Strange Noise - Help

I get that clunk when i change gears from 1-2 and 2-1, its from the gear box from what i know.. however they say its normal for the bike.. i dont really like that sound.. so im yet still to find the issue.. hopefully some1 have some ideas on this.

 

I use to get this noise( clunk) when i first started riding my Fzr i when shifrteing from first to second, But i dont get it anymore after reading up a review on gear shifting. I was doing an improper shift which caused the gear box to clunk. But after allota practice it stopped.

How i confirmed this was letting my brother ride the bike and when he shift from first to sencond the gear box made the clunking noise.

Same thing happen when i let my cousin ride the bike ( he thinks he can ride but he can't <!-- s:rofl: --><img src="{SMILIES_PATH}/icon_razz.gif" alt=":rofl:" title="Rofl" /><!-- s:rofl: --> ) I heard 2nd CLUNK 3rd CLUNK 4thCLUNK in all the gears man i flet like to <!-- s:sniper: --><img src="{SMILIES_PATH}/icon_snipersmilie.gif" alt=":sniper:" title="Sniper" /><!-- s:sniper: --> shoot him a off the bike. ( my bike has on its original silincer)


So just practice shifting. I hope this helps

 

Hey Sinoz and Dean Here is the post i was talking about I hope you guys read it because it is really helpful, since the fzr's have a very clunky box i advice you guys to read.

Its long lol.

Borrowed from
<!-- w --><a class="postlink" href="http://www.perthextreme.com">www.perthextreme.com</a><!-- w -->

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Motorcycle Transmission Basics 101

by Don Kuhlman

To clutch or not to clutch?

Actually, in the case of shifting your motorcycle’s transmission, that should be "de-clutch" or to disengage the clutch between gear changes. As with such controversies as oil, tires, helmet use and other deeply religious aspects of motorcycle ownership, I leave these decisions up to the reader. Instead, I’ll try to give a little insight into how your motorcycle’s gearbox operates. Then you, as the informed consumer, can decide what’s best for your application.


The typical modern motorcycle gearbox or transmission is a "constant mesh" design. The name comes from the fact that all of the gears in the transmission are in constant engagement with one another. This differs from some older designs where the gears slide back and forth on shafts, engaging one another one pair at a time. The gears are arranged so that you have a drive gear, coupled to the engine, and a driven gear coupled to the rear wheel. They are arranged on shafts, the drive gear on the mainshaft and the driven gear on the countershaft. In most cases, the mainshaft is driven directly by the clutch, which in turn has one set of plates connected to the engine and the other set connected to the mainshaft. Most clutches are driven off the engine’s crankshaft by a gearset as well. They may use direct gears or a chain or belt drive. This is called the primary drive.

The countershaft drives the transmission’s output device, typically a U-joint in the case of shaft drive, or a countershaft sprocket if it’s chain or belt drive. This is called the secondary drive.


One of the gears in a pair of gearsets, will be coupled to its shaft, main or counter, at all times. The other gear in the pair will rotate or spin freely on its shaft on bearings. In between the free rotating gears and splined to the main or counter shaft, are the engagement dogs, or at least half of them. The other half is built into the face of the gears themselves. Each free-spinning gear is then coupled to its shaft by the engagement dog. The engagement dogs are typically one of a few designs, but all of them work basically the same way. The first use multiple fingers and corresponding holes, typically in the gear itself. Others have fingers built into the gear and the corresponding holes in the engagement dog. The Valkyrie’s transmission is built this way. Another type is a blade and slot design. There will be a pair of blades, looking much like common screwdriver tips, on the engagement dog and a set of corresponding slots in the gear. Usually there will be twice as many holes or slots as there are fingers or blades. This is done to aid engagement speed as the dogs and gearsets only have to turn half as far to engage. Older Gold Wing transmissions use the blade and slot arrangement for example. They can be slower shifting than the finger type engagement dogs, but provide a bit more torque handling capability for a given size dog and gearset.

