Clunking Trans

[spalkin]

This guy's got eight thousand seven hundred posts! He never, EVER has anything to contribute. All his posts are around twenty rediculous words or less. When you see Barney, skip to the next post! This is the type of person who watches Dukes of Hazzard and has to have it explained for him. Watch his next post. He'll keep digging himself in. LOL

 

[RadioHowie]

This guy's got eight thousand seven hundred posts! He never, EVER has anything to contribute. All his posts are around twenty rediculous words or less. When you see Barney, skip to the next post! This is the type of person who watches Dukes of Hazzard and has to have it explained for him. Watch his next post. He'll keep digging himself in. LOL

And YOUR 9,112 posts? Oh, wait...that's your MEMBER number! Sorry for the mistake.

Tell you what, if YOU don't want to read the 'nut's posts, click his Profile, select Options, then Ignore User, but don't presume upon yourself that many of us don't enjoy and appreciate his contributions to the FJR community.

You just marked yourself as a jackass to suggest to the other 9100+ forum members to skip anyone's posts based on your opinion. What an ego you must have to think you could speak for everyone on the forum.

You certainly have proven the old saying about opinions and assholes.

Oh, the word is rIdiculous. But I see you did spell Hazzard correctly. Hmmmmmm.

 

[Kevin Daly]

At the risk of rekindling what appears to be a very interesting combo technical thread and bitch slap I have some questions caus'n i a bit confused.

Huck, your talking about the clunking that occurs whe you shift... on a shafty? dont they clunk and isnt the reason (that you described) always been the case. EVERY shaft drive bike I have owned has done this. There is always play in the driveline that traces back as you describe, at least as far as i know. But interesting.

I saw a couple comments about oils in the thread (which incidently I am adding to only now that I have read it). I am pretty confident that different oils will not make this go away as suggested but different viscosities do make it sound different (wow). I personally like the deeper thunk that comes from heaver weight oils!

As for the shifting technique, maybe i missed something here but if you dont preload the shifter how do you, can you, upshift effectively. I mean how do you shift in a timely manner. Clutchless upshifting, for example, leaves your powertrain disengaged for a fraction of the time a clutched shift will and is as silk smooth if done proper-like. Maybe i missed something??

Finally, dont nobody be dissin da Nut, or we'll be see'n you come Friday

-k

 

[Huck Fonda]

At the risk of rekindling what appears to be a very interesting combo technical thread and bitch slap I have some questions caus'n i a bit confused.Huck, your talking about the clunking that occurs whe you shift... on a shafty? dont they clunk and isnt the reason (that you described) always been the case. EVERY shaft drive bike I have owned has done this. There is always play in the driveline that traces back as you describe, at least as far as i know. But interesting.

I saw a couple comments about oils in the thread (which incidently I am adding to only now that I have read it). I am pretty confident that different oils will not make this go away as suggested but different viscosities do make it sound different (wow). I personally like the deeper thunk that comes from heaver weight oils!

As for the shifting technique, maybe i missed something here but if you dont preload the shifter how do you, can you, upshift effectively. I mean how do you shift in a timely manner. Clutchless upshifting, for example, leaves your powertrain disengaged for a fraction of the time a clutched shift will and is as silk smooth if done proper-like. Maybe i missed something??

Finally, dont nobody be dissin da Nut, or we'll be see'n you come Friday

-k

Yes, there has always been drive line lash, and always will be. What interests me about this model is that it's so much more pronounced. Why is it that other similarly constructed bikes don't clunk as much?

The net result is that the two transmission shafts aren't staying "connected". One shaft is turning at a different rate than the other, causing that gap in the engagement dogs to open up, then re-close suddenly when power is applied.

We can look at it step by step from the crank. Crankshaft is turning, that means that the primary gear on the clutch basket is turning, right? Well even with the clutch disengaged, there's usually at least a little drag between the plates, which means the main shaft is turning, or a least has a rotational aspect to it. You'd think that would be enough to keep the clearance closed, so why doesn't it?

