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87881Re: [TriumphTrophy] RE: Correct cam chain installation

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  • Samuel Crider
    Dec 9, 2013

      Hi Miles,

      Sounds like a logical conclusion to me. That tensioner spring is of major importance. It's unbelievable that the spring alone is not sold on this side of the pond. Just replacing it made an alarming difference in engine noise levels. For the first time since I've owned her. She now sounds close to what I'd expect a new engine to at idle. Luckily, upon close inspection all of the internals look good. Can't see any difference in the new sprockets when compared to the used ones. Even the chain looks great. So, I think I'll just replace the chain and tensioner guide. And ebay the new sprockets. Went over all the valves and logged the readings. A few are pretty tight. One intake was under a .004. Which is the smallest feeler I currently own. I figure I'll go over them again just to be sure it's all straight. Also, unfortunately I borrowed a snap-on compression tester which promptly blew a hose. Bloody thing sounded like a pistol discharging right next to my ear. So, I just today gutted an old spark plug and silver soldered a diy compression tester. Now I can do a before and after just to be safe. Anyone know what would be considered the normal range for compression readings? She was up around 100psi when the hose cut loose. I just scanned over the good book of haynes and didn't notice any data.

      Thanks to all the prompt replys. A2 I'm glad you pointed out the mark is separate from the lobe. Seems my brain wasn't keying in on this very  important fact.

      This group is a wonderful, priceless resource. Many thanks to all for the help. I'm off to get back wrenching.

      Samuel
      96 BBBB PB
      New Orleans

      On Dec 9, 2013 5:33 AM, <miles.a.french@...> wrote:


      Sam, I’ve been looking into this (because I’m supposed to be working). If our engines were both one tooth out, with the crank rotated one tooth clockwise, then we have retarded valve timing, which should result in hard starting, spitting and backfiring, but runs OK with the power band shifted up the rev range, with overheating and possible dieseling on shut-down.

      It is possible I had all these symptoms to a slight extent, except the dieseling. I thought my issues with starting and a slight misfire, (only when I feathered the throttle open just a crack), were due to a dirty pilot jet.

      Could it be that our cam chains were a bit stretched or the tensioner a bit slack, allowing the crank to jump one tooth ahead at some point, probably high-revs acceleration? The resultant localised overheating could have degraded the oil, allowing my big end to suffer. We need a fly on the cylinder wall.

      Miles



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