To move the engagement dogs back and forth along the countershaft, they have a slot cut perpendicular to the shaft into which a shift fork fits. In turn, the shift forks are moved by the shift drum that is rotated by a selector mechanism, typically a ramp and pawl design. The shift drum is designed to select only one gear pair and engagement dog at a time. Because of the different ratios, if two or more gear pairs are selected at the same time, the transmission will be locked and unable to turn.

Now here’s a hint for you troubleshooter types: If your engine runs OK but stalls out when you start to engage the clutch, and the bike won’t roll freely, you’ve just found your problem. Your transmission is locked and probably engaging more than one gear pair at a time.

Most 5 and 6 speed transmissions use 3 shift forks. On a typical 5 speed, there will be 1st and neutral, 2nd and 3rd, and then 4th and 5th. Because the engagement dogs have to sit between gear pairs, you can also get false neutrals. Notice that neutral itself is considered a valid gear range in the transmission. Starting out in neutral, the rider disengages the clutch and presses down on the shift lever. This moves the selector to engage the 1st ratio gear pair by sliding the shift fork on that engagement dog into the side of the driven gear on the counter or main shaft. Letting the clutch out (engaging it) couples the engine’s output through the transmission and on to the rear wheel. As speed picks up, the rider rolls off the throttle, disengages the clutch and lifts up on the shift lever. The transmission selector slides the 1st gear engagement dog back to a neutral state and then engages the 2nd gear ratio pair. The clutch is engaged again, the throttle opened and acceleration resumes. The same mechanism applies for each higher gear ratio and then the reverse order on shifting back down through the gears. This is basically how your transmission was designed to operate.

A note here for historians and technoids: A typical modern motorcycle (and some racing cars) transmission has what’s called a "sequential" shifting arrangement. This means that each gear ratio from lowest to highest and back again has to be selected before the next desired ratio can be obtained. Contrast this with your typical car or truck where any gear ratio in the pattern can be directly obtained. In other words, with the latter you can shift directly from 1st to 4th and skip 2nd and 3rd along the way. Not on a motorcycle, as it’s one at a time up and down. There is another type of transmission gear selector not commonly seen anymore called a "preselector." This is where you shift to the next desired ratio in advance, but don’t actually engage it until a declutching action takes place. (Also see preloading towards the end of the article)

Now, there are three states (four if you include being stopped) in your drivetrain that we need to discuss. They are acceleration where the engine is turning the rear wheel; deceleration where the rear wheel is turning against the engine; and a neutral condition between the first two that we’ll call "coasting" for lack of a better term. During acceleration or deceleration, torque is being applied through the transmission. In turn, this applies a load against the shafts, engaged gearsets, engaged dogs, the clutch, and the primary and final drives. Any effort to shift the transmission when the motorcycle is in one of these two states will impart moving thrust and shear forces against the parts in question. If the load is light, it’s still possible to change gears but it also causes some wear. Under a heavier load such as hard acceleration it may or may not be possible and any gear changes run the risk of damaging parts.

So how do dragracers shift gears under a full throttle load?

Actually, they don’t. For a time, even a very brief one, the transmission is in a coasting condition where little to no torque is being transmitted through it. There are several ways to accomplish this little trick. The first, most obvious and most commonly used method is to disengage the clutch. This decouples the engine to the transmission which is then left free spinning from whatever drive is coming through the countershaft from the rear wheel. We can then upshift or downshift with relative ease. If we pick too low a gear ratio for the road speed we’re at, the transmission will start overspeeding and apply some torque as well, but it’s next to nothing compared to what we’ll experience when we let out the clutch!

Screech! Chirp! Skid! Hop, hop, hop!!! Ooooppss…

In other words, it’s best not to shift into low at 60 mph and let out the clutch!

