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Back in the fold: '79 XS1100F

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  • Back in the fold: '79 XS1100F

    After a bit of a bikeless hiatus where I sold all the bikes in a fit of downsizing and life simplification (and frustration at still not quite getting my green '78E fueling sorted out fully after many many rounds of diagnostics and jetting combinations etc with the '80 carbs; I think it was down to how I had the RC pipe baffled excessively, that or worn needles/emulsion tubes), I just couldn't stay away from the "Elevens." I considered buying something newer with fuel injection, I considered dipping my feet back into (single carb) Harley ownership, but at the end of the day I just think these XS1100s are absolutely fantastic machines, and the perfect combination of classic looks, awesome usable real world power, and comfort/touring ability.

    Part of my motivation being okay with selling the '78 E was knowing that my buddy had a really clean single owner '79 F that I helped him purchase back in 2022 that he would be willing to sell to me if/when I was interested. Unlike my old '78 that had had a few too many "cooks in the kitchen," this '79 is unfettled with, the original owner bought it new in '79, and sold it to me/my buddy in 2022. The only changes from stock are the 4-1 Kerker pipe (previous owner said he installed it after the stock exhaust rotted out the mufflers), and a luggage rack/sissy bar combo. From what I recall having briefly ridden it, it must be rejetted, I recall it needing minimal warmup.

    On the to-do list is a thorough general going through of the machine, it has the usual symptoms of pickup coils breaking internally, though the one time I took a look at it while visiting my buddy, I could not find an obvious fault with them. The bike needs new tires, I'll install galfer braided front brake lines and take a look at the condition of the braking system in general, double check that the stock vacuum petcocks aren't leaking, take a close look at the carb intake boots (I know they look pretty nasty and cracked externally... are the K&L replacements any good?).

    I forget, but I think the '79 Fs still ran tube tires, and I forget whether this one had already been swapped to the tubeless style rims or not by the previous owner, but if not that will certainly be on the list of to-dos (I may just plug off the rim locks with brass NPT fittings and only swap the easier-to-source front rim).

    But the idea is to simply preserve and enjoy this nice, stock, unmolested bike with a few functional upgrades mentioned above. I really want to do some touring on it, so the luggage rack and possibly a small windshield will likely find their way onto the bike at some point when the time comes.

    Part of the motivation to come back to the XS11 was also this awesome and very helpful community!

    Click image for larger version

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    Yamahas: 1979 XS1100F
    Past Yamahas: 1978 XS1100E, 1976 XS500C

  • #2
    Nice bike. Still has the old style seat which is great. Airbox, Mac pipe & center stand still attached. If your rear rim has mag locks you have a set of tube rims.

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    • #3
      Originally posted by DEEBS11 View Post
      Nice bike. Still has the old style seat which is great. Airbox, Mac pipe & center stand still attached. If your rear rim has mag locks you have a set of tube rims.
      Thankfully it's a Kerker, I haven't had the best luck with Mac brand exhausts.
      Yamahas: 1979 XS1100F
      Past Yamahas: 1978 XS1100E, 1976 XS500C

      Comment


      • #4
        What an amazing picture. I am the original owner of the exact same bike. I painted it black after only a couple years or so of ownership. I forgot exactly how it looked.

        The bike is now running with a Kirker exhaust and a Vetter fairing. Much better when traveling across multiple states at the old highway speed limits. I still have all of the original parts and this picture has I believe motivated me to get it back to STOCK except with the Kerker.

        I have played around with the carbs so many times, but I believe I now have a good setup that works well with the Kirker, stock air box and a single K&N air filter if you are interested. I also just went thru the painful experience of replacing the Fuel Line Tee's connected to the Carbs. They were leaking badly. All new fuel and Vacum hoses.

        Yes the tires do have tubes.

        I replaced the rubber carb boots years ago, they were badly cracked.

        The front brake calipers have been replace. Pistons rusted. Rebuilt the front brake master cylinder.

        I did SS brake hoses years ago, what a difference with brake feel.

        Replaced the front fork head bearings at about 30 years old. Plus new fork seals.

        I did the mod on the coils where you remove a bit of both ends of the plug wires for better connection

        Replace the Fuse "Box" with a replacement that look very similar to the original but required me to splice into the wiring harness since did not have the same connector at the end of its wires.

        Years ago I had to "repair" the flasher solenoid. It was an easy fix.

        Have never needed to break open the engine but have adjusted the valves many times. They seem to have "seated" though since no changed for some time now.

        Mikes XS has been a good resource for parts.
        Jeff Korn
        Original Owner 79XS1100 E
        Yamaha Warrior has come and gone

        Comment


        • #5
          Originally posted by jkorn View Post
          What an amazing picture. I am the original owner of the exact same bike. I painted it black after only a couple years or so of ownership. I forgot exactly how it looked.

          The bike is now running with a Kirker exhaust and a Vetter fairing. Much better when traveling across multiple states at the old highway speed limits. I still have all of the original parts and this picture has I believe motivated me to get it back to STOCK except with the Kerker.

          I have played around with the carbs so many times, but I believe I now have a good setup that works well with the Kirker, stock air box and a single K&N air filter if you are interested. I also just went thru the painful experience of replacing the Fuel Line Tee's connected to the Carbs. They were leaking badly. All new fuel and Vacum hoses.

          Yes the tires do have tubes.

          I replaced the rubber carb boots years ago, they were badly cracked.

          The front brake calipers have been replace. Pistons rusted. Rebuilt the front brake master cylinder.

          I did SS brake hoses years ago, what a difference with brake feel.

          Replaced the front fork head bearings at about 30 years old. Plus new fork seals.

          I did the mod on the coils where you remove a bit of both ends of the plug wires for better connection

          Replace the Fuse "Box" with a replacement that look very similar to the original but required me to splice into the wiring harness since did not have the same connector at the end of its wires.

