i used to upshift often without the clutch but, I kept hearing mixed debate on whether you should or should not so I started using the clutch again
One way isn't inherently
better than the other, for for the sake of longevity. All manual transmissions are basically the same in cars truck and motorcycles, with a main shaft and cluster gears. the only difference i how the shifter is actuated and how the gears engage. Motorcycle transmissions don't have syncros like the vast majority of car transmissions. Heavy trucks of the early days used dog engagement transmissions which are very similar to our transmissions. Dog engagement is usually reserved for higher HP/RPM cars (after 7000 or so RPM syncros don't work so well at matching speeds in the transmission so you can't shift as fast) and almost always the track. This is one reason there is no syncros in our transmission, the other is that a shift pattern would be a PITA, so a sequential shifter is uses, our happens to be loaded with a strong detent, where if you push it slow it will move quite a bit before the shifter snaps to the next gear. This keeps you from accidentally shifting because of the spring pressure as well as the amount of movement needed to get to the next gear, as well as keep shift speed under control (you can't change how fast the trans shifts by varying your movement of the shifter) so that its one less thing to design the trans around.
This is where the dogs come into play; when you are cruising around,when shifting without the clutch, you have instant feedback about how your speeds were matched inside the transmission with your timing by how much the bike lurches. If you did it smoothly, where you didn't really feel anything, you just noticed a drop in revs. You will notice that there was no transmission noise (
THWACK!) during a smooth clutchless upshift. With no jolt and no thawack, your transmission dogs hardly had any loading at all when they engaged.
With the clutch, it adds another step to "shift" smoothly. I prefer to think of strictly using the shifter for shifting, if using the clutch you are "changing gears" and one of the operations is shifting. Anyway to be smooth, you are shifting the transmission early so that it is all the same speed wit the rear tire so you don't have the quick acceleration or deceleration when you let out the clutch. If it was smooth, then the gears were changed early and that is where the thwack comes from, the engine is still spinning a little faster than the transmission and they instantly match speeds with the dogs.
Now to the detent in the shifter, this was done so that a weak shift still send the next gears snapping together during clutchless upshifts while racing around at high throttle/RPM. This is the essence of this transmission, racing. Its a track refugee, and it was built to go as fast as possible, and that means not using a clutch on upshifts. Now, doing so is way rougher on the transmission than either using the clutch while cruising around. Frankly I feel that is is irrelevant, but also that a good clutchless shift is easier on the dogs in the long run (tens of thousands of miles, versus a race season or two) but again, the trans is made for much more serious abuse that debating the use of the clutch in regards to hurting the transmission is kind of a moot point. If you want to baby your transmission, than use your clutch on upshifts when you are using 100% throttle, then you at least have the engine rotating mass separated from the transmission, and it only has to deal with the mass inside the trans case when instantly matching rotational velocities. Again, this is what the bike was made for, so doing it once in a while will have no effect on longevity, doing it constantly, then you end up on the race bike maintenance schedule, because you are racing around everywhere
