Clutchless shifting?

[Wren]

Just a question.Is this healthy for the bike and if so how do you do it properly?:confused:

[ching_ching]

Hi Wren.

I've had no qualms with the bikes I've owned when shifting clutchless. The gear boxes have stood up to it no probs (I'm talking upshifting here). The only non-japper I owned was a buell firebolt 1200 and it upshifted no probs at all while the jappas with their cassette type close ratio boxes are a breeze. Basically you blip the thrott off momentarily (as per usual as if you were going to use the clutch) then change up quick smart - no dramas. Go on son... geev eet a gaooo!! :Punk:

[Wren]

yeah thanks for that .I have a Triumph Daytona 955i.

[bogan]

I assume you mean preload shifting, you put pressure on the shift lever (upshift this is) the torque being transfered through the gearbox holds it in gear. Blip off the throttle, which removes the torque and thus allows the shift. This type of shifting is quicker, but wears the dogs due to the preloading.

[p.dath]

I' ve been working on the idea that if it feels easy on the 'box then it is ok.

I tend to manual shift 1st to 2nd, and then go clutchless from there. But having said that, even then most of the time I still use the clutch. I ride on the road, and the milliseconds of time that it saves me makes no difference to my riding.

[skidMark]

I'm the same as pdath, clutch first to 2nd.... for the rest of the gears, roll off the throttle to take the load off a bit shift and back on the gas.... just shift as you would with clutch but don't use it, if you are getting a jolt/ graunch practise it until you can get it smooth... i found learning it on downshifts was a bit easier... or practise in the upper gears on the motorway etc, rather than trying to learn it thrashing the bike in the twisties...

it verys when i use the clutch... ask any motorcrosser and they will tell you how they use the clutch not just for changing gears... you can also incorperate this into your riding... but don't try learn it all at once or youll have more than a buggered gearbox to worry about, i do clutch my katana though being an older bike, newer bikes it's not so much of an issue.

[bogan]

...
it verys when i use the clutch... ask any motorcrosser and they will tell you how they use the clutch not just for changing gears... you can also incorperate this into your riding... but don't try learn it all at once or youll have more than a buggered gearbox to worry about, i do clutch my katana though being an older bike, newer bikes it's not so much of an issue.

true, though theres a lot more factors in mx, with all the bumps it basically impossible to preload shift, trying to hang on to it takes so much effort (for me anyways) that using the clutch for shifting results in severe arm pump after 5-10mins (track dependant). Cos i ride a two stroke I often have to clutch it to get back on the pipe, main use for it actually. You dont have the arm pump issue on road bikes, and its apparently nicer on the box to do clutch shifts. Remember the engine has to change revs for every shift, the quicker the shift, the less time all that rotational inertia has to change speed, resulting in higher forces in the box. My observations anyway, at the end of the day; horses for courses :scooter:

[Kickaha]

I assume you mean preload shifting, you put pressure on the shift lever (upshift this is) the torque being transfered through the gearbox holds it in gear. Blip off the throttle, which removes the torque and thus allows the shift. This type of shifting is quicker, but wears the dogs due to the preloading.

You don't need to preload to shift, you roll off the throttle as you change up, do it all the time on the Ducati as it's smoother to change

[YellowDog]

You don't need to preload to shift, you roll off the throttle as you change up, do it all the time on the Ducati as it's smoother to change
Agreed. You can change up and down a great deal faster and more smoothly without the clutch. Just focus on getting the engine speed right.

Ideal for when you have a pillion on the back. Helps reduce the chance of an odd helmet bang.

[discotex]

You don't need to preload to shift, you roll off the throttle as you change up, do it all the time on the Ducati as it's smoother to change

Exactly..... There's no need to preload (and munt your gearbox) to shift without the clutch. You just let off the gas a little like you would when normally changing gears.

The best way to start is to reach for your clutch as if you were going to pull it in but just don't - instead just tap it with your fingers. Do everything else like you normally would.

