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View Full Version : Clutchless shifting - bad for your bike?



IdunBrokdItAgin
6th January 2010, 18:23
Just discovered how to do clutchless shifting today while trawling the interweb. Went out tonight and practiced upshifting for a while.

It rocks and talk about smooth acceleration if you get it right!

Anyway, rather than be another thread about a noob (myself) discovering new skills that everyone else is probably already well aware of, my question is:
Does it do anything bad to your bike?

Just wondering if it wears out the transmission faster or the like?

Only asking as I see myself using this trick a lot from now on.

p.dath
6th January 2010, 18:57
Just discovered how to do clutchless shifting today while trawling the interweb. Went out tonight and practiced upshifting for a while.

It rocks and talk about smooth acceleration if you get it right!

Anyway, rather than be another thread about a noob (myself) discovering new skills that everyone else is probably already well aware of, my question is:
Does it do anything bad to your bike?

Just wondering if it wears out the transmission faster or the like?

Only asking as I see myself using this trick a lot from now on.

There is about a million threads on this, covering every spectrum of response.

My personal opinion - it should be fine on any modern sports bike, providing it feels smooth. On the flip side, you're probably only saving yourself 500ms over using the clutch, so is it worth taking the risk?

I tend to do clutchless upshifts from 2nd up about 50% of the time. I like the feel of doing them, so if I'm in the mood ...

CookMySock
6th January 2010, 19:00
I asked the bike shop, and they said clutchless shifts of any sort should be left for when you need them, and not done as matter of habit. It's hard on the gearbox and the clutch tortional damper.

Steve

IdunBrokdItAgin
6th January 2010, 19:02
Forgot to search - apologies.

Felt pretty smooth to me.

Anyway cheers for the response - off to search through the threads now.

But it sounds like it is best left to do for sheer fun rather than a habit.

quickbuck
6th January 2010, 19:29
Forgot to search - apologies.

Felt pretty smooth to me.

Anyway cheers for the response - off to search through the threads now.

But it sounds like it is best left to do for sheer fun rather than a habit.

Don't think "Search" Works yet..... Haven't bothered to try today to find out though.

Personally, I have cluchless shifted all my bikes since I was about 10.... After 28 years I haven't discovered any transmission issues that are out of the norm....
Okay, i was getting a speate of false neutrals on my CBR, but that has gone now that I have fitted a cush drive out of another bike.... Might be coincidence... BUT the condition of your drive train can have a huge effect on your gearbox... Also the position of your shift leaver, and bell cranks.

There is a temptation to Pre-Load the gear leaver. Apparently this should be refrained from, as the shift forks wear out prematurely.

Hope this helps.

Daffyd
6th January 2010, 19:32
I tried it a few times but it slipped out of gear once or twice so I gave it up.

vifferman
6th January 2010, 19:52
It's hard on the gearbox and the clutch tortional damper.

WTF is a 'tortional damper'? :confused:
I know what a tort is (legal, or patisserie), and I know what torsion is, but I have no idea what part of my bike is a tortional damper.
A legal damp squib?
A soggy lump of pastry dough?

Mebbe it's some strange Korean delicacy.... :blink:

IdunBrokdItAgin
6th January 2010, 19:59
Okay search function is working again.

Had a good read and the general consensus is that clutchless upshifting seems to be fine but pre-loading your gear lever may cause problems over time.

Gutted as pre-loading the gear lever was what I was doing and it was silky smooth. They should make gear boxes that can handle pre-loading.

I may try and practice some more and upshift without pre-loading but I reckon it will take a bit longer to get it right.

IdunBrokdItAgin
6th January 2010, 20:00
duplicated post

quickbuck
6th January 2010, 20:13
Okay search function is working again.

Had a good read and the general consensus is that clutchless upshifting seems to be fine but pre-loading your gear lever may cause problems over time.

Gutted as pre-loading the gear lever was what I was doing and it was silky smooth. They should make gear boxes that can handle pre-loading.

I may try and practice some more and upshift without pre-loading but I reckon it will take a bit longer to get it right.
Cheers for testing the search function for me.....

Yup, it is a bit of a shame you can't prelaod... However if you make the bits that wear because of it stronger you will only wreck more expencive parts... and the shift forks will be a bit heavy in any case.

The good news is that according to the workshop manual for my bike, it isn't actually too hard to replace them ;)
Can't speak for the cost though, as i haven't had to go there.....