Is it possible that the clutch disengages enough that there is no drag to the metal plates that engage the hub? I kind of doubt it. It may be that the main shaft bearings have enough friction to keep it from turning, but jebus, I hope that's not it. Think of all the power that would be gobbling up.

Maybe the drag is on the rear wheel end of things? Thoe parts all seem to move pretty freely on the center stand, but I haven't taken the time to think too much about the dynamics.

It could be that there is play created by the clutch drag, I don't know. I have a slow day at the office tomrrow, maybe I'll spend some time on this.

Oh, and thanks for bringing this back to reality. I still think it's a valid topic.

 

[twowheelnut]

And YOUR 9,112 posts? Oh, wait...that's your MEMBER number! Sorry for the mistake.
Tell you what, if YOU don't want to read the 'nut's posts, click his Profile, select Options, then Ignore User, but don't presume upon yourself that many of us don't enjoy and appreciate his contributions to the FJR community.

You just marked yourself as a jackass to suggest to the other 9100+ forum members to skip anyone's posts based on your opinion. What an ego you must have to think you could speak for everyone on the forum.

You certainly have proven the old saying about opinions and assholes.

Oh, the word is rIdiculous. But I see you did spell Hazzard correctly. Hmmmmmm.

Thanks for the back up, Howie, but sometimes, I forget to call for the septic tank to be emptied only to find rotting shit roiling out of the ground. Funny thing is, eventually the septic guy shows up and sucks away all of the bromidic, spent douche bags.

Sorry -again- for the derail, Huck. Carry on.

 

[Kevin Daly]

being a neuroscientist and not a mechanic, i would say all this you say sounds like the kind of stuff I have heard before but in the end its is really about how much rotational play your rear tire has and how much inertia/torque you engine has.

If you put the bike on the center stand and while off and in gear and rotate the wheel it is going to role back and forth. To me this and the resisitance of the engine defines the lash. Lash is bad and all bike makers want it to go away but for years it has been there (supposedly the C14 is not as bad??) and though I have not measured any of my shaftys in any other way than eyeball-o-metrically, they all have had about 2 inches of play on the center of the tread, give or take depending on wheel and tire size and the various internal mumbo jumbo. this is my experience based on having shaft drives back to 1984. Now maybe it seems like the lash is worse on the FJR becuase of it ST nature. That is, you have a giant muscle pulling on a relatively small body and when the play is taken up by the small body the muscle does not give (inertia) and when the muscle pulls the play is snapped away jerking the small body (torque). Like having my 6 lb pomeranian on the other end of a leash; only youre the pomeranian and the FJR is my arm; you can pull and I probably wont notice but dont piss me off or i'll break you neck.

I think also that particularly when accelerating this isnt even noticable if you practice clutchless shifting (of course I know shit about AE). And this gets back to my previous post. When proficient, shifting even while accelerting out of corners (as I know many others can) should be seamless. Now the lash is really only noticable in the transition between decelerating (and throttle closed) and accelerating. To this I would say again that technique will solve much of the lash problem. By cracking the throttle with a gentle trail brake you can maintain some tension on the drive train without disrupting the suspension; this i do if i feel my traction is/will be close to the limit like in a downhill corner. Set this up after my main braking before/as leaning into a corner, accelerate out and relieve the rear brake.

I am sure there are many that would say this is over thinking cornering, and i do admit that i am a bit detail oriented about cornering.

I cant say much about in town because I'd rather not ride if I have to be in town.

 

[spalkin]

"Okay, everybody, I'm a jackass. Let's all agree on that." -- RadioHowie 03/27/2007

OK, I'm in good company.

I just thought that someone with a member number of 10 could add more to help solve the problem.

Nobody's going onto any "ignore" list.

I didn't mean to offend Barney, I have to get used to him.

And, I was talking to Huck, not the whole forum.

The forum's good and I'm glad to be here.

 

[Kevin Daly]

"Okay, everybody, I'm a jackass. Let's all agree on that." -- RadioHowie 03/27/2007And, I was talking to Huck, not the whole forum.

next time your going to talk behind someones back try using the PM option that way you wont be talking behind someones back in fron of 'em :blum: :bb:

 

[Huck Fonda]

Skipping over the personal stuff, I'd like to continue the technical discussions (see forum title).