I only bother at high revs on the track so I don't over-rev. Letting completely off the gas and pulling in the clutch when you're at the throttle stop is rather tricky and time consuming to get right.

[Maki]

No preload + smooth shift and you will have no problems.

I used to shift clutch less all the time when i had a 250. I needed every advantage I could get to keep up with faster folks. I usually use the clutch on my 600...

[Chrislost]

Just a question.Is this healthy for the bike and if so how do you do it properly?:confused:

Get a quickshift kit:Punk:
The bike will blow mean flames whenever you change:eek:
If you have good timing you can hit the rev limiter and the loss of power there will allow you to shift, easy to get wrong tho

[Ooky]

hmmm real bikes have no limiters!:Punk::scooter:

[sinfull]

My scooter dosn't have a second ? Am i doing something wrong ?

[Laxi]

my clutch only gets used at lights:shifty: habit I picked up from riding motox bikes

[skidMark]

Agreed. You can change up and down a great deal faster and more smoothly without the clutch. Just focus on getting the engine speed right.

Ideal for when you have a pillion on the back. Helps reduce the chance of an odd helmet bang.


helps if the pillion is holding the tank... mainly works under braking then, but i'd imagine it would have to be a pretty bad shift otherwise.

[Gremlin]

Wow... I could swear we've covered this before...

oh wait... we have :yawn:
http://www.kiwibiker.co.nz/forums/showthread.php?t=85042&highlight=clutchless
http://www.kiwibiker.co.nz/forums/showthread.php?t=78906&highlight=clutchless
http://www.kiwibiker.co.nz/forums/showthread.php?t=34427&highlight=clutchless+shifting

[wbks]

I'm the same as pdath, clutch first to 2nd.... for the rest of the gears, roll off the throttle to take the load off a bit shift and back on the gas.... just shift as you would with clutch but don't use it, if you are getting a jolt/ graunch practise it until you can get it smooth... i found learning it on downshifts was a bit easier... or practise in the upper gears on the motorway etc, rather than trying to learn it thrashing the bike in the twisties...

it verys when i use the clutch... ask any motorcrosser and they will tell you how they use the clutch not just for changing gears... you can also incorperate this into your riding... but don't try learn it all at once or youll have more than a buggered gearbox to worry about, i do clutch my katana though being an older bike, newer bikes it's not so much of an issue.So you're advising him to learn how to mx style fan the clutch? What a wanker. Do NOT clutchless downshift, Wren


true, though theres a lot more factors in mx, with all the bumps it basically impossible to preload shift, trying to hang on to it takes so much effort (for me anyways) that using the clutch for shifting results in severe arm pump after 5-10mins (track dependant).Maybe you should train or masturbate less, then.:bleh: Generally if you listen to decent riders riding they slip the clutch to change and just hold the throttle open, you don't have time (or money) for balancing the revs to make a nice clutchless upshift

Like discotex, the only reason you would really worry about clutchless shifting is to stop overrev at the track. Have you ever rode really hard to around redline and pulled in the clutch to change? Sounds pretty gay, not to mention revving the shit out of it
Unless your bike's got a slipper clutch I wouldn't clutchless down shift either. That is unless you like momentary lockups at highspeed, but that's what your right foot is for!

[bogan]

Maybe you should train or masturbate less, then.:bleh: Generally if you listen to decent riders riding they slip the clutch to change and just hold the throttle open, you don't have time (or money) for balancing the revs to make a nice clutchless upshift

Probably both, well definetly train more anyway. Who said anything bout matching revs, I just throttle off and bang it through, 2T so bugger all rotating mass/engine braking, know plenty of others who do this on 4Ts as well.



Like discotex, the only reason you would really worry about clutchless shifting is to stop overrev at the track. Have you ever rode really hard to around redline and pulled in the clutch to change? Sounds pretty gay, not to mention revving the shit out of it
yeh, I have noticed that on my roadbike, and thats just a 250 @ 10k, I imagine the effect would be somewhat magnified on bigger bikes at the track.

