KDRider
New Member
I wanted to share this in case anyone else has the same thing happen.
SYMPTOM
I was riding along about 50mph not pushing the bike at all, on a hot 90+ degree day here in FL. The bike was running great. It's a 2012 bike with about 14,000 miles. Without warning, it sounded like the exhaust had developed a hole in it (???). I stopped took of the helmet to see where the sound was coming from. It was coming from the airbox!!??!!
At idle it sounded normal, but under any kind of load it had a ton of noise coming from the airbox. A noise that sounded like exhaust noise.
The bike ran like crap as I nursed it home.
CAM CHAIN HAD SKIPPED A TOOTH
The only thing that made any kind of sense was that I had a problem where my intake valves were remaining open at the wrong time. ….and sure enough that was exactly what was going on because I found that my cam chain had slipped a tooth. (Yikes!)
To find that the cam chain had skipped a tooth I pulled the plastic over from the right side of the engine that allows you to see the timing marks on the end of the cam shaft, and then I rotated the engine to where the #1 cylinder was at TDC. The timing mark on the end of the cam was of by a few degrees from where the factory manual shows it should be. I rotated the flywheel so #2 was at TDC and not surprisingly the timing marks on the cam were off by a few degrees again.
FAILED TENSIONER
I didn’t see anyone on the forum with a slipped cam chain who had posted. But I did see itlives posted where he had a cam tensioner fail. I pulled my tensioner out, and found that the spring in the tensioner had broken. This was certainly the reason that my cam chain had slipped.
Even with cam tensioner out of the bike, I didn’t have enough slack in the cam chain to slip it back. (I tried from the cam sprocket end, as well as the crankshaft end). I had to take the sprocket off the end of the cam shaft and move the chain back one tooth, and put it all back together. I confirmed that the cam timing marks were perfect once again at TDC for both cylinders.
BACK TO GOOD AS NEW
I bought a new tensioner (about $100) and installed it per the factory manual instructions, put everything back together, crossed my fingers and fired it up. I’m happy to say that it runs a good as new now.
Actually, the engine is now a bit quitter than it was before, and I suspect it must have been running with a loose cam chain for some time before the slip actually happened. I'm definitely going to check that tensioner each time the valves are adjusted from now on.
SYMPTOM
I was riding along about 50mph not pushing the bike at all, on a hot 90+ degree day here in FL. The bike was running great. It's a 2012 bike with about 14,000 miles. Without warning, it sounded like the exhaust had developed a hole in it (???). I stopped took of the helmet to see where the sound was coming from. It was coming from the airbox!!??!!
At idle it sounded normal, but under any kind of load it had a ton of noise coming from the airbox. A noise that sounded like exhaust noise.
The bike ran like crap as I nursed it home.
CAM CHAIN HAD SKIPPED A TOOTH
The only thing that made any kind of sense was that I had a problem where my intake valves were remaining open at the wrong time. ….and sure enough that was exactly what was going on because I found that my cam chain had slipped a tooth. (Yikes!)
To find that the cam chain had skipped a tooth I pulled the plastic over from the right side of the engine that allows you to see the timing marks on the end of the cam shaft, and then I rotated the engine to where the #1 cylinder was at TDC. The timing mark on the end of the cam was of by a few degrees from where the factory manual shows it should be. I rotated the flywheel so #2 was at TDC and not surprisingly the timing marks on the cam were off by a few degrees again.
FAILED TENSIONER
I didn’t see anyone on the forum with a slipped cam chain who had posted. But I did see itlives posted where he had a cam tensioner fail. I pulled my tensioner out, and found that the spring in the tensioner had broken. This was certainly the reason that my cam chain had slipped.
Even with cam tensioner out of the bike, I didn’t have enough slack in the cam chain to slip it back. (I tried from the cam sprocket end, as well as the crankshaft end). I had to take the sprocket off the end of the cam shaft and move the chain back one tooth, and put it all back together. I confirmed that the cam timing marks were perfect once again at TDC for both cylinders.
BACK TO GOOD AS NEW
I bought a new tensioner (about $100) and installed it per the factory manual instructions, put everything back together, crossed my fingers and fired it up. I’m happy to say that it runs a good as new now.
Actually, the engine is now a bit quitter than it was before, and I suspect it must have been running with a loose cam chain for some time before the slip actually happened. I'm definitely going to check that tensioner each time the valves are adjusted from now on.