NancysToy
Motorbike Professor
Friday, while in another city, I picked up a stone in the rear sprocket. I was passing an area where they were chip sealing the other lane, and must have picked up a stray or two. I immediately heard a loud clicking, and felt a strong vibration ort thumping. Before I could pull to the side, I had a strong jerk like I lost a gear or a belt tooth, and then heard a "zing" as a stone apparently exited stage left. The clicking ceased. I pulled off on the first street and examined the belt and sprockets as best I could without tearing off the body panels at the side of the road, but I saw nothing. No holes in the belt, either. Foolishly, I proceeded. I still had a substantial vibration, but it did get better as I rode, and I was able to do 50-55 without shaking my eyeteeth out. I decided to proceed the 60 miles to home. In retrospect, it was stupid, but it worked out.
Over the weekend I stripped the body panels and took a better look. The belt tension was tight in one spot on each turn of the rear wheel. I found a 3/8" stone stuck in the rear sprocket. The belt was "bruised" (marked) on every tooth, with a shallow indentation on each tooth. There were no holes or tears. I ordered a new belt, and decided to try this one for a while. I dug out the stone. The sprocket was not damaged, save a little "catch" that I could not see but could feel with a screwdriver. The belt was pretty loose to begin with, and that may have saved me. It was far looser by the time I reached home, and the belt had wandered slightly. Despite proper torque on the axle bolt, I'm sure the axle moved a tiny bit.
I realigned the belt, and adjusted the tension. The Spyder is running fine, and is as smooth as when it was new! That was both a relief and a surprise. In the process of inspecting the Spyder, I had found numerous small bits of tar on the tops of some sprocket teeth. These were very flat and hard. I scraped them off and cleaned the sprocket well. I had been noticing an increasing vibration over the past few months. Nothing earthshaking...I just figured my motor mounts had settled and the engine was hitting the frame a bit. I was very surprised that in cleaning the sprocket, that vibration was completely gone! The tar must have been there a while.
Lessons were learned here...even for an old hand like me:
1. If something is obviously wrong, find a place where you can do a proper inspection, or get the Spyder towed in. I could easily have blown a belt on the way home, and been stranded. This is not an old Triumph or Harley that you can limp home on a wing and a prayer. I was lucky!
2. If you have an increasing or annoying vibration, especially at highway speeds, take a close look at the rear sprocket. Evidently any buildup of road debris on the tops of the teeth can cause some vibration. I suspect a non-concentric, warped, or damaged sprocket could do much the same.
Over the weekend I stripped the body panels and took a better look. The belt tension was tight in one spot on each turn of the rear wheel. I found a 3/8" stone stuck in the rear sprocket. The belt was "bruised" (marked) on every tooth, with a shallow indentation on each tooth. There were no holes or tears. I ordered a new belt, and decided to try this one for a while. I dug out the stone. The sprocket was not damaged, save a little "catch" that I could not see but could feel with a screwdriver. The belt was pretty loose to begin with, and that may have saved me. It was far looser by the time I reached home, and the belt had wandered slightly. Despite proper torque on the axle bolt, I'm sure the axle moved a tiny bit.
I realigned the belt, and adjusted the tension. The Spyder is running fine, and is as smooth as when it was new! That was both a relief and a surprise. In the process of inspecting the Spyder, I had found numerous small bits of tar on the tops of some sprocket teeth. These were very flat and hard. I scraped them off and cleaned the sprocket well. I had been noticing an increasing vibration over the past few months. Nothing earthshaking...I just figured my motor mounts had settled and the engine was hitting the frame a bit. I was very surprised that in cleaning the sprocket, that vibration was completely gone! The tar must have been there a while.
Lessons were learned here...even for an old hand like me:
1. If something is obviously wrong, find a place where you can do a proper inspection, or get the Spyder towed in. I could easily have blown a belt on the way home, and been stranded. This is not an old Triumph or Harley that you can limp home on a wing and a prayer. I was lucky!
2. If you have an increasing or annoying vibration, especially at highway speeds, take a close look at the rear sprocket. Evidently any buildup of road debris on the tops of the teeth can cause some vibration. I suspect a non-concentric, warped, or damaged sprocket could do much the same.