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  • Cam timing questions...

    Hey all, I just picked up a 1980 XS1100, and have some real questions about its behavior. Here's the short story:

    When rebuilding the engine, I installed a Wiseco 1179cc overbore kit, along with new gaskets, etc. Following the instructions in the Clymer manual for valve timing, when starting the engine it sounds as if the valve timing is off. The engine does not spin over evenly, and when attempting to start the bike, it backfires through the carbs. I've checked, rechecked, and triple checked the valve timing, and everything lines up perfectly. The dots on the cams are pointing to the arrows on the caps, I'm aligning the pointer with the 'C' when installing the cam chain tensioner, and after rotating the engine over a few times, everything is still in alignment.

    I've come from a background of cars, have many motorcycles, and know I'm not crazy, but this thing acts like it's out of time.

    Any suggestions??

    Sean

  • #2
    First, I'd check the compression. Also, have you checked your cam to shim clearances? Did you do any head/valve work to the motor? I did a light hand lapping of my valves a while back and just that changed things 2 shim sizes.

    If everything is in time, you have some valves not closing completely for it to backfire through the carbs. Hopefully the valves didn't get bent somehow during the installation and it is just the shims that are keeping the valves open.

    And just to be sure... when the dots on the cams are aligned with arrows on the caps, the timing marker is on the "T", not the "C".. correct?
    Tod
    Last edited by trbig; 02-20-2009, 09:07 AM.
    Try your hardest to be the kind of person your dog thinks you are.

    You can live to be 100, as long as you give up everything that would make you want to live to be 100!

    Current bikes:
    '06 Suzuki DR650
    *'82 XJ1100 with the 1179 kit. "Mad Maxim"
    '82 XJ1100 Completely stock fixer-upper
    '82 XJ1100 Bagger fixer-upper
    '82 XJ1100 Motor/frame and lots of boxes of parts
    '82 XJ1100 Parts bike
    '81 XS1100 Special
    '81 YZ250
    '80 XS850 Special
    '80 XR100
    *Crashed/Totalled, still own

    Comment


    • #3
      Haven't checked compression yet, but suspect that's not the issue. When setting the cams, the pointer was on the 'T', not the 'C'.

      Haven't checked valve lash...I suppose too tight could cause some of the problems. It really sounds like cam timing from the way the engine spins over. It spins fast, and then slow, and fast, and slow.

      Just thinking about it, I think 1 & 4 were pulling a good vacuum, and 2 & 3 were not, so that may lean towards valves hung open.

      Anyway, you guys are the XS experts, not me. So I'll take any advice you can give.

      Thanks!

      Sean

      Comment


      • #4
        A motor turning fast then slow can be timing.. but could also be rotating through the 4 cylinders where a couple have compression and a couple don't. I just bought another bike that has no compression on a couple cylinders, but also has zero clearance between the cam and shim.. so it's holding open the valves.

        As far as timing though... if you find you have compression... if you remove the timing plate under that left sidecover where your pickup coils are, you will see the crank that the timing plate is attached to. There is a pin that keeps the timing plate in it's proper place that has occasionally been known to fall out. It will still be there if this is the case and just needs to be re-installed with some Yamabond or something. Here's the pin I am talking about..




        I would check for compression first though. If you don't have a gauge.. you could pull the spark plug and put your thumb over the hole and see if it blows it off while cranking. Not accurate.. but does tell you if there's compression.


        Tod
        Last edited by trbig; 02-20-2009, 09:37 AM.
        Try your hardest to be the kind of person your dog thinks you are.

        You can live to be 100, as long as you give up everything that would make you want to live to be 100!

        Current bikes:
        '06 Suzuki DR650
        *'82 XJ1100 with the 1179 kit. "Mad Maxim"
        '82 XJ1100 Completely stock fixer-upper
        '82 XJ1100 Bagger fixer-upper
        '82 XJ1100 Motor/frame and lots of boxes of parts
        '82 XJ1100 Parts bike
        '81 XS1100 Special
        '81 YZ250
        '80 XS850 Special
        '80 XR100
        *Crashed/Totalled, still own

        Comment


        • #5
          If you had the ignition pick up apart, possibly the projection on the timing advance mechanism could be off 180 degrees. This is the sleeve behind the c-clip that triggers the pick up coils. It can go on either correct or 180 off. DAMHIK.
          2H7 (79) owned since '89
          3H3 owned since '06

          "If it ain't broke, modify it"

          ☮

          Comment


          • #6
            Originally posted by bikerphil View Post
            If you had the ignition pick up apart, possibly the projection on the timing advance mechanism could be off 180 degrees. This is the sleeve behind the c-clip that triggers the pick up coils. It can go on either correct or 180 off. DAMHIK.
            I will check compression tonight. I did not have the pick up assembly apart ( no guarantees the PO didn't, though).

            Comment


            • #7
              You also might post in your personal info where you're at. You may be in an area where somebody could help you if you wanted. Most on here work for nearly free... a meal or/and a cold beverage.

              Tod
              Try your hardest to be the kind of person your dog thinks you are.

