Help! R1100RS with dead cylinder

Discussion in 'Road Warriors' started by jameswhitaker, May 5, 2012.

  1. jameswhitaker

    jameswhitaker Adventurer

    Joined:
    Apr 20, 2012
    Oddometer:
    24
    Location:
    Seattle
    I just got done replacing the clutch on my R1100RS and got it put back together, but I now can't make it run right. The right cylinder is dead and I don't know why. What I have checked:

    Spark - good
    plug wires (replaced last year) still match impedance
    plugs - match impedance
    Valve clearance, there was little or no input valve clearance on right cylinder, now clearances are set correctly. The exhaust side was tight, but not crazy tight.
    compression: right was 90, left 120 with throttle closed. Right is now 110ish, 120 ish with fast start open, though leak down is faster than with right cylinder - compression is still noticeably weaker on right side.
    The right cylinder occasionally backfires through the throttle body, though less than when I first tried to start it.
    The right cylinder blows puffs of air out the throttle body while idling
    detaching the right fuel injector has no effect on idle, left FI detachment kills bike
    fast start idle idles at about 1000RPM
    right cylinder and plug are cold after engine has warmed somewhat
    spray patterns of both fuel injectors appear good

    Do I have a sticking valve? Is it possible for the cam sprocket to have slipped out of adjustment?

    Some background on the bike. A friend of mine had this bike sitting in his driveway for 4 or 5 years without riding it. He gave it to me and I have since replaced the battery, starter, front master cylinder, clutch, brake pads, plug wires, oil, and maybe other things I have forgotten. The bike was running OK last fall/late winter when i put it in my garage (November?), intending to replace the clutch before I rode it again. I remember that last summer the compression on the right cylinder was a bit low (110?) and that it would occasionally backfire on the overrun, so I thought it needed a valve adjustment (it did) but other than that everything seemed just peachy. I did not start the bike up before beginning the clutch replacement a few weeks ago. Yes, it's true that the gas is still 6 months old and, if I thought it would help, I would burn the gas in my slant six pickup (which would probably burn gas from 1962 with no complaints) but the left cylinder doesn't seem to mind the old gas and I don't think old gas is causing the right cylinder to breath backwards...

    I am just about at the end of my patience for this bike and am considering parting it out to fund its replacement with something reliable - like maybe a BSA... I am willing to pull the right head to see what might be the difficulty, but I am reluctant to continue to throw good money after bad. I am hoping someone might have some insight here as I am still curious to know what it might be like to ride this bike when it's running right.

    Oh, and I was unable to find any place on the forum where I could post stuff about my RS, but I figured that since the engines are pretty much the same it shouldn't make any difference.
    #1
  2. Mrmerlin

    Mrmerlin K1300S fast as shi..

    Joined:
    Oct 16, 2009
    Oddometer:
    341
    Location:
    Philly PA
    remove the intake tube and open the throttle plate,
    spray about 1 second of ether into the intake and start the bike if it fires then you have fuel issue,
    you could swap the fuel injectors side to side. and crank the bike over with injector on the right side in a jar with a rag see if fuel is coming out of the injector.
    Maybe you pinched or cut a wire for the injector
    Also adjust the valves to add .002 to the clearances of both sides
    intake .008 make it .010
    EX .012 make it .014

    Check the intake collar of the throttle body if it has an OI ring seal then check the O rings for being pinched
    #2
  3. jameswhitaker

    jameswhitaker Adventurer

    Joined:
    Apr 20, 2012
    Oddometer:
    24
    Location:
    Seattle
    Thanks for the advice, I've already checked both fuel injectors for delivery. I've already determined that both cylinders have fuel, compression, and spark, but only the left cylinder is burning. Also, I assume that the factory valve clearance spec should be adequate for the bike to run, at least :-)

    I haven't had the throttle body off since it was running correctly, so I doubt that the o-ring tangled itself and caused this problem in the meantime, but I will be pulling all of that apart soon if I can't get this thing to behave, so I'll keep an eye out.
    #3
  4. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,753
    Location:
    N.W. Arkansas
    before you replaced the clutch, it ran well?

    all other logic and variables aside, if its been sitting for 4-6 years and you think it has bad gas in it, i would certainly start there.


    drain that shit put it in a bonfire, your hoopty whatever.