The next way to shift gears is to simply roll off the throttle so that the motorcycle is neither accelerating nor decelerating momentarily; it’s coasting! All of you dirtbike riders and others who have shifted a lot without using the clutch know you momentarily roll the throttle off on an upshift, select the next gear and roll it back on. If the bike is decelerating, we have to roll the throttle on a bit, again to achieve the coasting state, and then make our shift. If it’s a downshift, we should give the engine a little throttle right before the next gear engages whether we’re using the clutch or not to smoothly match road speed to engine speed. It sure helps cut down on those embarrassing oops.

So how does an electric shifter work? Simple really. As you start to push on the shift lever, it engages a microswitch that momentarily kills the ignition. Add an air ram, storage bottle and control switch and you now have an air shifter where you just hit a button on the handlebars under full throttle and it’s instant upshift. They’re real popular with the dragracers who may not be able to get their foot to the shifter right away.

Now, as with so much else in life, timing is everything. Using the clutch ensures the most timing tolerance (i.e. the most time you have to make a smooth shift) and the latter airshifter example is the most critical. This is where everything has to be set up perfectly. In between, we have the rider who likes to shift without the clutch. Some have mastered the timing of having no load on the transmission and perfectly matching the engine speed to the road speed by chopping and blipping the throttle at appropriate times. It should also be observed that the timing is both longer and more critical for changes between the lower gears, and quicker and less critical for the higher ranges. Weird, huh. There are lots of reasons as to why this is but we don’t need to go into them here.

So, what happens when we shift poorly? Parts get worn or worse. The first ones to suffer are usually the engagement dogs and the shift forks. It can also include the counter or main shaft splines and shift selector. Why does the transmission start jumping out of gear? Typically it’s a bent or worn shift fork, or, it can also be worn engagement dogs. This is where the fingers or blades are worn on the ends from improper shifting. Once they get rounded off enough, they don’t fit properly in the corresponding slots or holes in the gear and the transmitting of torque will force them apart. Hence the transmission pops out of gear. It may be acceleration or deceleration or both depending on which side the parts are worn or damaged.

Another technical tidbit: Most dragracing only transmissions have the engagement dogs undercut so that acceleration torque actually pulls them together helping complete the shift. The problem with this is if it is more than 2 to 3 degrees, the transmission will pop back out of gear under deceleration forces. So, a dragracer stages in 1st gear, hits their air shifter button on all the upshifts never releasing the throttle and then pulls in the clutch and coasts to a stop at the end of the run. Letting off the throttle and feeding deceleration forces through this type of transmission will damage or destroy it.

So, pulling in the clutch every time means I won’t damage my transmission, right?

No, not really. Sloppy shifting is still sloppy shifting and will cause extra parts wear whether you use the clutch or not. Obviously, disengaging the clutch will help lighten the load considerably, but it won’t eliminate it entirely. Usual examples of sloppy or poorly executed shifts include shifting too fast, but believe it or not, shifting too slow can be just as bad or worse. Also, coming to a complete stop and then trying to get the bike in a lower gear is not good for the transmission as well as using heavy deceleration (engine braking) at every stop.

If you want a graphic demonstration of some bad shifting, simply pull the clutch in, shift to neutral and then coast for a couple of seconds with the throttle shut off before upshifting or downshifting. Notice how much stiffer the shift lever feels, how slow the transmission is to shift and how clunky it sounds. It might even make a grinding noise as the dogs fight to engage. One example here should be enough, OK? The reason is the two transmission shafts, main and counter, are now way out of synchronization with one another. The countershaft is still being driven by the rear wheel while the mainshaft is being spun by the engine, but only at idle rpm. Slow, lazy shifts can have somewhat the same effect although obviously not as pronounced.

So have you figured out why your bike clunks when going into first gear from neutral while stopped? Yep, the countershaft is stopped while the mainshaft is being spun by the engine. Your oil-bath clutch has some drag, especially when the engine is cold and doesn’t disengage all the way.

Back to our old friend timing again. Ideally, we want our shifts to be timed, along with the proper change in engine speed, so that everything is spinning at approximately the same speed with the engagement dogs meshing smoothly and softly with the gears. No torque will be applied through the transmission until the next shift is completed and everything is fully engaged.

