You do not "need" the clutch to shift. Motorcycle transmissions for the most part are "dog boxes" not like a synchromesh transmission in your car. Although you can shift synchromesh clutch less also, we wont get into that. Your motorcycle transmission (very simply put) has a peg on the side of the gear that engages with a hole on the gear next to it. When any 2 gears are locked together it produces a different ratio to your rear tire. When you shift from one gear to the next, you pull the peg from the hole in one gear and engage the pegs on the other side of the gear with the hole on the gear of the opposite side. You really need to google how it works but here is my point: To disengage the dog (peg) from the dog hole, you simply reduce torque on the gear (let off on the throttle). When you use the clutch, that's all you are doing, reducing (or eliminating) torque.
When people say you must or should use the clutch, simply do not know how it works period. If you do not believe me you really need to do the research for your self and find out.
That being said, you can cause damage by doing it wrong. If you try to shift while torque is being applied thought the trans, it will round off the dogs (pegs) and this is damage. If the dogs or holes get damaged they have trouble holding on to eachother. If they do not have good hard edges to lock onto eachother, they will separate when torque is applied (will spit into neutral).
Like I said this is all very simplified but hopefully this makes you want to find out how it actualy works. Also on a side note, 95% of the time I up shift my dirt bikes with out the clutch. Been ridding dirt for 20 years with exactly 0 transmission related failures. I do not down shift clutchless. Not because it can't be done, but because it would require more effort to do that way, than just pulling in the clutch. See when you decel, the torque runs from your back tire up through your tranny and into your engine (opposite of acceleration). So if you are under engine breaking, to reduce torque throught the tranny, you would need to blip the throttle, and at the instant make the shift. Who wants to get back on the throttle while trying to slow down? It unsettles the bike. Pulling in the clutch and rev matching while you brake stedily, is for me a much better way of getting set up for the next corner/obstacle.
2005 ZX6R (and it's ugly)
2006 CRF 450
1993 CR 500, the big 2 smoke
I can't spell and neither can my iPhone
Last edited by williams805; 03-10-2012 at 11:37 PM.