, just old. The most common failure is the voltage reg or the rectifier (or combined unit depending on what you have). These can be had off ebay used and good pretty cheaply. Oh, and on the newer models contrary to what the haynes (or clymer for that matter) manual, there is no adjustment on the voltage reg, its solid state and non-adjustable. One test is if you check the wiring diagram, there are two wires to the field coil, one get battery voltage and the other goes to the reg and gets partially to fully grounded to energize the alternator. If you have the bike running and ground the side that goes to the reg you should get an increase in voltage at the battery, if not, then the rectifier may be bad, if the voltage does go up the reg is bad. There is also a test in the manual for the rectifier grid that is pretty simple to do and can rule that out as being bad. What I'm saying here is that your readings on the stator wires and field coil are almost exactly what mine read, and mine works great. When mine wasn't working it was the regulator, quick fix (tough to change though being on the bottom of the battery box.
  9. That must cause a bit of a headache! I've managed to get that type out by myself, but I was about ready to throw things before I got it done.
  10. You can use plastidip to fix the diaphragm and it will work pretty well. Otherwise while they are expensive, replacement carbs are going to have old ones too, and once again plastidip may help there.
  11. Any solid core non-resistance plug wire will work. Just make sure it's not that carbon core resistance crap, that won't work, but any solid core wire works with them as long as it fits into the fittings on the coil. Be glad you have the 400, the 1100 don't have replaceable plug wires, you can manage to replace them (usually) but you have to hack the coils to do it. Most install after market coils instead.
  12. Don't matter, even if they fit (which they probably don't) they won't give you any more power.
  13. Cy Welch

    Hard start

    Those air boxes (and related parts) are pretty easy to find on ebay. Otherwise, your carbs NEED to be rejetted, as the cone filters WILL affect the running. Unless the idle mix has been adjust properly also (which I guessing it has not) then it won't idle well (or start for that matter). Also, these are pretty much the same carbs as the XS1100's use, and the mantra on the XS11 site is clean the carbs really good, then clean them again, and then clean them again, meaning it generally takes at least 3 times to get them clean the working well. I know I cleaned mine about 6 times before I got them right. I also had to replace the o-ring under the idle mixture screw spring as those flatten out and go away mostly over the years and these things will NOT idle well without that o-ring. That o-ring is available if you look around, but can be a little hard to find. Also, try spraying wd40 at the ends of the throttle rod and if the idle speed changes that means the butterfly seals are shot, you can get those from MikesXS. It is a LOT of work to get these carbs right, but when they are, it should start easily, I almost never need more than 1/2 choke on mine, and then only for a short time.
  14. Actually that's one of the biggest points of contention about oil in motorcycles. Frankly from most of the research I have seen, the main issues would be with with non-mc oil would be viscosity loss because it's running through the gears, and clutch slippage because of friction modifiers in the oil. My opinion is that oil for use in diesels will protect properly and most of them don't have the friction modifiers so are probably good there. That said, I can buy MC specific oil for just slightly more than normal oil, so I do just because I want my clutch to not slip. Than again I'm not married to using MC oil, and if they want to much more than for the normal oil, I'll just go with the diesel specific stuff, got over 50,000 on my 400 that way with very little wear, and 80,000 on my old engine in the 1100 (although I had to replace it because the PO ran it with gas in the oil and knackered the bearings.) The replacement engine will always have good clean oil changed regularly though, so I expect it to go in excess of 100,000 miles.
  15. Did you get a 2 or 3 prong flasher? A 3 prong flasher will NOT work on these bike, you will need a 2 prong, and just plug it in with 2 of the prongs plugged in, if it doesn't come on at all, then try it the other way. The flashers in these things are SPECIAL and are not ordinary automotive flashers.
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