The true pro will also have the engine speed properly matched to road speed for the next gear. If it’s an upshift, the engine rpm will be lower and for a downshift, it needs to come up higher. And this is true between shifts whether or not you actually disengage the clutch or not. Ever hear a roadracer blipping the throttle as they brake into a turn. They’re downshifting furiously, but they’re not necessarily using engine braking. On a two-stroke there isn’t much engine braking available to begin with, and most roadracers have little to no weight on the rear tire under heavy braking. No, what they’re doing as they come down through the gears is using a little clutch drag that’s available even with the lever pulled in and matching speeds of the mainshaft and countershaft for the next gear pair selected. And all this time you thought they did it just to sound cool!

So, do you need the clutch to shift? How about some rules of thumb first. The lighter the bike, the less traction at the wheels (i.e. dirt), the lighter the engine flywheel effect, then the less you need the clutch. Clutchless upshifts are normally much easier to perform than clutchless downshifts. At the other extreme, we have a big, heavy cruiser with a lot of weight and traction, a slow revving engine with lots of flywheel effect, and a big clunky transmission to handle all the extra torque placed through it. Yeah, you can shift it without the clutch, but you’d better be good and know what you’re doing. I’ve seen transmissions damaged in a few hundred miles and others that didn’t start showing signs of abuse for several thousand miles. I can tell you this, even yours truly, let alone any competent shop mechanic, can tell how you shift by just looking at your transmission’s internals. You’re not fooling anyone when you tell them how you "baby" your bike when the evidence points to the contrary. Taken to severe extremes, it also voids your warranty.

So, you’ve got a big, torque laden cruiser and you want it to snick through the gears like your old 125cc dirt bike or your buddy’s 600cc sport bike. Guess what, it ain’t gonna happen amigo. But you can make it as good as it is going to get if you’ll try a few things. The first of these may seem obvious but I see a lot of people forgetting to do it on a regular basis. That is, use a firm, full motion on the shift lever. Although most shift selector mechanisms use an over-center design where the spring-loaded ramp and pawls will try to complete the shift on their own, they’re not always successful. A lazy, half-hearted prod on the shift lever can lead to only a partial engagement of the dogs. This will prematurely wear the dogs, put all the torque through only a part of the load bearing portion of the engagement dogs and will lead to the transmission popping back out of gear.

To aid in the quest of full engagement, make sure your shift lever is adjusted so that you can easily get full travel for both up and down shifts. Everyone has different foot sizes, wears different kinds of shoes or boots and sits on the motorcycle differently. Adjust the lever so that it fits you. Also, make sure it doesn’t hit any engine parts or bodywork that will limit its travel as well. Have a friend check your lever adjustment and travel for you while you sit on the bike in a normal manner. You may need to lower or raise it some. And you want to make sure your foot isn’t resting against the lever except during a shifting operation.

Next, complete shifts quickly and deliberately. I’m not talking about "speed-shifting" here, but in addition to half-hearted stabs at the shift lever, the other trait of a lazy shifter is to delay shifting too long or to take too long in moving the lever. This isn’t a double-clutching, 18-wheeler truck transmission where all shifts stop off at neutral between gears. With the exception of the real neutral, usually between 1st and 2nd gears, your motorcycle’s transmission wants to be in one gear or another. In other words, it doesn’t want to spend a lot of time between gears. What happens is the speed of the main and counter shafts gets out of synch and this leads to a lot of unnecessary extra wear and grinding of the engagement dogs. Remember our example above of pulling in the clutch and delaying the shift for a time?

