Author Topic: First GTO rides - Vibration, any suggestions or thoughts?  (Read 425 times)

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Offline BRT-GTR

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First GTO rides - Vibration, any suggestions or thoughts?
« on: August 28, 2017, 10:22:11 AM »
      GTO imported from States, previously rebuilt engine (by good builder), NOS carbs and many new parts. Have gone through the bike, checking, refurbing, cleaning, lubing, adjusting, etc to put her in as good a mechanical condition as I can get it. Has new pistons in old bores. Probably genuine 3K on the clock but not original engine. New coils, points and condensers fitted.

     Took her for first ride the other evening keeping the revs down below 4000.  Running very rich, better when pulling or on the overun but coughing and spluttering at light load.  Pulls well low down but after warming up was reluctant to accelerate over 45-50mph, as though she was running on one cylinder. Engine generally noisy with more vibration than I would like or remember, thought left cylinder didn't sound right, not coming on song. Good news - the brakes  are brilliant.

  So, put in alternative coils,  new condensers, plugs and pulled the left disc cover. Disc reluctant to come out, but with a couple of thin blades was able to gently work it off the splines. Couldn't  budge the pin holding the disc collar. Now it is my understanding the discs should be free to move laterally on the collars so they can seal against the outer cover on primary compression. Problem ? the base of the collar splines had been 'sealed?' with loctite. Disc was stuck solid.  So freed it off and refitted. Also dropped carb needles to second slot.  Has significantly improved the starting/idle and a slight improvement on top end but still vibrating. (Checked the right disc when a wobbly clutch drum was replaced, looked like something may have jammed the primary drive in the past?),

    I'm running out of ideas but this may be significant. Although the primary gears are correctly timed, I had to turn the alternator and points plate fully clockwise to time  the ignition. Couldn't quite get both sides spot on using crank dimples , maybe a degee or two imbalance, so split the difference   . Will check the timing on the pistons today.               There is very slight play in the main case bearing behind the clutch but I'm beginning to wonder if the crank has 'moved'.     Any other suggestions ?

  Brian, not a happy bunny at the moment.
         
« Last Edit: August 28, 2017, 03:10:18 PM by BRT-GTR »
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