KD, you're right all the way. On shafties and the torque / resistance / muscle / pull thing, BUT, there still has to be a quantifiable differentiator between our bikes and the rest, and I think I found it. It came to me in the shower this morning.

(Easy now ladies... )

That pesky middle drive shaft has been bugging me. Its purpose is to dampen all of that tugging and jerking that the pommeranian is doing. Think about putting a spring in the middle of your leash. I contend that there are two possible aspects of the middle drive shaft that could be at the core of this:

1) The ramp configuration of the cam - If it's too steep, or not long enough, it will take higher loads for it to be effective. A light application of throttle will treat it like a solid leash, to keep that analogy going.

2) The tension of the spring - Again, if it's too tight, it will handle larger loads, but the little ones don't affect it at all.

The bike makes a fair amount of power and weighs a ton, so that damper system was probably designed for worst case scenarios of massive abrupt changes in throttle and vehicle inertia. Put a pit bull on the end of that spring loaded leash, and you might choke it some, but you won't break it's neck.

I'm half tempted to take the dang spring right off and see what happens. I need to look and see if the middle driven gear is secured axialy to the shaft first. If there's any change to the dynamics of the bike as I ride it (I'm sure there will be), I'd next consider cutting that spring down to see if I can't get it to perform a little better under lighter loads.

Just to clarify, the kind of clunk I'm referring to is associated with a low speed on/off throttle application. Not the one that comes with gear changes.

Stay tuned...

 

[Kevin Daly]

Well,

if you right then removing that spring should result in a rougher transition and if your really right replacing it with softer spring should soften the interaction between engine and tread. I think you should also be considering whether the EFI as designed provides to abrupt a transition between idle and just cracked. The throttle on the FJR seems a lot like my wifes Honda Civic. The car has basically two states: gas off and gas on. this will only compound the problem IMO

 

[Huck Fonda]

Well,if you right then removing that spring should result in a rougher transition and if your really right replacing it with softer spring should soften the interaction between engine and tread. I think you should also be considering whether the EFI as designed provides to abrupt a transition between idle and just cracked. The throttle on the FJR seems a lot like my wifes Honda Civic. The car has basically two states: gas off and gas on. this will only compound the problem IMO

I concur. If these things were carbureted, we wouldn't be having this conversation at all.

 

[Constant Mesh]

On the '08 that damper spring is being strengthened on the middle drive cam assembly. They are also adding an engagement dog (going from 2 to 3 dogs) on the 3rd and 4th pinion gears. All the other gears had 3 dogs and 6 engagement sockets. This should improve the 3rd to 4th shift quality.

From the Yamaha Canada site:

"Middle gear damper spring load is increased for improved feeling at clutch engagement and better shifting feeling overall."

"Revised 3rd and 4th pinion gears feature an additional engagement dog for improved shifting feeling."

I don't think the back-and-forth slack due to the size of the engagement dog sockets is all that big an issue. This transmission is no different than others in this regard.

The vast majority of transmission clunk is due to differing shaft/gear speeds when a shift is executed. If the two gears are turning at about the same speed when the dogs mesh with the adjoining gear's engagement sockets very little noise will be heard.

But if the two gears have substantially different speeds then the dogs will clang hard into the engagement sockets as the two gear speeds become one.

The AE has no control over engine speed. So it's no better than a manual shifter at getting smooth, quiet shifts. Its only advantage is its speed in executing a shift. Once a shift is called for the AE shifting servo may likely move the shift drum, etc. much more rapidly and crisply than someone's foot/toe. And the less transition time there is between the release of the dogs from one gear and the engagement of the dogs in the next gear minimizes how the clutch drag affects the shift.

One can get very quiet shifts from the FJR if you match the engine speed with the gear being selected. But, of course, it's almost impossible to make a quiet neutral-to-1st shift when you're sitting motionless unless the engine's off.