Conversely, excessive pressure on the shift lever and trying to shift the transmission too fast causes wear and tear of its own. Now the rider is pushing mightily on the lever trying to slam the next gear home. This puts excessive pressure against the shift selector mechanism and quickly wears or damages the shift forks. Taken to extremes, it bends the shift forks and we’re back to the transmission popping out of gear again. It can also mean the transmission is made to start transmitting torque before it’s fully engaged. Here, we’ll see chipped fingers or blades on the engagement dogs and possibly damaged splines on the countershaft. The most brutal shift is the full-throttle, clutchless upshift. It may be worth the extra expense to a dragracer looking to cut a few hundredths of a second off their elapsed time, but for the rest of us, we should shut the throttle off and shift normally.

So, to use the clutch or not. The interesting thing here is this isn’t a strict yes or no type question. You can use the clutch to varying degrees. First, make sure your clutch is working properly. If it’s a cable type, make sure it’s adjusted per the manufacturer’s instructions. If it is hydraulically operated, make sure everything is operating normally and that the system is filled properly with good, fresh fluid. If the clutch seems to drag or not fully disengage once the bike is fully warmed up, try bleeding the system.

Next, when coming to a stop or when engaging the gears from a stop, make sure the clutch lever is fully depressed. And don’t ride the clutch at stoplights and the like. Keep it fully depressed or shift to neutral and let it out all the way. Holding the bike on a hill with the clutch simply heats up the clutch plates, usually making them grabby. Use the front brake to hold the bike until you’re ready to roll again.

Now, experiment with varying degrees of clutch disengagement as you shift up and down through the gears. Personally, I like to use two fingers on most bikes and pull the clutch in about a third of the way for upshifts and about half way for downshifts on a big cruiser like the Valkyrie. On a sportbike with a close ratio transmission I find just a slight pressure release for upshifts and a quarter to a third for downshifts if I’m using engine braking between the gears. If I’m coming up on an especially slow corner and will be quickly executing several downshifts while braking, I may simply pull the lever all the way in and blip the throttle lightly as I work my way down through the gears. In this case I’m not using the engine braking but simply matching up my engine rpm, road speed and gearbox selection for when I reengage the clutch and hit the upcoming curve. To blip the throttle while braking, use your thumb to gently roll the throttle on and off. It takes a bit of practice at first to be smooth and not interfere with your control of the front brakes.

You can also experiment with shifting without the clutch. If nothing else, it provides you a way to get home if your clutch cable breaks or your hydraulic system fails and you can’t get the clutch to disengage. (To start off from a dead stop with the clutch engaged requires starting the bike while it is in first gear so you may have to overcome a starter interlock switch. And push off with your legs as you hit the starter button to help the bike get going. As you come to stop, shift to neutral and stop the engine. If you miss neutral, just stall it out with the rear brake. Hitting the kill switch while the motorcycle is still rolling in gear can have the effect of trying to toss you over the handlebars.)

To upshift without the clutch, you shift pretty much as you normally would. As you back off the throttle, upshift and roll the throttle back on. If done properly, you should not feel any fore or aft jerking sensation. In fact, all your shifts up and down, clutch or no clutch, should be smooth. It’s one of your best indications you’ve made a good shift.

Downshifts are a little trickier. As you start to decelerate, you need to blip the throttle gently to unload the force on the gearbox and get it to that coasting state. This is a good practice for downshifts whether you use the clutch or not as it also helps keep everything spinning in synch. Then, as you blip the throttle, push down on the lever and complete your downshift while closing the throttle again if slowing or opening it back up if accelerating. Again, you shouldn’t feel any fore and aft jerkiness.

What’s a throttle blip? A very gentle and quick opening of the throttle that raises the engine speed 1-2 thousand rpm. You don’t need to grab a handful of throttle to complete these maneuvers.

You should also hear a positive mechanical acknowledgement that the engagement dogs have fully seated. On sportbike this might be a gentle click or "snick" while a big cruiser with give off a fairly loud metallic sound usually described as a "clank." If you don’t get this, you may not have fully engaged the dogs. Here, it’s best to shift to another gear and back again to make sure everything is fully engaged before applying much throttle. Otherwise the transmission may start popping out of gear with greater and greater frequency until repairs need to be made.