[Crasherfromwayback]

: Generally if you listen to decent riders riding they slip the clutch to change and just hold the throttle open,

Eh? Like fuck they do!

[Maki]

Generally if you listen to decent riders riding they slip the clutch to change and just hold the throttle open, you don't have time (or money) for balancing the revs to make a nice clutchless upshift



Do that on the 1st to 2nd change on the R6 and you will be left sitting on the road wondering where your bike went...

[wbks]

Do that on the 1st to 2nd change on the R6 and you will be left sitting on the road wondering where your bike went...Sorry if I didn't make it clear, but I was talking about MX riding


Eh? Like fuck they do!Yes they do. Saves rolling off throttle. Did you think I was talking road racing?

[SMOKEU]

The gearbox would wear out a lot quicker if the clutch isn't used to upshift wouldn't it?

[Maki]

The gearbox would wear out a lot quicker if the clutch isn't used to upshift wouldn't it?

Depends on how you do it. Smooth shifts with no preloading should be fine.

[Sidewinder]

well theres only one way, you shift with out using the clutch duh:doh:

[Crasherfromwayback]

Sorry if I didn't make it clear, but I was talking about MX riding

Yes they do. Saves rolling off throttle. Did you think I was talking road racing?

Still don't agree with ya.

[wbks]

Still don't agree with ya.I don't know your background, but from my time in MX every average or better rider just held the throttle open and slipped the clutch each time they tapped the shifter up with their foot.

Look. Arguably a "good rider" and if you can see his clutch fingers in the first 20 seconds or so, and aren't deaf, you can clearly hear it overrev between shifts and see his fingers slip the clutch
http://www.youtube.com/watch?v=lfbFyjddI68

[short-circuit]

For road riding purposes I'll clutch 1st to 2nd and often go clutchless from there up. I back off the throttle slightly when shifting and whack it back open after gear changes. Technically there's nothing to stop you downshift too using this method but I don't really see a need to chop down fast enough to warrant a clutchless downshift

[mossy1200]

My trumpet does zero to a hundy in 30 seconds.Clutchless gear change could save me a second of my life that I could use later.
I use my clutch on the track up shifting aswell.Its done with a different hand from everything else so im not convinced the gearchange takes longer.

[bogan]

Sorry if I didn't make it clear, but I was talking about MX riding

Yes they do. Saves rolling off throttle. Did you think I was talking road racing?

I also disagree, surely its easier to just roll off the throttle than it is to grab the clutch.

[wbks]

I also disagree, surely its easier to just roll off the throttle than it is to grab the clutch. I thought this was going to be an easy concept to understand... Watch the video... At any point besides braking does it sound like his throttle isn't wide open? Seriously... People who disagree: Find ONE video of a pro mx/sx'er in recent years who rolls off the throttle to make a gear change while racing

[bogan]

I thought this was going to be an easy concept to understand... Watch the video... At any point besides braking does it sound like his throttle isn't wide open? Seriously... People who disagree: Find ONE video of a pro mx/sx'er in recent years who rolls off the throttle to make a gear change while racing

Well I couldnt really make out what was going on in that video, so I googled it. One page was pretty helpful, seems you are right, and me and crasher may still be on the beginers shifting technique


I have noticed that a lot of beginning motocross riders often get pretty confused about how to shift gears properly. Everyone seems to have a different opinion and it can be quite difficult to find instructional materials that actually cover this important aspect of motocross technique.

There are two ways that I personally like to shift up gears on a motocross bike and I'm going to attempt to explain them in this short article.

For the first way you don't have to use the clutch. Basically all you need to do is back off the throttle, shift up and then get straight back on the throttle as quick as you can. It's ok to not use the clutch in this situation as the drive is momentarily disengaged.

This way is fine but since you have to back off the throttle, you will lose a bit of momentum and you can't afford to do that in a race.

There is a much more effective way of upshifting that will actually allow you to go much faster and you won't lose any speed.

All you need to do to is get the throttle pinned wide open, pull in the clutch just a tiny bit so that the engine is just about disengaged, shift up then let out the clutch. Do this as quickly as you can and make it one fluid motion. This will allow you to keep the revs high so that when you let the clutch out, the power is there right away. You won't have to wait for the power to dial in again as in the previous method.

Now, a lot of people think you have to use the clutch when downshifting but that isn't the case at all. When you shift down, there isn't anywhere near as much of a strain on the engine so it's not really necessary. In fact, by not using the clutch you are able to use the engines natural resistance to help you slow down (this is called engine braking). Ideally, the only time you should be shifting down is when you are on the brakes. Being on the brakes means that there is even less strain placed on the engine and the combined effect will allow you to slow down a lot more efficiently.

I hope this will help to clear up any confusion you might have about shifting properly on a motocross bike.

from here http://ezinearticles.com/?Motocross-Tips---How-to-Shift-Gears-For-Maximum-Speed&id=2008471

I suppose the clutch technique require a bit more skillful timing, Ill have to try it sometime, though atm on my list of things to improve, shifting isnt really on the urgent side <_<

[Sidewinder]

better off get a quickshifter:whocares:

[Crasherfromwayback]

Well I couldnt really make out what was going on in that video, so I googled it. One page was pretty helpful, seems you are right, and me and crasher may still be on the beginers shifting technique



from here http://ezinearticles.com/?Motocross-Tips---How-to-Shift-Gears-For-Maximum-Speed&id=2008471

I suppose the clutch technique require a bit more skillful timing, Ill have to try it sometime, though atm on my list of things to improve, shifting isnt really on the urgent side <_<

Mate...if you wanna totally fuck your transmission do as they say. Time wasting not using the clutch...frog shit. It takes a split second to crack the throttle off and hook the next gear...and who says drive/revs drop? Total load of shit. Ask Mick Doohan. never even used a speed shifter...and it makes no fucking difference wether you're racing in the dirt or on tar...I know this...done both. Crack the throttle off a split sec...hook the next gear.

[wbks]

Mate...if you wanna totally fuck your transmission do as they say. Time wasting not using the clutch...frog shit. It takes a split second to crack the throttle off and hook the next gear...and who says drive/revs drop? Total load of shit. Ask Mick Doohan. never even used a speed shifter...and it makes no fucking difference wether you're racing in the dirt or on tar...I know this...done both. Crack the throttle off a split sec...hook the next gear.Mick Doohan has fuck all to do with the argument. If you can find a quote from anyone from Daryl Hurley to James Stewart proving me wrong, do it. Totally wreck the trans? Me and everyone I know that races MX has put over 200 hours on single bikes doing this from stock, and besides top end rebuilds and box oil changes they haven't needed to touch it. Are you going to tell me it wears out your tranz oil faster? You really need to try it some time, it will help. And yea it does actually make a difference dirt or tar. When was the last time you fanned the clutch out of corner on a litrebike?

[Crasherfromwayback]

Mick Doohan has fuck all to do with the argument. If you can find a quote from anyone from Daryl Hurley to James Stewart proving me wrong, do it. Totally wreck the trans? Me and everyone I know that races MX has put over 200 hours on single bikes doing this from stock, and besides top end rebuilds and box oil changes they haven't needed to touch it. Are you going to tell me it wears out your tranz oil faster? You really need to try it some time, it will help. And yea it does actually make a difference dirt or tar. When was the last time you fanned the clutch out of corner on a litrebike?

Neither Daryl Hurley or James Stewart are good enough to lick Doohans balls yet. The original question (I belive...without reading it all again) was harm to the trans doing clutchless upshifts? Interupting the power delivery by pulling the clutch but keeping the throttle pinned will send a nasty jolt through the trans every single shift....and it's NO quicker than cracking the throttle off.

