koth442 Posted May 21, 2018 Share Posted May 21, 2018 Yes, that is pretty typical to see differences in cam chain tension when rotating by hand. 2 reasons: first, you can’t spin it fast enough by hand to keep up with the rotational speed of the cams rotating on their own, pressured by the valve springs and lobes. Second, and more importantly is that there is a chain guide built into the valve cover which puts pressure on the chain right where the tension changes between the sprocket gears when the cover is installed. But of course you can’t really watch the tension when the valve cover is installed though..... When the engine is running, everything smooths out and the oil flow to the tensioner allows the tensioner to “dampen” much of that fluctuation in chain tension. Just theories, I’m not an engineer. YouTube probably has videos though. -Skip I am an engineer and I approve this message '15 FJ09 Link to comment Share on other sites More sharing options...
Premium Member 2and3cylinders Posted May 21, 2018 Author Premium Member Share Posted May 21, 2018 Before I started this round of maintenance, I installed the APE manual CCT. Previoualy, I had the supposedly appropriate TSB OEM replacement "automatic" CCT kit installed by my dealer (who told me they could not give me the kit to install myself per Yamaha but Nielsen Enterprises, Lake Villa, IL is still a very good company). This kit included a different valve cover bolt and tear-drop shaped sealing "washer" I believe are intended to improve oil flow to the CCT. Will leaving the TBS CCT kit special bolt and washer be an issue with the APE CCT? Link to comment Share on other sites More sharing options...
nsmiller Posted May 21, 2018 Share Posted May 21, 2018 Following this thread. Edit: I agree the cam shafts look normal to me. Link to comment Share on other sites More sharing options...
duhs10 Posted May 21, 2018 Share Posted May 21, 2018 ... This kit included a different valve cover bolt and tear-drop shaped sealing "washer" I believe are intended to improve oil flow to the CCT. Will leaving the TBS CCT kit special bolt and washer be an issue with the APE CCT? I had this same question and was told that it would not be a problem... I haven't noticed anything abnormal (although I'm not sure I would if something was abnormal) If you are worried about it, just order a valve cover bolt for one of the other locations and replace the TSB bolt install. https://fj-09.org/post/76734/thread '15 FJ-09 w/ lots of extras... Fayetteville, GA, USA Link to comment Share on other sites More sharing options...
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