You will get used to upshifting without preloading if you practice... Does save your left hand for just the down shifts too ;)

CookMySock
7th January 2010, 06:31
WTF is a 'tortional damper'? :confused:It's the springs in the back of the clutch basket. Its there because at certain rpms there are quite large harmonics set up in the engine and gearbox, and basically its a hundred times cheaper to allow them to flex something else, er, flexible, rather than engineer them out.

http://en.wikipedia.org/wiki/Torsional_vibration

Steve

IdunBrokdItAgin
7th January 2010, 08:49
Cheers for testing the search function for me.....

Yup, it is a bit of a shame you can't prelaod... However if you make the bits that wear because of it stronger you will only wreck more expencive parts... and the shift forks will be a bit heavy in any case.

The good news is that according to the workshop manual for my bike, it isn't actually too hard to replace them ;)
Can't speak for the cost though, as i haven't had to go there.....

You will get used to upshifting without preloading if you practice... Does save your left hand for just the down shifts too ;)

Had a few goes at clutchless upshifting without pre-loading this morning and it is actually easier than I thought. All seems to be a matter of knowing how much to roll off the throttle before upshifting and then it's all about timing your wrist and foot movements together (pre-loading just avoided the need to time your wrist and foot movements together).

Missed a couple of times but didn't hear any painfull noises. Just rolled on the throttle again and then slightly rolled off to try all over again and it was all good. Tis what practicing is all about after all.

I think I'll leave pre-loading to the serious racers, who probably expect to re-condition their gear boxes regularily.

I even had a go at clutchless downshifting, just to see if I could do it. Worked fine but I won't be using this going forward as there is little need to use it, unless I lose a clutch lever.

Cheers to everyone for all your help.

Biggles08
8th January 2010, 07:02
On the flip side, you're probably only saving yourself 500ms over using the clutch, so is it worth taking the risk?

In a race...ummmm,,,yep! ;-P I never use my clutch for upshifting....ever...but then hey, I've already fucked one gearbox on my ZX6R so who knows :-).

Personally I see no problems at all with upshifting without the clutch if you can 'blip off' the throttle correctly to produce a smooth change...after all, that's all a quick shifter is doing. :shifty: <----Shifty eyes....see what I did there! eh hehe

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Wheeliemonsta
9th January 2010, 14:42
Gidday All,
Modern motorcycles have a sequential gearbox meaning there are no synchro or baulk rings incorperated in there design - shifting without the clutch will not cause damage to this type of gearbox, you do run the risk of accelerated wear to selector forks by so called "Preloading" the lever which is absolutely unecessary to do... The little trick to clutchless shifting is to match engine speed & road speed before attempting to shift thus reducing load on the gearbox

Give it a lash - low road speeds & low engine speeds will result in butter smooth shifts

Shifting at higher engine speeds requires a bit more practice to perfect the technique but it's not difficult if you have at least a modicum of mechanical sympathy...

Cheers

:rockon:

Pixie
9th January 2010, 17:27
WTF is a 'tortional damper'? :confused:
I know what a tort is (legal, or patisserie), and I know what torsion is, but I have no idea what part of my bike is a tortional damper.
A legal damp squib?
A soggy lump of pastry dough?

Mebbe it's some strange Korean delicacy.... :blink:

It's an Australian cake,similar to a Tort but cooked on a camp fire:
Definition: Damper is a simple, yeastless bread often cooked over a campfire in a pot or moulded to a stick.

kwaka_crasher
21st January 2010, 14:59
Modern motorcycles have a sequential gearbox meaning there are no synchro or baulk rings incorperated in there design:

That's not what sequential means. Sequential means the order of the gears never changes i.e. you can't go to 3rd from 1st without pasing through 2nd. What is of interest in the context of clutchless shifting is the fact they're constant mesh gearboxes with drive dogs.

While excessinve and prolonged preloading will indeed prematurely wear shift forks, this wear will not be excessively accelerated if you just lightly preload the lever to take up the freeplay on the drum mechanism prior to backing off the throttle to effect the change.

The Pink Panther
25th April 2010, 18:15
i gather if your wining and your race team has no probs with gearbox rebuilds.

Maha
22nd February 2013, 14:29
There is about a million threads on this, covering every spectrum of response.



No theres not, thereis four, I have checked properly by using the seach function, hence the the dredge...:bleh:
Anyway....I clutchless downshift from top to at least 3rd.....never clutchless upshift, didn't realize you could to be honest?
I don't preload the shifter either, its a matter of fact movement...coupled with rolling off the throttle until gear is engagaed....happens all very quickly.
So what is the general consenus on this subject?..