For that reason I always shift to 1st gear before I start the engine. I don't like to hear that 1st gear clang. I break the clutch plates loose as I roll the bike from the garage to the driveway. This seems to reduce the load on the starter when I start the engine in 1st gear.

 

[Huck Fonda]

Again, and maybe I wasn't 100% clear, the gear change clunk isn't the one that annoys me. Its the low speed throttle transition clunk. I'm approaching a red light, down shifting, light turns green, and I roll on the throttle to a very loud clunk. Sometimes a series of them if I'm a gear too high.

The added spring tension should help dampen out the "shudder" some as will the change to the oiling of the clutch basket. I fear, though, that this won't address, and may even exacerbate the on/off clunk. That's the big dog situation again. When the inertia of the bike is vastly different than the engine speed.

I'd like to be able to try different ramp shapes. Maybe a "C" shape instead of a "U". More opportunity to allow low inertial difference damping, but still enough to dampen the larger differences. Since that's a lot of work and beyond my skills, I'll play with spring tension some.

The increase in number of dogs is simply intended to give any given gear set more opportunity to engage. So as you say, Mesh, it should help the transition feel smoother.

I used to try for those "perfect" shifts on bikes with a manual clutch, I think it's even harder on the AE because you're playing against the genie in the box.

 

[S76]

Huck,

Thanks for the discussion. I enjoy the "theory" talk and find I always learn something from these discusions. I had planned on going down that same road this winter for the same reasons. You gave me a head start.

However, I do not enjoy the negative input from those that have nothing constuctive to add, but then again I don't like all the food in the store either, so I just bypass the rotten fruit.

 

[Ignacio]

And, I was talking to Huck, not the whole forum.

Pstt! Just for future reference....that's what Personal Messages are for. They're a great way talk about people behind their backs.

When you post in the forum...it's like everybody can see what you post....it's crazy! :blink:

I didn't mean to offend Barney, I have to get used to him......The forum's good and I'm glad to be here.

Good deal. Now we can get back to Huck's clunking discussion...

 

[Constant Mesh]

One thing you could do on the AE is call for an upshift just before you roll on the throttle. Depending on how quickly the shift is executed this might force the computer to slip the clutch a lot which would tend to absorb the slack in the system.

Any driveline slack resulting from the small back-and-forth motion of the dogs in the engagement sockets would tend to be reduced by the reduction affect of the secondary gearing. The farther the slack producing component is from the rear wheel the less effect it will have on driveline looseness -- one degree of component rotational slack produces a larger effect as it's introduced into the system closer and closer to the rear wheel.

Ranking of Effect (nearness to rear wheel)

-- Rubber? Drive Hub Dampers in rear wheel (dampeners?)

-- Splined Interface between rear wheel and drive

-- Spiral Bevel Gear Interface in drive

-- Driveshaft Interface with drive

-- Driveshaft U-Joint

-- U-Joint Splined interfaces

-- Spiral Bevel Gear Interface in middle drive

-- Spring Damper in middle drive (dampener?)

-- Spur Gear Interface between transmission output shaft and middle drive

-- Spur Gears/Shaft Splines, etc. in transmission, etc.

-- Engagement Dogs in transmission

-- Clutch Housing shock absorbing springs

-- Etc.

 

[Kevin Daly]

I'm approaching a red light, down shifting, light turns green, and I roll on the throttle to a very loud clunk. Sometimes a series of them if I'm a gear too high.

Ok mine doesnt do that (not an AE though). I feel the lash but I dont hear a "very loud clunk"

Does anyone else other than HF?

 

[Huck Fonda]

Thanks S76. As others will, I found out that empty inflamatory rhetoric doesn't get you too far here. Water off a duck's back. I'm trying to keep focused on the core issues until I get a chance to meet some of these guys. Then we'll all know that any $hit slinging is just in jest for sure.

Mesh, I completely see what you're saying. What I was / am looking for in this is a vaiable in the power flow. The connection points you mention are all valid locations for some minor tolerance, and the stack up is cumulative for sure.

