Motorcycle Repair: noise, shifting a motorcycle, rear sprocket

Question
I have a 2001 honda vt750dc spirit. 17000 miles it has a clucking noise. Shift into fisrt clunch shift into secound clunck this is what i'm told normal no problem. Problem is that this noise is present thru all gears, say i'm in 1st and excel clunck, clunck , clunck then 2nd same noise, 3rd, same noise and so on once in 5th past a curtain RPM it's gone. But this noise is not present every time I ride. It comes and goes. It pulls strong no miss, the rear sprocket has been changed to a 39t no mods to motor, does not seem to have any clutch slippage . Front sprocket looks to be good, chain will not stay thight even with as little as 100 miles after adjustment. It is the original chain, Another note is my brother has an 03 750 ace and is starting to hear the same noise only not as bad . His bike has a little over 17000 miles. I bought my bike used with 7000 miles on it and has not been in the shop since. I do oil change regularly  

Answer
Hi Kirt,

Some clunking noise is normal. I would need to hear and feel the noise to accurately diagnose the source.

Read the following information.

Respectfully,
Mark Shively



Motorcycle Transmissions, Care and Feeding... by Marty Rood

There are certain techniques which should be adhered to when shifting a motorcycle transmission and the Valkyrie is no different. If the "dogs" are not quite seated all the way in any particular gear, a motorcycle's transmission will tend to very rapidly find a false neutral and then either grab the gear again or downshift into the next lower gear. This will create a very jerky, noisy condition which usually scares the rider into thinking the
bike is about ready to explode.
This article is to show how to stop this "false neutral" from occurring, but if one finds him/her self in that situation; one should decrease speed to almost stopped with the clutch pulled in and then "stab" it into the next lower gear with a quick, firm stab. Trying to do it slowly and tentatively is terribly destructive to the gears and will potentially break off teeth (cogs) as well as rounding off the corners of the "dogs" (very large cogs which actually do the gear engaging).
The most common reason for finding a false neutral is being tentative with one's shifts. One should not attempt to "feel" the shift from one gear to the next. Shifting should be done in an assertive manner with a quick "stab". Doing it slowly so as to not harm the internal shifting mechanics is one of the hardest, worst things one can do to the transmission's shifting assy. The transmission is designed to take considerable abuse due to the differentials in toe pressures from different riders plus the fact that there are no "synchro's" to "feel" through.
There are very large "teeth" associated with each gear called "dogs" (usually from four to twelve per gear), which actually do the engaging for each gear. The gears themselves are always engaged. Since the dogs are so large, they have flat ends which can come in contact with each other and stop the shifting forks from making a full shift. This is the situation which occurs when finding a "false neutral". The clearances are so tight that very often the trainy will pop in and out of the gear it's attempting to engage.
Tentative, or slowly trying to feel into the next gear, will round off the corners of these dogs and thereby allow a trainy to pop in and out of the gear.  Due to the mechanics of the shifting design; a positive assertive shift
is necessary to fully engage the gear. Don't try to "feel" the way into the next gear as one would do in a car while shifting. This "feel" in "cages" is to allow the synchronous mesh to equalize the shaft speeds of the two gears before engagement. On any motorcycle, including the Valk, the shift should be quick and firm because there are no synchros and the gears are already
engaged.

One way to greatly diminish the shifting "clunk" when going from a lower gear to the next higher gear is to slightly preload the shifter with your toe just before bringing in the clutch lever and then as the clutch lever is squeezed, disengaging the clutch; firmly uplift on the toe to reach and fully engage the next gear. This "trick" almost eliminates the clunky shifts so commonly complained about by newcomers to the Valk's shifting intricacies.
Downshifting smoothly is merely done by practicing getting the engine rpm to match the shaft rpm when the clutch is disengaged just before downshifting and letting the clutch back out in the next lower gear. This can be done so smoothly that a passenger wouldn't notice the downshift at all with practice.
Downshifting in this manner also reduces rear tire wear since most of the wear to one's rear tire is done when downshifting and braking due to the coefficient of friction being compromised during this procedure unless it's done very smoothly. When the coefficient of friction is overcome by engine braking, in combination with rear brake pedal being applied; the tire instantaneously temporarily "locks up". The rider is usually oblivious to the occurrence of the rear tire locking up unless it's extreme because it is so temporary; but it, nevertheless, is quite common. If this is allowed to occur in each downshifted gear every time one comes to a stop; the accumulative effect is a greatly reduced total mileage realized on the rear tire before it's completely worn out.
Since most braking should be accomplished using the front brake (at least 75%); the rear brake should be used very conservatively on a routine basis when downshifting (using the above described technique). The extra mileage realized on the rear tire will save a lot of unnecessary replacement expense.