My Bike My Rules!

bogan
22nd February 2013, 14:35
What are the other 3 then? I recall some good info (fuck knows what it was now though) in one I've posted in...

Maha
22nd February 2013, 14:38
What are the other 3 then? I recall some good info (fuck knows what it was now though) in one I've posted in...

here....this is what search function brings up http://www.kiwibiker.co.nz/forums/search.php?searchid=7243618

bogan
22nd February 2013, 14:46
here....this is what seach function brings up http://www.kiwibiker.co.nz/forums/search.php?searchid=7243618

Hmmm, search links don't appear to transfer over, all the ones I could find were old and didn't deal so much with downshifts anyway, just start a new thread! :msn-wink:

p.dath
22nd February 2013, 14:52
No theres not, thereis four, I have checked properly by using the seach function, hence the the dredge...:bleh:
Anyway....I clutchless downshift from top to at least 3rd.....never clutchless upshift, didn't realize you could to be honest?
I don't preload the shifter either, its a matter of fact movement...coupled with rolling off the throttle until gear is engagaed....happens all very quickly.
So what is the general consenus on this subject?..


Beyond my mechanical capabilities, but the way it has been explained to me is that when shifting down you create a load on the dog gears, and the harder the shift down the greater the load. So I try to be nice shifting down and use the clutch and a blip (the closer the speed of the two on the down shift the less load). Less load should mean less wear on the dog gears.

The other way, shifting up, is not such of a drama, as the relative speed of the two is the same. So no clutch needed. Just, as you say, a momentary reduction in RPM to allow the dog gear to slip in.

p.dath
22nd February 2013, 14:54
Funnily enough, I just found one of my old threads on a very related subject:
http://www.kiwibiker.co.nz/forums/showthread.php/120234-Blipping-tell-me-why-I-am-wrong

Reckless
22nd February 2013, 15:11
I ran karts for many years with Kawasaki, Cadgiva and YZ engines with no clutch basket in whatsoever. The first thing we did to increase power was remove the clutch basket (except for the gear on the back). We used a dog gear disengage for road racing. Never blew a gearbox and Karts make thousands of shifts.

Pre Loading the lever will cause excessive wear and un-necessary.

On the road bike there's not much need but somtimes I do.
On the MX bike I do it 80% of the time both ways up and down.

The trick to clutchless shifting to be "off throttle", even if its only for an instant when you shift. Ie no load on the gears! This is essentual, Its about timing. Its not hard do it right and you wont stuff your box.

Just my 2c ????

bogan
22nd February 2013, 15:18
The other way, shifting up, is not such of a drama, as the relative speed of the two is the same. So no clutch needed. Just, as you say, a momentary reduction in RPM to allow the dog gear to slip in.

The relative speeds are fixed either way though, as are the gear ratios...

In both cases its just matching the engine speed to wheel speed; the bigger the rpm difference, the higher the engine inertia, the greater the engine torque output, and the quicker the shift, all leads to higher forces on the gearbox components. How you shift determines what parts of components see the bulk of this force.

With downshift the engine characteristics is more of a factor than for upshifts. Upshifting you'll get less torque, which is fairly proportional to the gear ratio increase, but downshifting you get a lot more engine braking torque both due to the gear ratio change, and the much higher engine braking torque for higher revs. Another concern for me is the chain, I have to run a lot of slack and a roller, bashing it down is going to bounce that chain around and wear the roller out a lot quicker. Obviously correct throttle control could get engine braking really linear through the change, but its a lot trickier than for upshifts.

ducatilover
22nd February 2013, 15:26
Bogan, does your bros lock up a shit load off the gas in the wet? Mine would in anything under 4th :facepalm: and 3rd in the dry would get snaky unless you feather the clutch.

onearmedbandit
22nd February 2013, 16:49
Clutchless up and down here, 75% of the time. Gearbox has in my time done 40,000km and doesn't miss a beat (or a gear).

tri boy
22nd February 2013, 18:42
Pointless on the road.
Helpful in racing.

A real challenge is shifting a crash box A7 through town when your loaded to the back teeth with double brown, and no lights, and license, and wof, and no clue............

pete-blen
23rd February 2013, 12:14
I have clutchless shifted all my dirt bikes maybe 50% of the time for over 30 years..
Never had a dead gear box yet..
Have noticed Honda's like it more than the others... 2 strokes seem to un-load
the gear train quicker than 4 strokes when closeing the throttle...
When I was road raceing we use to hold the throttle full open.. clutch & shift..
Throttle never left the stop when up shifting... I did have quite a collection of
worn kawasaki & yamaha clutch plates..:rolleyes: