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1979 XS1100 Not a XJ900 but it will do for now

Discussion in 'Other Motorcycles' started by Timbox, May 1, 2019.

  1. JetmechMarty

    JetmechMarty Active Member

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    [​IMG]
    Torozzi rearsets for XS1100 Sport should fit the Special. I have yet to try it. FastFromthePast.com is the Torozzi source. They also have a fork brace and fork tubes. That machine can get an easy makeover without cutting anything up.
     
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  2. Timbox

    Timbox Well-Known Member

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    Now that the BMW is off getting worked on, I got time to work on the XS! I turned the petcocks on to prime them and #3 started to leak. I need to order a rebuild kit for the needle valve, the one that shuts off the fuel when the floats rear their level. I know I am running a too low of main jet with the UNI filter and the 4-1 Kerker pipe. I can't remember how many I need to go up with the main. The stock is 137.5. I am guessing +3 with both the air and exhaust mods? Making it a 140.5

    Okay, 4 rebuild kids with 140's on the way. Hope this does it. I will have to change out the seat and also the bars. Coming along with that will have to be the brake lines, if I change out the bars I am sure the stock stuff will no longer fit correctly.
     
    Last edited: Jun 29, 2019
  3. Timbox

    Timbox Well-Known Member

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    Pulled the carbs today, I don't mind pulling them on this bike, lots of room when the air box is pulled back. The needles jets seem to be okay, but no way are the old ones going back in. Once the new kit gets here new main 140's and the new needle jets go in.

    The plug boots had tape on them, pulled the tape off and found out why. The #4 was broken so bad that the tape was holding it together. The #1 was close to the same, 2-3 were good. So new boots and I would guess some new plugs are in order too.

    Painted the header too, will see how that stays on with heat. Need to do more painting of the rear hub too.
     
  4. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    What paint did you use?
    Did you scuff up what little chrome was left on them?
     
  5. Timbox

    Timbox Well-Known Member

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    k-moe, you are right to ask me about the paint, I suck at it....lol. I used an exhaust paint from the auto store just for exhaust. I went with a ceramic mixed paint. I did sand them down and clan them off the bike. Once I got them on the bike, they didn't look good in the aluminum color, so I hit them with semi-gloss black hi temp after that. We will see how long that lasts. The pipes were well rusted to the point of little pitting. They are in over all good shape.
     
  6. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    As long as you did some prep work the paint will hold up for several years. It might even be there arfter the pipes have rusted away.

    Based on your concerns, I was concerned that you might have used ordinary enamel.
     
  7. Timbox

    Timbox Well-Known Member

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    It has always been a issue with me, painting that is. I would love to sand down this tank and get rid of all the little blems in the tank and some of the surface rust that will eventually turn into a issue. I just think when I try to paint it is either too humid or it is just me. I never seem to get the paint the way I want it and it seems to come out foggy looking.

    I have not tried that clear coat that holds up against gas yet, that could be the ticket. That and making sure I wait long enough to let the paint dry. I do think this tank needs to be done and the BMW I am working on should be done too.
     
  8. Timbox

    Timbox Well-Known Member

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    Got me stampeded! I put the 140 mains in and also re-ran the fuel lines so I know they are not hindering the fuel low. I start the bike, runs great, comes off of choke in a very short time and runs well. Then take it on the road and give it a twist and it is almost like there is a governor on it at 5k! As stated above, I took the carbs to church, normally it would be a low rmp issue or idle issue, not the case.

    Are my secondary jets not even kicking in? If so why not? The new larger jets, the very clean emulsion tubes, just a head scratch-er for me. Hit he pips with a IR temp guage and all the exhause pipes were very close. Nothing cool so all are firing and running.

    It just dawned on me, ignition advance? I think these bikes had issues with one of the wires breaking or cracking...I am guessing that would make it top out in the RMP range?

    Any advice would be great...anyone think it might be the advancer?
     
  9. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    That fits. I once had a problem with my old truck that I thought was a plugged-up fuel filter (that problem had occured several years before, so naturally I went straight back there). She would bog down at 3,000 RPM (smallblock V8). Turned out to be a hidden crack in the vacuum line to the advance diaphram.
     
  10. Timbox

    Timbox Well-Known Member

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    I think it is the vacuum advance but now to play around to what port to run the vacuum to? I currently have it hooked to #2 carb as I think that it how it was from factory. I removed the Oct fuel thing and have plugged that vacuum port, I think I will try to change the advance over to that nipple and see if it works better.
    [​IMG]DSCN0323 by Tim Brown, on Flickr
    [​IMG]DSCN0329 by Tim Brown, on Flickr
     
    Last edited: Jul 8, 2019
  11. FJ111200

    FJ111200 Active Member

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    That's right mate. The take-off spigot on number 2 carb, NOT the carb to head manifold.
    If you have it connected to the carb to head manifold the vac advance will just rattle and jump around like a good 'un.
     
  12. Chitwood

    Chitwood Well-Known Member

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    May not hurt to make sure the mechanism itself moves freely and isnt sticky causing inconsistent timing. Making sure the line is hooked to the proper location would definitely be my first go to though also
     
  13. Timbox

    Timbox Well-Known Member

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    Thanks for the response, I made sure the hose was good and watched the timing advance with vacuum applied. I cleaned the timing wheel and lubricated it with PB blaster on a "Q" tip, I didn't want to over do it.

    I am stepping away to try to think this through. Can't be anything else has to be the timing issue. Working on another bike for a while so I can come back to this and maybe have a fresh set of eyes to make it work. I sure love the power this bike has when you roll on the throttle, just wish it didn't stop at 5KRPM.
     
  14. Timbox

    Timbox Well-Known Member

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    It has been a while sense I had room for the old XS in the shop. I got to her today! I found the issue with the 5K issues, how about a kinked fuel line on both side! I can't beleive I missed that when I was trying to rout the fuel line. So, new fuel line is on and I am getting some alternate petcocks and we will try this again.

    I did set the timing, it was a little off, closer to the "T" mark than to the "F" mark.
     
    JetmechMarty likes this.
  15. Timbox

    Timbox Well-Known Member

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    New fuel line with filters are in, looks much better under the tank. The issue is still there for the 5k RPM issues. I will take a look at all the wires going to the ignition pickup tomorrow. I only looked at one of the wires that was broken, I will check the rest now. That is the only thing I can think of that is still holding this bike back from yanking my arms off. This is a common problem with this bike as the wire are so small and the vacuum advance makes the wires mover all the time. Bigger wires and make sure they are all connected well and I hope that will fix it.

    This will be more helpful to show what I need to do.
    http://www.xs11.com/forum/showthread.php?t=543
     
    Last edited: Aug 18, 2019
  16. Timbox

    Timbox Well-Known Member

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    Well, now it has to be the vacuum control system. I tested and replaced the ends of all four of the pickup wires. Tested them back to the connector behind the fuse box holder. So they only thing left is the vacuum control. Not looking forward to finding one of those for this bike. I don't want to spend the $$ for the alternative, the electronic version for $300 plus.
     
  17. JetmechMarty

    JetmechMarty Active Member

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    Check Partzilla or your favorite OEM parts source. The vacuum pot may still be available.
     
  18. Timbox

    Timbox Well-Known Member

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    Gremlins are still winning this long term fight. I got a chance today to take apart the vacuum and mech timing advance. This is the mech that looks good but I took it off and cleaned it and put a little Mystery oil on the springs and pivot points before she went back in place.
    [​IMG]Mech advance by Tim Brown, on Flickr
    The pickups were also cleaned and new connectors were installed with larger wires.
    [​IMG]Pickups by Tim Brown, on Flickr
    [​IMG]connectors by Tim Brown, on Flickr
    [​IMG]New crimps by Tim Brown, on Flickr
    The timing plate never moves when you removed the advance. The bike tired right up and sounds good, but the 5K threshold is still there. So I have two options.
    1. I will be pulling the carbs again to see what could be wrong? I measured the temps of the pips and they are all very close to being the same (IR) temp gauge.
    2. The CDI or brain box could be done.

    I will have to do some more reading to find out why this bike would have two ways for it to get it's timing advance. Vacuum and Mech force both are on this bike. This thing pulls like a bears from 1.5K to 4.5K or so RPM and then it is done in all gears.
     
  19. JetmechMarty

    JetmechMarty Active Member

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    You get mechanical advance when you crack the throttle and RPM climbs. The vacuum advance will operate at cruise. The vacuum advance should improve fuel economy.

    Make sure your new wires don't restrict movement of the mechanical advance.

    By today's standards the XS1100 is a turd, but in its day it was a powerhouse and briefly, king of the hill. It's still great fun to twist the throttle and it is a bargain as compared to a GS1000 or KZ1000. Once sorted, it's a reliable rocket.
     
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  20. Timbox

    Timbox Well-Known Member

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    I made sure that I have plenty of room and that the wires are secured and won't get cut or rubbed on by the moving parts in that area. Went through the carbs again to make sure the right carbs for the right bike, check. Right jets in those carbs, again check. Are the diaphragms are good as new...no but they are working and holding when hole is plugged up front.

    So the mech advance is working just great when it come to the bike sitting and just flicking the throttle. That is why I was wondering why when in gear the bike hits that 5K wall. All things are still pointing to the carbs. It could be I missed something. I will give it a day and come back to it.

    Here is the TDI and it looks like it might have have been worked on before? Those connector pins joints look like they need a little heat applied to them? If the TDI was bad, the bike would not run through the full range of RPM's when sitting. So the box should be good.
    [​IMG]20190829_081953 by Tim Brown, on Flickr
     

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