So, get out there and experiment a little. Start off by using full clutch disengagement during shifts. When you’ve gotten to the point where you’re smooth and proficient, try using less clutch lever travel, upshifts first and then downshifts. Finally, if you want, you can try a few shifts without the clutch, again starting with upshifts and then trying downshifts. If you’re doing it right, the motorcycle should remain smooth, there should be no extra noise from the transmission or drivetrain, and the shift should be completed quickly. If you’re holding pressure on the shift lever while the engagement dogs grind into place, you’re not doing it right.

Now, some like full use of the clutch, some partial use as I’ve outlined, while others may not use the clutch at all for shifting. Lots of racers don’t use the clutch for upshifts and only use it lightly for downshifting. Then again, they are normally prepared to examine and rebuild their transmissions a lot more often than your average street rider. I’ve also outlined my personal preference of using partial clutch disengagement on most modern motorcycles. If it’s an old bike I’m riding, then I use full clutch travel and take my time with the shifts. Old Harleys, Triumphs, BSAs and BMWs are especially bad in this regard. You just can’t hurry the shifts.

I’m also going to dispel another common bit of moto folklore, namely the practice of preloading the shifter. Yes, this may hasten the shift process and may even seem to make the shifts more positive in their engagement, but think about what it’s doing to the transmission. You’re now applying pressure to the shift selector mechanism and one of the shift forks. The transmission doesn’t shift yet because it’s in an acceleration or deceleration state. In fact, if you backed off the throttle momentarily, the transmission would likely complete the gear change just like any other clutchless shift. A lot of old timers will tell you this is the way to go. The problem is most of them don’t know how the transmission operates. I also see a lot of them complaining about how their transmission jumps out of gear if they don’t preload between shifts. If you need to preload the shifter to get the transmission to successfully complete shifts, chances are good it’s already damaged and needs repairs. Don’t preload the shifter, OK?

Modern motorcycle transmissions are better now than they’ve ever been. Learn to shift smoothly at all times and then try using a little less clutch action. You just might like it. And don’t forget to be firm and deliberate with the shift lever and use all of its available travel. Like all that’s best in life, not too fast and not too slow, but just right!

 

nice read, i feel smarter now <!-- s --><img src="{SMILIES_PATH}/icon_biggrin.gif" alt="" title="Very Happy" /><!-- s -->

 

Same way i felt after readin that article for the first time. Give you a nice insight on hwo the gear box works.

 

really good article, shandu. i did not realise one could change gears without clutch - did you practice it on fzr?

 

Yes I did practice it on my fzr. I also got the clucthless shifting down.

And when you shift without the clutch i didn't feel any difference than when using the clutch it was smooth.

But i don't do it often.

But its possible. I did so can you. just practice

 

lol

First off 1st to 2nd, 2nd to 1st clunk is normal and is not bad in any way, the clutch is there for a reason ive blown a dirt bike box by doing clutchless changes but it comes down to want u want I gess. Sinoz with that noise it could be the clutch cradle rattling, clutch cover, clutch springs, bearings.

Thats my view

 

It could also be as simple as the clutch not fully engaging too. When travelling the clutch engages easier (engage=when clutch lever pulled in, disengage=lever released).

I used to have my clutch lever adjusted so it didn't fully engage until it almost hit the handlebar, but one day my fiance's dad adjusted it so it only took 2-3 cm pull to fully engage. It confused me when I first started riding it (I couldn't figure out why my bike wasn't pulling when I had the clutch lever about half-way). But since becoming comfortable the adjustment I've had far fewer (virtually no) bad shifts, and this includes false neutrals.

So the clunk could simple be forcing your gear box to change without clutch actually being fully engaged? Assuming you are doing clutch shifts of course... (there will always be a small clunk when the clutch fully disengages into first gear).

 

he

This is true also. I gess by what has been said in this forum there could be many things. Best thing to do is have a long hard look.