OB_Velociraptor
Registered
Installed my APE manual tensioner this morning. I have a shop manual and reasonable mechanical ability but I am not an expert wrench so I thought my experience might be interesting. I started by printing out the very good intructions posted on this site which involved pulling the valve cover and checking the cam timing. As per the manual, in order to totally remove the valve cover from the engine you have to pull the throttle bodies. I chose not to do this. I removed the valve covers just enough to check the exhaust cam timing and have a look at the cam chain links between the two cam sprockets. My cam chain timing seemed fine which was no surprise since my bike is running fine. I also marked the exhaust cam sproket and cam chain alignment with a magic marker. These marks lined up every 4th revolution of the crank I think. I am at work now so I don't remember exactly. That done I removed the automatic tensioner(which extends full out as it is removed so there is no way to know how much it was extended in the motor). As written in the instuctions from this site, I finger tightened the manual tensionser. While finger tightening the tensioner I initially found some minor resistence to turning but this seemed to give way pretty easily then I finally felt I had hit someting solid and it got very hard to turn. I imagine that this was when I started putting tension on the cam chain. I backed off just a little-maybe 1/8th of a turn. I then rechecked the cam timing and everything was the same. I then put things back together enough to get the engine running-valve cover back on,airbox on, etc, and started the motor. I didn't hear any ratcheting noises so I very slowly loosened the tensioner. This got a little tricky for me because you have to know what you are trying to hear. I heard some very faint ratcheting but almost more useful to me was to keep my fingers in the tension bolt and feel what was coming through the bolt. I could loosen the bolt a little and start to feel something kind of hitting the end of the bolt and when I tightened it just a little that went away so that is where I left it.
Any comments??? After I was done I revved the motor in increasing increments and listened for anything strange. I went as high at 9K and everything seemed fine.
I took the opportunity to disassemble and look at the automatic tensioner. Mine seemed fine and was not broken. The design seemed fine. Inside the tensioner is a lightweight spring which is made of fairly fine wire with lots of coils for the purpose of keeping a constant low level of twisting force on the worm gear which forces the tensioner rod out. It doesn't take much twisting force to extend the rod but it takes a lot of force to compress the rod back any amount by pushing on the rod. Just looking at how it is made I am surprised that there have been failures. It seems that there could be four ways that there could be a failure. 1)-The spring could break perhaps from metal fatigue. 2) The worm gear could get dirty and jam causing the rod not to extend-this seems very unlikely. 3) The tensioner could be assembled incorrectly so the spring did not have the proper tension. 4) The engine could develop some strange harmonic vibration that would cause the worm gear to turn against the spring tension. I haven't ridden the bike since going to the manual, but from the way the engine was running in the garage I expect that it will feel no different. My auto tensior was post recall and had three dots. My bike is a 99 model with about 4K miles with probably only 1.5k miles on this tensioner. I don't ride my bike real hard but I have done one track day where I rode the bike very hard. Hope this info helps and I welcome any comments and even flames!
Any comments??? After I was done I revved the motor in increasing increments and listened for anything strange. I went as high at 9K and everything seemed fine.
I took the opportunity to disassemble and look at the automatic tensioner. Mine seemed fine and was not broken. The design seemed fine. Inside the tensioner is a lightweight spring which is made of fairly fine wire with lots of coils for the purpose of keeping a constant low level of twisting force on the worm gear which forces the tensioner rod out. It doesn't take much twisting force to extend the rod but it takes a lot of force to compress the rod back any amount by pushing on the rod. Just looking at how it is made I am surprised that there have been failures. It seems that there could be four ways that there could be a failure. 1)-The spring could break perhaps from metal fatigue. 2) The worm gear could get dirty and jam causing the rod not to extend-this seems very unlikely. 3) The tensioner could be assembled incorrectly so the spring did not have the proper tension. 4) The engine could develop some strange harmonic vibration that would cause the worm gear to turn against the spring tension. I haven't ridden the bike since going to the manual, but from the way the engine was running in the garage I expect that it will feel no different. My auto tensior was post recall and had three dots. My bike is a 99 model with about 4K miles with probably only 1.5k miles on this tensioner. I don't ride my bike real hard but I have done one track day where I rode the bike very hard. Hope this info helps and I welcome any comments and even flames!