1999 wont rev, 5 days to fix it

Discussion in 'Mechanics Garage' started by wiso, May 10, 2020.

  1. Terry Smith

    Terry Smith Member

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    I have a feeling that you might be on a wild goose chase with the ECM. The idle screw and SVs are all linked with the "choke"; the choke and the idle screw do the same thing, as you screw the idle in/open the choke lever, it lifts the starter valves open and allows more air into the engine to raise the engine speed . The SV's are controlled "air leaks" that bypass the butterflies, and the butterflies will normally be full closed at idle.

    Maybe you have got other air leaks that you don't know about that are throwing the fueling off (making it lean) and hence the reluctance to rev? I'm thinking about the isolator boots or any of the miles of little rubber hoses in the TB area. Are the SV synch hoses properly capped off?

    The service manual is very unhelpful about the screw starting position of the SVs, but it does specify a manifold vacuum of 200-250mm Hg at idle. The 5G is also unique in that the SV's are not meant to be synched to the same vacuum on all 4. #1 and 2 should be the same, 3 should be 20mm dropped from #1 and 4 should be 10mm dropped. Not sure that that will have any impact on the relcutance to rev however, just off-idle response.
     
  2. wiso

    wiso New Member

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    No other leaks. The timing is off when checked with a timing light.
     
  3. raYzerman

    raYzerman Member

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    Well, maybe a little caution on being too hung up on timing, but let's get anal for a sec. RPM can throw this off, so if you have a digital tach that can give you true RPM, it would be interesting to know exact timing at 100 rpm intervals, starting at 1000 and going up to say 14oo, and to see that behaviour is normal at 2000 (per the manual, although that is vague they don't give you an actual timing value). Just thinking the timing actually may be "OK" for the most part.
    All parameters ultimately control injector pulse and duration. Wondering if we're heading for having the injectors checked for spray pattern and flow and cleaned..... how would you flow after 21 years..... may not be a problem, but might be worth having them checked anyway. As for me, I take meds to help me pee, LOL, and I don't know how old I am in bike years....
    First thing I would do though, is do a proper starter valve sync and get that out of the way, and it's cheap. I don't think any of us know where (RPM) that tapers off to having little effect, you're seeing your issues at 6000, maybe that's close to the cut-off, dunno.
     
  4. wiso

    wiso New Member

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    All the fuel injectors have been replaced the timing stays the same until 2000 rpm when it advances as it should but the time is still off by 10 to 15゚ across-the-board
     
  5. wiso

    wiso New Member

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    Fixed. Both rear cams were off by one tooth.
     
  6. RllwJoe

    RllwJoe Insider

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    So, the valve timing was off! Glad that you have it sorted out. Now ride like the wind.
     
  7. wiso

    wiso New Member

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    Not so much the valve timing as the cam phase sensor reads the rear intake cam position, which then set the entire engine timing off.
    Other than the pile of money i wasted trying to figure it out, at least I have a 21 year old bike with a bunch of new parts in it.
    Live and learn....
     
    Last edited: Jul 27, 2020
  8. Diving Pete

    Diving Pete Member

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    So someone had removed the camshafts & reinstalled them incorrectly....
     
  9. wiso

    wiso New Member

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    Yes. That person was me. I will never know if they were in correctly before I adjusted valves, as it ran the same way before I did the adjustment.
    I am just glad its fixed as we are going on another trip in a couple weeks.
     
  10. Diving Pete

    Diving Pete Member

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    Glad to hear you got to the bottom of this..
     
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