WHAT do you think an electronic speed shifter does on a RR bike mate? Interrupt the ign for a mill sec to take the load of the trans so you can keep it pinned and hook the next gear? Bit like cracking the throttle off eh? I've got an RMZ450...if you ever want to see what's quicker in a stright like no worries...we'll have a few side by side race strats to see.

And fan the clutch of a litre bike out of a corner? Whe're not talking fanning clutches out of corners...we all do that on dirtbikes...well different from doing so when changing gears though mate.

[mossy1200]

The threads about sports bikes from a road rider wanting advice.In the name of making things last reduce throttle and use clutch.Reduce the impact of horspower on moving parts to increase life expectancy.Guys that race expect thing to break and explode at some point but im sure every road rider would rather not strip their engine every 2nd year searching for the damage they induced by riding hard to win races.
Its not a race and bikes are fast enough to enjoy without giving them death every time you go riding.Ride it like you want to keep it forever.

You guys riding mx bikes do so on light bikes, on surfaces that allow for wheel spin and you dont try jarring 130hp when you shift gears.

[Wren]

Okay,thanks for the help and advice people.
I have tried what you have said and it does seem smoother on the Mrs, She didnt hit me in the back with her helmet once,at least not by accident:laugh:

[wbks]

Neither Daryl Hurley or James Stewart are good enough to lick Doohans balls yet. The original question (I belive...without reading it all again) was harm to the trans doing clutchless upshifts? Interupting the power delivery by pulling the clutch but keeping the throttle pinned will send a nasty jolt through the trans every single shift....and it's NO quicker than cracking the throttle off.

WHAT do you think an electronic speed shifter does on a RR bike mate? Interrupt the ign for a mill sec to take the load of the trans so you can keep it pinned and hook the next gear? Bit like cracking the throttle off eh? I've got an RMZ450...if you ever want to see what's quicker in a stright like no worries...we'll have a few side by side race strats to see.

And fan the clutch of a litre bike out of a corner? Whe're not talking fanning clutches out of corners...we all do that on dirtbikes...well different from doing so when changing gears though mate.James Stewart is the fastest supercross racer in the world, Doohan used to be the fastest GP rider. My argument was that in MX you flatshift, you said that "dirt or tarmac it's the same deal". I'm sticking to it. If you are really willing to let me on your 08 rmz I'll be more than willing to show you the time saved changing gears, though! You shouldn't though, I might blow up ya tranny!:blink:

[Crasherfromwayback]

James Stewart is the fastest supercross racer in the world, Doohan used to be the fastest GP rider. My argument was that in MX you flatshift, you said that "dirt or tarmac it's the same deal". I'm sticking to it. If you are really willing to let me on your 08 rmz I'll be more than willing to show you the time saved changing gears, though! You shouldn't though, I might blow up ya tranny!:blink:

James Stewart has a fucking long way to go before he can even be mentioned in the same sentence as Mick Doohan. Ricky Charmichael maybe.

We'll have to agree to disagree on this...but you go get yourself a late model 450 to ride...I've got mine and I'm backing myself to dust you off in a drag race. In the dirt or on tar.

[Dave-]

i shiftless up from 1st the whole way, even in town.

I'll clutch for all my down changes though.

[Chrislost]

well theres only one way, you shift with out using the clutch duh:doh:

You should know that using the clutch while wheelieing is looptastic

[Wren]

Whats a quick shifter guys?

[Wren]

And how do I get rid of my L-Plate Rider rating

[bogan]

And how do I get rid of my L-Plate Rider rating

you have to go sit the kb'r test, to ensure you fit in with the crowd, its kinda like a scratchy test, but on a computer. Dont worry if you fail, you can sit it once per day till you pass.

[Wren]

Nevermind I found it

[MSTRS]

Whats a quick shifter guys?
An electronic device to interrupt the power, which means the load on the gears is removed momentarily, allowing you to change gear (with your foot as normal) without using the clutch and without buttoning off the throttle. Becoming common on race bikes. I think...