    replace the rubber lines inside the tank, along with the internal fuel filter, refill with some fresh gas and then go ride it.
    #4
  5. vagueout

    vagueout Long timer

    Joined:
    Mar 3, 2010
    Oddometer:
    1,811
    Location:
    sydney, east
    Have you checked that your throttle cable ends are seated correctly????:wink:
    #5
  6. jameswhitaker

    jameswhitaker Adventurer

    Joined:
    Apr 20, 2012
    Oddometer:
    24
    Location:
    Seattle
    Let's see, just to clarify, the gas is perhaps 6 months old. I rode the bike around last summer. Also, yes, I've checked the throttle cables. Also, please note that one cylinder is running well, the other is not only not firing, but is blowing air back out the throttle body, which the other cylinder definitely does not do.
    #6
  7. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,753
    Location:
    N.W. Arkansas
    I guess you have it all figured out then.

    it must be broke.


    It is hard to imagine letting gas sit 6 days in my tank, let alone 6 months.


    no seriously, lets get nuts to wrenches here.


    clutch R n R should not have changed your cam chain relationship, so what DID you change, that was in front of the clutch during this procedure?


    wait... you rode the bike around last summer, but now it has low compression issues? after a clutch job?
    and you are blaming the bike?

    I think if you give all of the details, your issue will be solvable
    #7
  8. jameswhitaker

    jameswhitaker Adventurer

    Joined:
    Apr 20, 2012
    Oddometer:
    24
    Location:
    Seattle
    I'm not sure what I said that you take umbrage to, I'm only trying to clarify what I wrote. If I had it all figured out, I would not have asked for help. I'm frustrated that I put all of the details I can think to put in the first message and every post I have gotten in reply seems to indicate that the person posting did not read the initial post.

    If there is information that would be helpful that I didn't post, I'm happy to go see if I can fill in the details. I didn't write this post to troll. I really am looking for someone experienced enough with these bikes that they might have encountered a similar situation before.

    I do appreciate the time people put in to try to help, and I am trying hard to be polite in restating facts that are stated in the initial posting, such as the fact that the bike also had low compression on the right cylinder when I got it, but that it has worsened over the winter, in garage storage. Also, I know that what I write is not always clear but I thought that I gave some pretty thorough diagnostics in the posting.

    I'm sorry if my tone about the quality of this bike has offended you. I really do want to believe that this bike will be a great bike someday, but from what I have seen of it so far, it is a pale imitation of my old R100RS in terms of quality and reliability. I am feeling pretty burned with all of the money I have thrown at parts from the dealer that should have been cheaper and lasted longer. I hope I can soon prove myself wrong.

    I'm glad that you never leave gas in your tank for more than 6 days. I don't have the means to toss out gas older than 6 days and I don't have need to drive the truck that much. My car, being a diesel, doesn't so much like gasoline. All of that aside, If the left cylinder runs fine on this gas, would you have an explanation for why the gas would cause the right cylinder to be blowing air back through the throttle body?

    I did the clutch job pretty much exactly the way the factory manual told me to, which is to say that I didn't fiddle with any engine systems, apart from detaching and reattaching the bowden cable between the TB's and disconnecting the airbox from the TB's. Also, at the time of the clutch job, I did a canisterectomy as I discovered that the connections on the canister to the fuel tank vent lines were rusted off. After discovering this problem with the right cylinder I put lines and purge valve all back just to see if there was any effect. There was not. And yes, I plugged the vacuum ports on the TB's with vacuum caps.

    Upon further reading about the cam chain and timing system, I am also convinced that the cam timing having shifted is a somewhat unlikely scenario. Has anyone had a sticky valve cause anything like this before?

    If you don't know, it's OK to say you don't know.
    #8
  9. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    6,059
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    yes.... nothing quite so reliable as a BSA :rofl.


    sounds like you've covered it pretty well....

    did you try swapping the plugs and leads left to right? that would double check those components under operational conditions and tell you if its ignition. if that stuff is good but the problem persists the coil could have an insulation break down & only fire one side intermittently under load

    other than that... "detaching the right fuel injector has no effect on idle" would seem to me to be the next thing to chase... again swapping injectors left to right
    #9
  10. Zoef zoef

    Zoef zoef Been here awhile

    Joined:
    Apr 19, 2009
    Oddometer:
    420
    Location:
    Finnøy Island, near Stavanger, Norway
    Sir,

    You may want to check the seating again of the throttle cables on the right side. Sometimes, it can be very hard to tell if they are correctly seated.
    Another thought, have you tried switching the spark plugs around? Possibly one can be malfunctioning when under pressure.
    #10
  11. jameswhitaker

    jameswhitaker Adventurer

    Joined:
    Apr 20, 2012
    Oddometer:
    24
    Location:
    Seattle
    Yes, I'm glad someone got the humor.

    Anyway, yes I did swap plug wires and plugs in all the combinations and there was no difference. I have also looked at both the injectors spray pattern attached to their own side connections and they appear identical. I'm interested in the idea that the different sides of the coil may be behaving differently. I guess the next thing to do is to cross the plug wires as I think they have enough slack in them to do that. Also, I will definitely try swapping the FI's.

    No one yet seems to have thought that the fact that the right throttle body is blowing back air (fuel/air mixture) is unusual. Am I crazy? is this normal for one cylinder to do this and not the other? I understand that, at idle, the valve overlap could cause a back pulse to the intake side, but you can feel this pulse prominently from 3-4" from the TB on the right side and not the other. This would seem to indicate to me that at least one of the intake valves, if not both, was still open through a substantial duration of the compression stroke. It has occurred to me that a dirty guide could slow the valve action enough to cause this at idle speed, but perhaps still give me some compression at slower, cranking speed. Does this sound like crazy talk?
    #11
  12. jameswhitaker

    jameswhitaker Adventurer

    Joined:
    Apr 20, 2012
    Oddometer:
    24
    Location:
    Seattle
    Unfortunately, I have fiddled and fussed over that cable quite a lot and even held the outer sleeve in the adjuster while running and playing with the throttle just to make sure it wasn't doing something under running conditions that it wasn't doing statically. I'm still not sure I didn't bugger something up with that, but I guess I don't know what else I might do. It does appear that both TB's move simultaneously with throttle motion...
    #12
  13. Cogswell

    Cogswell Spudly Adventurer

    Joined:
    Jan 3, 2005
    Oddometer:
    4,785
    Location:
    Riding with my pal Richard Cranium
    Have you removed the cylinder head covers and verified the correct cam timing ? That would at least take that question out of the mix.

    Have you checked the HES ? those are pretty notorious for failure in the early models.

    Mike
    #13
  14. Mrmerlin

    Mrmerlin K1300S fast as shi..

    Joined:
    Oct 16, 2009
    Oddometer:
    341
    Location:
    Philly PA
    No one yet seems to have thought that the fact that the right throttle body is blowing back air (fuel/air mixture) is unusual. Am I crazy? is this normal for one cylinder to do this and not the other? I understand that, at idle, the valve overlap could cause a back pulse to the intake side, but you can feel this pulse prominently from 3-4" from the TB,

    Thats why I suggest to increase the valve clearances.

    Before that it might be an idea to check the coils and swap them side to side,
    also see if the coils are both getting 12v power thats if you have 2 coils.
    installing a new set of spark plugs may also be a good idea as they can foul.
    #14
  15. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,753
    Location:
    N.W. Arkansas
    my own self admitted lack of reading comprehension, coupled with your own self admitted unclear typing.. not a problem.

    Ok, so blow back throught the throttle body, and low compression on that cylinder, have you done a leakdown test on that side?

    assuming the valve clearances are within spec, perhaps the intake valve is bent, or an exhaust valve is burnt, although that would huff out the exhaust I would think.

    I think quick and dirty leakdown test will tell the tale.

    use the same hose from your compression guage, put that cyinder at TDC, bike in neutral, start at 0 psi, and slowly increase the pressure, listening to the TB and the EX you should be able to hear where the combustion chamber is leaking too..

    If its hissing from the oil fill hole, its a ring seal issue.

    careful though, once doing this, I had the pressure up to about 60 psi, and the suzuki samuri I was working on lurched forward about a foot..
    #15
  16. Steve W.

    Steve W. Boxer Pilot

    Joined:
    May 14, 2005
    Oddometer:
    335
    Location:
    Upstate South Carolina
    Go back to the valve clearance. I think I read that you adjusted the valves before the clutch job? And never ran it? The right side could have been on the exhaust stroke and appeared too tight. When set now they are too loose to operate. If left side is good clearance at "tdc compression" then right is on "tdc exhaust" valves open. Turn crank another turn to right side "tdc compression".
    Just a thought.
    Cheers and happy hunting.
    Steve
    #16
  17. jameswhitaker

    jameswhitaker Adventurer

    Joined:
    Apr 20, 2012
    Oddometer:
    24
    Location:
    Seattle
    Actually, the left cylinder is running fine. It is the right cylinder which had all of the problems and I adjusted the valves on that cylinder after the clutch job. I am positive that I had the right cylinder on TDC firing when adjusting, but it never hurts to recheck. Still, I'm a little confused at how it would be possible to adjust the valves while they are open. You wouldn't think it would possible to insert the feeler gauges...

    mouthfulloflake, on your advice I did put together a little leak down test setup at the hardware store just now and I'll haul my room mate's compressor down to the garage tomorrow to do the leakdown test. I have a friend who used to have a boroscope and maybe I can get a look at the inside of the combustion chamber with that, too.

    I did think about the burnt exhaust valve, but the exhaust side still had clearance and, like you, I didn't think it would cause compression loss to the intake side. I am still leaning to the sticking intake valve theory, and I can't think of how to test that theory if it only appears at idle speed and above (floating valve, in other words.) I'm not sure it's a good idea to idle the bike with the valve cover off (after all, this isn't a 1962 Rambler) and it seems like it might get messy fast, and then you would grind the engine to dust once all your oil was on the floor...

    I'm tempted to add some Marvel mystery oil to the crankcase oil and just idle the bike for a few minutes a day until the valves start behaving, but I'm concerned about what kind of damage could be done by idling the engine with only one cylinder firing. Anyway, I have some previous commitments today, so I may not be able to try everything people have suggested until tomorrow. Unfortunately, my garage is about a mile away on the other side of a drawbridge and this weekend is first day of boating season, so there is a lot of nasty traffic between here (my computer) and there (my bike and tools.)
    #17
  18. johnjen

    johnjen I've Been Resigned

    Joined:
    Nov 28, 2001
    Oddometer:
    16,254
    Location:
    Seattle
    Just to be clear here.

    You did rotate the engine 360º after checking the valves on one side to then check the valves on the other side?

    Have you checked the compression with the throttle wide open, and not closed?

    When you close the throttle do you hear 2 clicks or one?
    and
    Have you made sure that when the throttle is closed (& fast idle lever is off) both throttle shaft cam plates are resting on their respective stop screws?

    JJ
    #18
  19. ttpete

    ttpete Rectum Non Bustibus

    Joined:
    May 13, 2009
    Oddometer:
    6,249
    Location:
    Dearborn, MI
    Do you have any compression on the dead cylinder? It has to be low if you're getting blowback through the throttle body.

    What do the intake valve adjusters look like from side to side? Do they look different? Measure intake valve spring height from side to side. Any difference? My thought is that you may have a stuck valve from sitting without running for a time. You could also have a stuck valve that has had piston contact and is bent.
    #19
  20. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    6,059
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    you could check for a sticking valve by pushing on them.... piston at BDC (or at least not TDC) and push on them one at a time with a big dowl or something. If they have any tendency to stick I would think it would be apparent.

    I believe you have checked the valve clearance and timing & that there is some compression. That doesn't leave much

    as for the ignition box... it triggers the single coil to fire both plugs at the same time.... one cylinder is in power stroke, the other is in exhaust. if one side runs good, then the brain box and pickup coil must be good. the sparkplug coil may have a weak spot in the insulation of the secondary winding. this could cause the plugs to fire fine when out of the cylinder but due to higher resistance under pressure when installed, part of the secondary pulse shorts inside the coil instead of going to the plug... gropin a bit here, but a possibility. if coil is bad but the wires & plugs are good, the problem should switch sides if you change the wires. Or you might try an ohm reading from either plug wire socket (at the coil) to ground.... it should be infinite, and even a reading in the 10k range would be suspect. a "good" reading may not be accurate though since high 2nd voltage will jump gaps, cross insulation and find paths that an ohm meter can't read.

    I've owned many BSAs.
    #20