              You can live to be 100, as long as you give up everything that would make you want to live to be 100!

              Current bikes:
              '06 Suzuki DR650
              *'82 XJ1100 with the 1179 kit. "Mad Maxim"
              '82 XJ1100 Completely stock fixer-upper
              '82 XJ1100 Bagger fixer-upper
              '82 XJ1100 Motor/frame and lots of boxes of parts
              '82 XJ1100 Parts bike
              '81 XS1100 Special
              '81 YZ250
              '80 XS850 Special
              '80 XR100
              *Crashed/Totalled, still own

              Comment


              • #8
                Done.

                I'm in Bartlett, TN (a suburb of Memphis)

                Comment


                • #9
                  Hmmm... The Elvis accent didn't come across when you type.

                  Welcome to the forum by the way.. lol. We'll get you straightened out at some point. Lots of smart folks on here.. but I'm not claiming to be one of them.


                  Tod
                  Try your hardest to be the kind of person your dog thinks you are.

                  You can live to be 100, as long as you give up everything that would make you want to live to be 100!

                  Current bikes:
                  '06 Suzuki DR650
                  *'82 XJ1100 with the 1179 kit. "Mad Maxim"
                  '82 XJ1100 Completely stock fixer-upper
                  '82 XJ1100 Bagger fixer-upper
                  '82 XJ1100 Motor/frame and lots of boxes of parts
                  '82 XJ1100 Parts bike
                  '81 XS1100 Special
                  '81 YZ250
                  '80 XS850 Special
                  '80 XR100
                  *Crashed/Totalled, still own

                  Comment


                  • #10
                    Originally posted by trbig View Post
                    Hmmm... The Elvis accent didn't come across when you type.

                    Welcome to the forum by the way.. lol. We'll get you straightened out at some point. Lots of smart folks on here.. but I'm not claiming to be one of them.


                    Tod
                    Yeah...about Elvis...I'll probably get flamed for this one, but I've lived here all my life (32 years) and have never been to Graceland. The closest I've come is when I had a Mustang stolen once, and it was recovered a few blocks from there, on Elvis Presley Blvd. in fact!

                    Comment


                    • #11
                      Yup, welcome ...

                      Lots of smart folks on here.. but I'm not claiming to be one of them.
                      Now there's some BS if I ever heard any , he's damn sure one of the smart ones ... he may not be claimin' it but, trust me on this one Mustang, he's one of 'em !!

                      Nice town, Memphis is too !! In fact, once a few years ago ....

                      I was walkin' in Memphis ....
                      Walkin' with my feet ten feet offa' Beal ...


                      80G Mini-bagger
                      VM33 Smooth bores, Pods, 4/1 Supertrapp, SS brake lines, fork brace

                      Past XS11s

                      79F Stone stocker and former daily driver, sold May '10 now converting for N.O. to cafe style
                      79SF eventually dismantled for parts
                      79F Bought almost new in 80, sold for a house
                      79F The Ernie bike sold to a Navy dude summer 08
                      79SF Squared-off Special, Vetter/Bates tour pkg., Mikes XS coils, G rear fender and tail light. Sold June 09

                      Comment


                      • #12
                        Well ... actually, I .....

                        Yeah...about Elvis...I'll probably get flamed for this one, but I've lived here all my life (32 years) and have never been to Graceland
                        .... Saw the ghost of Elvis down on Union Avenue ...
                        Followed him up to the gates of Graceland ....
                        Watched him walk right through ...


                        I'm loosin' it, I think ???
                        80G Mini-bagger
                        VM33 Smooth bores, Pods, 4/1 Supertrapp, SS brake lines, fork brace

                        Past XS11s

                        79F Stone stocker and former daily driver, sold May '10 now converting for N.O. to cafe style
                        79SF eventually dismantled for parts
                        79F Bought almost new in 80, sold for a house
                        79F The Ernie bike sold to a Navy dude summer 08
                        79SF Squared-off Special, Vetter/Bates tour pkg., Mikes XS coils, G rear fender and tail light. Sold June 09

                        Comment


                        • #13
                          he's damn sure one of the smart ones

                          Well.. He has HALF of that word right..

                          So what did you find out?


                          Tod
                          Try your hardest to be the kind of person your dog thinks you are.

                          You can live to be 100, as long as you give up everything that would make you want to live to be 100!

                          Current bikes:
                          '06 Suzuki DR650
                          *'82 XJ1100 with the 1179 kit. "Mad Maxim"
                          '82 XJ1100 Completely stock fixer-upper
                          '82 XJ1100 Bagger fixer-upper
                          '82 XJ1100 Motor/frame and lots of boxes of parts
                          '82 XJ1100 Parts bike
                          '81 XS1100 Special
                          '81 YZ250
                          '80 XS850 Special
                          '80 XR100
                          *Crashed/Totalled, still own

                          Comment


                          • #14
                            Took everything apart again, put it all back together, and it works. Didn't change any settings, and everything was in time when I started, but it works now... oh well!

                            Thanks for all the help, y'all!

                            Sean

                            Comment

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