And how do I get rid of my L-Plate Rider rating

Keep posting. As your count goes up, the user title will change...

[gatch]

You found the kbr exam ??

[Chrislost]

And how do I get rid of my L-Plate Rider rating

talk more then you ride!

[Chrislost]

An electronic device to interrupt the power, which means the load on the gears is removed momentarily, allowing you to change gear (with your foot as normal) without using the clutch and without buttoning off the throttle. Becoming common on race bikes. I think...


Keep posting. As your count goes up, the user title will change...

Apparently illegal in NZ F2?

[Wren]

You found the kbr exam ??
Yep sure did. Shall I tell you where to go?:innocent:

[gatch]

No no, I'm heading there anyway ha.

[Wren]

So did I pass the first test .Do you think I fit in here?

[McDuck]

Hmmm my 400 gos up and down guite happy and smooth. It is not un commen for me to be smother (both up and down) by clutchless. Just seems normal to me?

[gatch]

So did I pass the first test .Do you think I fit in here?

Your certificate will be couriered to your awaiting hands.

Upgrade to the gold scripted parchment version for a nominal fee..

[R1madness]

I love this thread, please give me a call for a quote on your next gearbox rebuild, We are good at them, we do them all the time for people that read these clutchless threads but keep their bike for a while... its amaising how short a time it takes to wear them out with abuse....

[McDuck]

:confused::confused::confused:
I love this thread, please give me a call for a quote on your next gearbox rebuild, We are good at them, we do them all the time for people that read these clutchless threads but keep their bike for a while... its amaising how short a time it takes to wear them out with abuse....

But isnt the average pree crash life of a bike on KB about 8kms so they never make it to a rebuild?:confused:

[grusomhat]

I read something somewhere that seemed to make sense. The clutch is made to be replaced. The transmission is not. (Talking with relativity to easiness)

Have I got that right?

[onearmedbandit]

Ian speaks from his experience of having rebuilt numerous gearboxes from hamfisted riders changing gear without the clutch. I however can honestly say that after 2yrs and 30,000km my gearbox is still fine (from an operational view) after numerous clutchless changes both up and down the box. Still, if it's not done correctly then you'll be on a first name basis with your mechanic.

[gatch]

From a machinist point of view, a clutch is made to gradually apply power to a system, equalising speeds between driving and driven sides of a system, also reducing shock loading on wearing surfaces, it only makes sense that not using your clutch WILL wear out your box faster than without..

[p.dath]

From a machinist point of view, a clutch is made to gradually apply power to a system, equalising speeds between driving and driven sides of a system, also reducing shock loading on wearing surfaces, it only makes sense that not using your clutch WILL wear out your box faster than without..

Ahh, but if the time to wear out the box when not using the clutch is longer than the life of the bike, then it's just a technical point.

Even it it shortened the servicing time from 200k to 100k - that's still a lot of use.

[gatch]

Ahh, but if the time to wear out the box when not using the clutch is longer than the life of the bike, then it's just a technical point.

Even it it shortened the servicing time from 200k to 100k - that's still a lot of use.

Yer fair enough, I wouldn't like to estimate the life of a bike though, I'd rather everything stay in as good a condition as I can for the sake of an extra 1/4 second while shifting gears..

[onearmedbandit]

I must admit that the only real reason I don't use the clutch for every change is purely down to only having one arm. The clutch set up is fine, albeit a new lever/perch and cable will help, but I find that on the track especially it is simply easier to change without the clutch.

[Dropped]

it doesn't matter when i change gear without the clutch it goes perfect.

[onearmedbandit]

From a machinist point of view, a clutch is made to gradually apply power to a system, equalising speeds between driving and driven sides of a system, also reducing shock loading on wearing surfaces, it only makes sense that not using your clutch WILL wear out your box faster than without..