          Years ago I had to "repair" the flasher solenoid. It was an easy fix.

          Have never needed to break open the engine but have adjusted the valves many times. They seem to have "seated" though since no changed for some time now.

          Mikes XS has been a good resource for parts.

          Jeff if you have a stock exhaust in good shape, would you be interested in selling it perhaps?
          Yamahas: 1979 XS1100F
          Past Yamahas: 1978 XS1100E, 1976 XS500C

          Comment


          • #6
            Originally posted by gtem View Post

            Thankfully it's a Kerker, I haven't had the best luck with Mac brand exhausts.
            Are you sure about that? This is a Mac and it looks very similar to your pipe.

            https://www.ebay.com/itm/305799566075


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            • #7
              EDIT: right you are Deebs, in my memory I was absolutely certain I saw a Kerker sticker on the back of the pipe when I had it in my possession for a few weeks two years ago, but looking through the few photos I took I can find no evidence of such. It indeed seems to be a Mac! My apologies.
              Last edited by gtem; 10-17-2024, 05:07 AM.
              Yamahas: 1979 XS1100F
              Past Yamahas: 1978 XS1100E, 1976 XS500C

              Comment


              • #8
                I was looking at the excellent writeup in the interchange guide in regard to differences in ignition advance between the model years. Would switching back to the more aggressive '78 E base timing and curve be as simple as sourcing the springs and slotted bits and swapping them over to the '79? TCI, cams, identical? This is all purely hypothetical, the priority is to first get the bike 100% sorted and in good riding condition and putting some miles down before any of this sort of thing.
                Yamahas: 1979 XS1100F
                Past Yamahas: 1978 XS1100E, 1976 XS500C

                Comment


                • #9
                  Originally posted by gtem View Post
                  I was looking at the excellent writeup in the interchange guide in regard to differences in ignition advance between the model years. Would switching back to the more aggressive '78 E base timing and curve be as simple as sourcing the springs and slotted bits and swapping them over to the '79? TCI, cams, identical? This is all purely hypothetical, the priority is to first get the bike 100% sorted and in good riding condition and putting some miles down before any of this sort of thing.
                  One way to see if parts are identical between model years would be to go to the parts fische and compare them, the Partzilla site makes this easy since they list all the models and years a particularly part is fitted on.
                  1980 XS1100G

                  I identify as a man but according to the label on a package of Stauffers Baked Lasagne I'm actually a family of four!

                  Comment


                  • #10
                    I know the TCI is the same for '78/'79, but I think the '78 had a little different cams. I'm not positive on the advance durve, but I don't think that changed much until '80.
                    Ray Matteis
                    KE6NHG
                    XS1100 E '78 (winter project)
                    XS1100 SF Bob Jones worked on it!

                    Comment


                    • #11
                      Originally posted by DiverRay View Post
                      I know the TCI is the same for '78/'79, but I think the '78 had a little different cams. I'm not positive on the advance durve, but I don't think that changed much until '80.
                      This was the page I referenced for the mechanical advance changes put together by crazy steve back in 2011:

                      https://xs11.club/forum/repairs/inte...nical-advances

                      "The 78 unit offers 26 degrees of advance, starting at 2150 rpm and it's all in at 4750 rpm, for a 'range' of 2600 rpm. The slots in the reluctor are .515"/.530" long; this is what determines total advance. The springs have 13 coils, and a wire diameter of .033". Remember that the 78 uses 10 degrees of initial timing for a total of 36 degrees @ 4750 rpm.

                      The 79 unit has 31 degrees, starting at 1800 rpm and it's all in at 5400 rpm, for a range of 3600 rpm. The slots in the reluctor are .565"/.585", and the springs have 15 coils with the same wire diameter as the 78 bits. Initial timing is retarded to 5 degrees, but you have the same total of 36 degrees, although at a higher rpm (5400).

                      The 80 unit also has 31 degrees (OK, the manual says 30), also starting at 1800 rpm but this is all in by 3900 rpm, for a 2100 rpm range. The slots on the reluctor are the same as the 79 unit, but the springs are lighter; 14 coils with a wire diameter of .028". Again, the same initial 5 degrees and total timing of 36 degrees, but all in at only 3900 rpm."

                      So the '78 had 10 degrees initial timing advance vs 5 degrees on the '79 and '80 components.

                      Does all of this even matter that much, especially compared to just making sure that the fueling is sorted out on a 45+ year old bike? I suppose not. But I guess I have a bit of a mental hangup knowing my previous bike was the "fast" one and that this incoming '79 had been "detuned."
                      Yamahas: 1979 XS1100F
                      Past Yamahas: 1978 XS1100E, 1976 XS500C

                      Comment


                      • #12
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                        • #13
                          I prefer the stump pulling low and midrange power of the 1980 timing parts coupled with the 1980 cams. A peaky, high rpm motor is not fun to drive unless you are constantly ripping on it. I guess it's fun if you like doing that. Poor motor.

                          Comment


                          • #14
                            Originally posted by DEEBS11 View Post
                            I prefer the stump pulling low and midrange power of the 1980 timing parts coupled with the 1980 cams. A peaky, high rpm motor is not fun to drive unless you are constantly ripping on it. I guess it's fun if you like doing that. Poor motor.
                            I'd be inclined to agree on prioritizing the "usable" part of the rev range over bragging rights. Do you run the '80 cams in an 80-81 motor with the bigger valves or a hybrid combo of high compression smaller valve 78/79 motor with '80 cams?
                            Yamahas: 1979 XS1100F
                            Past Yamahas: 1978 XS1100E, 1976 XS500C

                            Comment


                            • #15
                              I run a stock 1980 motor out of this bike.

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