I used to powershift with the kill switch until once when I mistimed the button and spit the chain out the back. Clutch ever since, up and down.

never unless my clutch cable snaps

Sorry I had to resurect this one: Yeah a constant mesh gearbox is just what it says it is, the teeth in all the gear pairs are always engaged and turning at the correct relative speed. But as it says above

"each gear on one shaft has a matching free-spinning gear on the opposing shaft".

When not transmitting power the free spinning gear and its shaft are travelling at different speeds and they have to be brought to something like the same speed before one of the

"non-free-spinning gears slide over to engage dogs into slots in the free-spinning gear"

Any error and the shaft and whatever else it is connected to will have to under go an almost instant speed adjustment which it, and you, will feel as a jolt. If you are not using the clutch the engine is connected to the shaft and you will experience a large jolt. If you are using the clutch the engine is disconnected and you will only feel a small jolt, if any at all. Clutchless shifts work fine if the time needed for the speeds of the engaging parts to become synchronized just happens to equal the time it takes the shift mechanism to shift gears (this is determined by the shift mechanism, not you!) but it can only work well in a limited range of engine speed and when shifting between certain gears. I've tried it on a Yamaha R6 when racing and I can get better shifts, clutchless between the top 2 or 3 gears at red-line revs where engine speed changes very rapidly and the "gap" between gears is small. I also race a Suzuki GT750 (believe it or not) and it's engine speed changes too slowly for clutchless to work.

Try it, if you get smoother shifts then it works, if you don't: then forget it .

I very much doubt that clutchless shifts work between all gears and at any engine speed on any bike.

Cheers! ~ Gary

I've been able to clutchless shift every cycle I've been on plus dual ratio rear end tractors and dump trucks with like 8 gears to work through. Its sorta like torque values, either you get a sense for it or must depend on interface to function.
Its pretty easy to get a sense of when rpm and loads conditions are ripe to let it just slide into next gear w/o snatch, jerk or any strain, like magic easy. But the other side of this sense is knowing when best to clutch and not take time to match rpm/loads. In public its a personal style choice only, it racing it can make a slight difference where slight differences make all the difference.
Hardest one was big red Indian Chief with hand lever next to tank and dead man foot clutch above the front porch foot rests. Kind a tractor like took some pause for everything to synchronize then level slipped easy no effort for next throttling up to cruise or above.

If you are not careful to keep any toe pressure off shifter while riding it can happen all by itself so beware not to be caught clutchless shifting.

I'm with Ken and Gary on this one.

lcrken wrote: The Commando clutch lasts a long time used normally, and clutchless shifting does wear the dogs on the gears more rapidly. Ken

ggryder wrote: Any error and the shaft and whatever else it is connected to will have to under go an almost instant speed adjustment Cheers! ~ Gary

You have to match the speed of the gears before they will engage really smoothly. Because it's very difficult to match the teeth on gears with 30 or so teeth when spinning incredibly fast we match the 3 or 4 dogs on the sides of the gears into holes or slots on the adjacent gears we shift to. It's these dogs that take the pounding. Have a good look at them next time you take your box apart. They usually show evidence of some of those bad shifts. If you get in the practice of matching your rpm's between gears you can save wear on your clutch too.

Like you Hobot, I too learned to shift on some different vehicles. Here's a shot of my 54 Dodge Power Wagon that I really learned clutch-less shifting on.



It has no synchro, no constant ratio, not even helical cut gears! just straight cut gears with nothing in between yet it shifts like a dream without clutch. You just pull it into neutral, bring the rpm's up or down to match the gear teeth on the gear you want and "offer" that gear to it and it "pulls it in" if you are close on your rpm's. On a machine like a Norton Commando with constant ratio this equvicates to letting off on the throttle just a bit as you shift or bring the revs up when down shifting, no need to hang out in neutral territory in between gears. Clutch-less shifting can give you instant acceleration which is quite exhilarating but I do think it wears the dogs faster.

hobot wrote:If you are not careful to keep any toe pressure off shifter while riding it can happen all by itself so beware not to be caught clutchless shifting.

So right! When all is properly aligned it will pull itself into gear.

RennieK. thanks for shifting reality check and impressive flavorful Dodge in colors and setting that just melts me with the heat, bug bites and thorny scratching tasks it takes ya too. This is the hardest thing for me to not grind teeth on clutchless shifts.

'38 JD LA "Popin Jonnny" idle 240 rpm, max 1800 rpm slow but can grind its tires off with kettle drum thumper sounds. Tranny is custom fitted WWII 'Duce' truck.

There's a good explanation of what's involved in clutchless shifting by Paul Dean in the current (OCT 2011) issue of Cycle World (page 66). He doesn't actually say anything that hasn't already been said in this thread, and he supports both sides of the argument, but somehow it seems more authoritative coming from the pages of CW.

Incidentally I accidentally performed a perfect clutchless downshift recently, so I've got to admit it can be done. I got a bit hurried between turns and did everything I would normally do including blipping the throttle, but I didn't touch the clutch lever. I'm not even going to try to do it again, which makes me a little bit concerned that my spirit of adventure is lacking, but no, if you read Paul Dean's explanation of what's going on inside the gear box it should be apparent that ignoring the clutch makes timing much more critical and will increase the frequency of botched shifts.

I have a book on race car driving technique by err?....some famous French driver who's name escapes me, and he recommends to use the clutch because even though it won't provide any benefits in a single race or even a season, it will over the course of your racing career. Well, you might not be racing but you are probably still interested in avoiding destroying a gearbox in your Commando riding career.

Cheers! ~ Gary