Correct me if I'm wrong, but I'd argue that. Using the clutch reduces the load on the gearbox by disengaging the drive from the box. Having the throttle at the correct point also does the same, granted it doesn't disengage but it does reduce the load. So how can that damage the box? Using either the clutch or throttle application, the bike changes gear as lightly and sweetly as each other method. Opening the throttle after the gear is selected matters nothing, because the gear is already home, in fact no different from opening the throttle from a closed position at any time during the ride.

[bogan]

Correct me if I'm wrong, but I'd argue that. Using the clutch reduces the load on the gearbox by disengaging the drive from the box. Having the throttle at the correct point also does the same, granted it doesn't disengage but it does reduce the load. So how can that damage the box? Using either the clutch or throttle application, the bike changes gear as lightly and sweetly as each other method. Opening the throttle after the gear is selected matters nothing, because the gear is already home, in fact no different from opening the throttle from a closed position at any time during the ride.

ill add an engineerist's point of view, with clutchless shifting, the engine revs (roatitional inertia) changes very quickly, clutched shifting it can change slower. Gearbox must supply this changing force, so there is more force on the box during clutchless shifts. Of course this force could very well be less than it is under full throttle acceleratuion anyways so (as always) my point could be null

[gatch]

Correct me if I'm wrong, but I'd argue that. Using the clutch reduces the load on the gearbox by disengaging the drive from the box. Having the throttle at the correct point also does the same, granted it doesn't disengage but it does reduce the load. So how can that damage the box? Using either the clutch or throttle application, the bike changes gear as lightly and sweetly as each other method. Opening the throttle after the gear is selected matters nothing, because the gear is already home, in fact no different from opening the throttle from a closed position at any time during the ride.

Reducing the load by backing off the throttle is not the same as completing removing load by disengaging the clutch.

When you instantly shift gears something has to change speeds very quickly, with the engines internals being lighter than the rest of the bike, engine rpm will jump or fall. Using the clutch the only part that has to slow down/speed up is the input shaft of the box and gears that sit on it..

Less rotating mass to accelerate/decelerate, less stress on parts.

I think...

[onearmedbandit]

Yeah you're probably right.

[YellowDog]

Well I just stopped doing it after a few scares on the Tiger 1050 forum.

I still believe that if you get the engine speed right and do it smoothly, then it is puttling less stress and wear on the bike however............................
(I could be wrong)

[huff3r]

Well I just stopped doing it after a few scares on the Tiger 1050 forum.

I still believe that if you get the engine speed right and do it smoothly, then it is puttling less stress and wear on the bike however............................
(I could be wrong)

In a synchromesh box it is less stress if done right, because thats how the synchros are designed to work...

In a dog-type box, it could be slightly more damaging, depending wether you got a gap or not, its all guesswork with them

[gatch]

In a synchromesh box it is less stress if done right, because thats how the synchros are designed to work...

In a dog-type box, it could be slightly more damaging, depending wether you got a gap or not, its all guesswork with them

"Most" bike gearboxes are not synchro mesh.

[Juzz976]

I sometimes upshift without clutching and find its really smooth, however I just dont do clutchless downshifts.
I dont believe it causes anymore wear on the gearbox than closing the throttle at high revs.

My opinion is that once you've let off throttle sufficiently for the shift, the reduction in angular velocity required to "mesh" smoothly with the next gear is taken care of by compression and other losses within the reciprocation of your engine.
The inertia of a motorcycle engine is small so the energy difference between initial angular momentum to desired is pretty damn low and is very quickly absorbed by compression and friction.
The output side of the gearbox also has very little inertia and I would hazard a guess this excess energy is spread quickly to the slack in the chain, thus tensioning it and absorbing the residual energy.

I'm not saying that its perfect meshing without wear, because all parts are subject to wear. It's just not all that significant in the overall dynamics of a the type of craft we're dealing with.

anyhows thats my opinion and I ride a bike with 7,000kms on it, they dont last forever and I'm not "going to see how many k's I can get from a bike before something gives out" and "how can I make sure my bike will last 160,000k's" - I think I'd be more inclined to worry about the safety aspects of my bike and how I can enjoy myself more. (of course a gearbox lock up at high speed concerns me but thats a risk we all take.

