Nice to hear from you dj! 
I was wondering when you were gonna chime in on this '08 banter. Thanks for the update. I like the second one. Someone must have some insight on these 110's! 
Keep us up to speed so we hear it here first! 
This is for old time sakes! 
Hoist! 
The other day I was riding downtown and caught my reflection in a storefront window. At first glance my reflection looked just like this little jumping dude
until I had time to focus; pretty much sums up my perspective on the subject of motorcycling.
As long as you are asking, I do have a few speculative thoughts about the late model Twin Cam’s.
Regarding flywheel shift, one thought that I hear kicked around is that this engine’s ability to accelerate in high gear at engine speeds near 1,500 rpm will cause the flywheels to shift. The claim is that torque spikes of 1,300 to 1,500 foot pounds can be measured at the crankpin in 6th gear under low rpm, wide open throttle conditions. I have heard that the torque smoothing recalibration is designed specifically to address this.
The new 6 speed’s primary and overall gearing place a much greater load on the engine’s compensating sprocket which results in the rapid loading and unloading of the assembly at extremely low engine rpm’s; I’ll bet the mechanical stops of this sprocket take quite a pounding under these conditions. ECM recalibration along with the rubber isolated rear wheel sprocket will allow the rider to lug the engine down well below reasonable minimums without breaking engine parts. I never add significant power while in the higher gears below 2,500 rpm; it just doesn’t feel right.
Regarding the Timkin left main bearing; I haven’t seen one of the late model roller bearings fail yet, so this is pure speculation. I’ll bet a can of Diet Coke that failure mode of the big roller bearing is linked directly to flywheel shift. It is my strong sense that the off-axis rotation (wobble) of the sprocket shaft overloads the roller bearing by concentrating the load on the outboard edges of the rollers and races. The Timken bearing by design is better equipped to handle this kind of load. It is my sense that a set of shifted flywheels would eventually loosen the Timken races in the crankcase given enough time. I would be surprised to learn that a straight set of press together flywheels would flex enough to overload the late style left main roller bearing.
As always, these tidbits along with $4.00 will get you a piping hot cup of genuine Starbucks coffee.
djkak
Author
Topic: valve springs (Read 12380 times)