Michael B Posted September 8, 2014 Share Posted September 8, 2014 My 2011 RT has over 40K on the clock. I change synthetic motor oil every 3,500 miles and am particular about maintenance. A month or so ago I noticed a small "rattle" that sounded like something loose upon cold startup. It's gotten louder. It lasts for about a minute or so, then gets a little quieter, and is almost gone when at operating temps. A little throttle makes it go away. I removed all front plastic and couldn't find anything loose. It seems to be coming from just behind the left cylinder head (sitting on the bike) with no rattle behind the right cylinder head. One of my riding buddies thinks it is a chain tensioner going bad, but that's only a guess. It's an ugly sound to me. Would appreciate any help here! Thanks much. Link to comment
cris nitro Posted September 8, 2014 Share Posted September 8, 2014 I would agree, but I thought the camheads received the upgraded tensioner? Link to comment
mneblett Posted September 8, 2014 Share Posted September 8, 2014 Neither my '09 hexhead RT nor my '12 camhead RT had such a rattle. I'd suggest getting a dealer's ear on it, as this is not "normal." Link to comment
Michael B Posted September 23, 2014 Author Share Posted September 23, 2014 Problem resolved. It was, believe it or not, the viscosity of my motor oil! I was running 10W40 full synthetic as my summer oil (reference a previous "10W40 vs 20W50 for Summer" string a couple months back). The rattle upon cold startup was coming from the chain tensioner behind the left cylinder head (sitting on the bike). The rattle was rather loud and would last until drive off. Took the bike to a local independent repair shop that specializes in BMW's and left it overnight. The owner and I started it the next morning and he said the rattle from the chain tensioner was caused by the wrong weight motor oil. He suggested I put in 15W50 synthetic and the rattle should disappear. I did as suggested the same day, and the cold start rattle immediately got shorter and after a dozen or so startups is gone. The man is a genius! Just wanted to let you guys know that motor oil makes a difference…as we all know from exhaustive oil strings on this forum. Case closed! Link to comment
dirtrider Posted September 23, 2014 Share Posted September 23, 2014 Afternoon Michael Let us know how that works out long term as you get some miles on that 15w50 & it shears down to a lower viscosity. Link to comment
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