When I took the side cover off and was able to observe the right end of the middle driveshaft, It allowed me to conclude that from there back to the rear wheel there wasn't anything that was excessive (by feel and by gut) in terms of play. Also, there was little that could be adjusted to any significant degree.

Forward of the middle drive shaft is similar. I can't eliminate any of the part to part clearances from the middle driven gear forward. That leaves the spring and ramp as possible items that could be manipulated to help reduce the hammering I get once in a while.

As the ramp's profile would require removal of the middle drive shaft, I'm going to rule that out. I can't have my bike out of service that long. The spring might help. If it's softer, the input side of the cam will be allowed to "climb" the output side a little earlier, and so may be more effective in dampening the difference between the two relative speeds. Down side is that if the softer spring is more responsive, what will it do under the high torque loads that it was originally designed for? It's highly likely that the spring rate and the ramp shape were conceived together, so upsetting the balance will yield some (to me) unpredictable result.

As far as "snicking" up another gear, if I'm already a gear high, the AE won't let you grab another, but your idea is sound. If left in a higher gear, the clutch friction zone (between initial engagement and full engagement) is much longer. So it will be an easier take-off, but then the forces have already taken up the slack, and the initial battle has already been won.

Low RPM, off throttle, higher gear than appropriate (will try lower on the way home tonight), puts a kind of "negative" force on the driveline, or just plain old decel force if you will. Now open the throttle, and the force tries to go positive (accel), but it doesn't, or cant, and gets rebounded back the other way. The dog leash with no spring. Dog takes off, takes up slack in leash, snaps back, runs off again until it can pull evenly. Another way to think of it is like towing just about anything. You always take up the slack first to avoid this phenominon, whish breaks tow straps, cables, chains, whatever.

Now bear in mind, I'm making most of this up as I go, based on my analytical arse. It's all theory until a change is made somewhere (back to available options), and the result documented.

Sorry for so many words everyone. I'm a little slow at work, and so have too much time to ramble on in this stream-of-consiousness way. I'll try to be more brief as possible.

 

[ELP_JC]

There're a lot more components on a shaft drive than chain, so extra driveline lash is a fact of life. If somebody doesn't think you have some, just close and open the throttle abruptly and you'll feel/hear it (and this applies to the chain bikes as well, but to a lesser degree). I personally don't care if it's 1-1/2 or 2 inches; it'll be there, and the only solution is THROTTLE CONTROL. I honestly don't feel the FJR has any more slack than my most recent shafties (BMW K1200RS, GL1800, and Valkyrie). But yes, the BMW and FJR require a more precise approach due to their finicky injection. After riding the BMW for over 5 years, it's second nature to me now, and I don't have any PC, G2, etc.

And I fully understand how some of us are obsessed about different things, so I'm not dissuading you to stop looking for a fix at all. My point is that a bit of 'wrist conditioning' can circumvent the problem, that's all. Good luck.

JC

 

[Huck Fonda]

There're a lot more components on a shaft drive than chain, so extra driveline lash is a fact of life. If somebody doesn't think you have some, just close and open the throttle abruptly and you'll feel/hear it (and this applies to the chain bikes as well, but to a lesser degree). I personally don't care if it's 1-1/2 or 2 inches; it'll be there, and the only solution is THROTTLE CONTROL. I honestly don't feel the FJR has any more slack than my most recent shafties (BMW K1200RS, GL1800, and Valkyrie). But yes, the BMW and FJR require a more precise approach due to their finicky injection. After riding the BMW for over 5 years, it's second nature to me now, and I don't have any PC, G2, etc.And I fully understand how some of us are obsessed about different things, so I'm not dissuading you to stop looking for a fix at all. My point is that a bit of 'wrist conditioning' can circumvent the problem, that's all. Good luck.

JC

I guess I agree with this to some extent. Afterall, I've got 19k on it now with no more than some thought into a resolution. And on the way home tonight, I couldn't easily reproduce it without riding like a total nit.

The fact of it still keeps me thinking about what it would take to resolve it at the design level. It's more of a conversation topic now than anything else.