[Juzz976]

oh yeh last bike I had I did 10,000k's on resulting in 72,000 overall.
I raped the box on that thing and she still runs mint now, it was one of the few things not replaced during my ownership.
I know for a fact the 2 previous owners did too, and most likely the 10 before that too.

Oh yeh did I mention that oil has a slight dampening effect, at high speed energy is absorbed by the reluctance of the fluid being displaced.

[bogan]

I sometimes upshift without clutching and find its really smooth, however I just dont do clutchless downshifts.
I dont believe it causes anymore wear on the gearbox than closing the throttle at high revs.

My opinion is that once you've let off throttle sufficiently for the shift, the reduction in angular velocity required to "mesh" smoothly with the next gear is taken care of by compression and other losses within the reciprocation of your engine.
The inertia of a motorcycle engine is small so the energy difference between initial angular momentum to desired is pretty damn low and is very quickly absorbed by compression and friction.
The output side of the gearbox also has very little inertia and I would hazard a guess this excess energy is spread quickly to the slack in the chain, thus tensioning it and absorbing the residual energy.

I'm not saying that its perfect meshing without wear, because all parts are subject to wear. It's just not all that significant in the overall dynamics of a the type of craft we're dealing with.

anyhows thats my opinion and I ride a bike with 7,000kms on it, they dont last forever and I'm not "going to see how many k's I can get from a bike before something gives out" and "how can I make sure my bike will last 160,000k's" - I think I'd be more inclined to worry about the safety aspects of my bike and how I can enjoy myself more. (of course a gearbox lock up at high speed concerns me but thats a risk we all take.

compression friction etc doesnt really come into play with the timescale we're talking here. Rev you engine in nuetral and see how long it takes to drop a couple of thousand rpm, half a second? clutchless shift times are milliseconds. So virtually all of this angluar momentum has to be absorbed by the driveline, generating large forces in the gearbox.

In saying that though, I havent seen actual figures for engine inertia, shift times, or comparative gearbox torque between clutchless shifting and full throttle acceleration.

[Juzz976]

I also think if the manufacturer didn't want us doin so they would make box's they dont shift nicely without clutching. like a car.

Totally agree with the time factor too and I'd like to investigate further.
my bike drops revs fairly quick, actually faster than the tacho needle can fall. I'll go hook up my ocillioscope later and maybe a vibration sensor and log some graphs for us.

Another consideration is how close your gear ratios are as I think thats a real important factor as I'm not dropping a couple of thousand revs on a shift and the response time of a tacho is pretty slow - most I think would be an analog output from the cdi which has DAC Latency coupled with the dampened effect incorporated into moving coil ammeter/voltmeters subjected to shock and vibration.
I always clutch to second btw. and really I think I can clutch change as fast as non clutch.

And yes to clarify it will be detrimental to the integrity or your gearbox but then who gives a toss. Get a new bike and rape that too. oh yeh and i rekon there ppl out there so shit at doin clutched changes that they put extra stress on their box's anyways.

[gatch]

i rekon there ppl out there so shit at doin clutched changes that they put extra stress on their box's anyways.

Very true, good point.

[Juzz976]

yeh sorry dont have equipment to do the graphs just realised I need to ride the bike to simulate (not really simulate) a shift.

I oscillioscoped the rev fall (from stator pickup) which is fairly quick from 16 down to 15 and as expected a non linear decceleration which reduces as rev fall (something like y = 16,000/aX (a being a fairly high co-efficient of X(time in sec)) is what me graph looked like.

Bikes of course will differ obviously... point tho in gearbox
Inertia I=mr²
m = SFA , r = SFA therfore I = SFA³
and angular momentum = I x angular velocity(say 1570 rad/s (15000rpm))
= SFA³ x 1570
and in conclusion to this wind up we'll say approximatly "not alot"