'17s.... no KLANK??

[Rockout Rocker Products]

It's been widely reported both by the MOCO and actual riders that the 17's no longer KLANK into 1st. Why? I've compared the parts diagrams from the 17 to the previous "Assist & Slip" clutch and although the part numbers are different they appear to be identical.

The KLANK is caused for the most part by the parasitic drag on the clutch plates, maybe a new friction material? Something in the trans keeping the shaft from freewheeling?

Maybe they're running Mobil 1 syn ATF in the new primaries?   

[rbabos]

It's been widely reported both by the MOCO and actual riders that the 17's no longer KLANK into 1st. Why? I've compared the parts diagrams from the 17 to the previous "Assist & Slip" clutch and although the part numbers are different they appear to be identical.

The KLANK is caused for the most part by the parasitic drag on the clutch plates, maybe a new friction material? Something in the trans keeping the shaft from freewheeling?

Maybe they're running Mobil 1 syn ATF in the new primaries?   

Can't see it. As you say, it's from breaking the plates free on a moving mass . Vrod has slip assist and it has a first gear clunk also. Just more low keyed, like a metric, likely due to less rotational mass involved.
Ron

[garyajaz]

the one I watched and heard leave several times did not clunk bad.
it was idling LOW.

clunk on my 03 dyna is also less now I have a mik 42 and 204 cams and idle lower than stock.

[masstch]

The new trans has a "scissor" gear on countershaft first that effectively eliminated the gear lash in first.


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[FSG]

   first gear countershaft is using a "scissor gear" to reduce neutral rattle

[Rockout Rocker Products]

I thought the noise was caused by the mainshaft freewheeling, & the dogs smashing into their pockets in the next gear? (Forgive the technical terms, it's how I roll)

Neutral rattle should have nothing to do with it?

[PoorUB]

The new trans has a "scissor" gear on countershaft first that effectively eliminated the gear lash in first.

The scissor gear has little to do with the "klank" but more to do with tranny rattle. My 2016 does not klank into gear either.

I thought the noise was caused by the mainshaft freewheeling, & the dogs smashing into their pockets in the next gear? (Forgive the technical terms, it's how I roll)

Neutral rattle should have nothing to do with it?


That is my understanding.

[hd06]

 The klunk never bother my.

[masstch]

Actually, and this is my pure speculation, I think the clank is a combination of two things: gear lash between 1st main and 1st countershaft & 2.) primary component "slap".

When idling in neutral, everything is spinning from the crank to the 1st CS gear *except* for the countershaft and shift ring. When you grab the clutch and disengage it, all the things are STILL spinning, because the oil in the cutch plates doesn't 'let go' just because it's disengaged.... until it's forced to let go. The  clutch/main shaft/1st gear being suddenly stopped from rotating by the shift dog engaging the first c-s gear causes the first gear lash to be taken up AND  (because this stops the mainshaft suddenly) clutch discs are forced to rip free from the oil drag holding them to the plates, this transmits a lot of shock to the rotating primary components. The primary chain jerks when you drop it into gear because of the clutch discs having to tear free of the oil. This causes the primary make some of the clank.  The M8 has all new primary plus the scissor gear.
(Run a really light primary lube and most of the clank goes away)

[Rockout Rocker Products]

I must be missing something.

Not sure how the new "scissor gear" helps quiet a gear slamming into another & going from 1100 RPM to zero in an instant.

You're right about the thinner oil, my choice being the Mobil 1 syn ATF.

On a side note..... anyone notice the new "sound dampener" on the inside of the primary cover? I can see how that might quiet some comp noise.

[dmrdn]

Rode 3 different models today. All 3 had the Klank/Klunk in all gears. When you get on it you feel it in the clutch lever

[masstch]

I must be missing something.

Not sure how the new "scissor gear" helps quiet a gear slamming into another & going from 1100 RPM to zero in an instant.

The answer in in the inertia; the 1st cshaft gear itself has little inertia. If it were spinning on the cshaft all alone (no mainshaft gear meshed with it) and you slide the dog into it, it would stop with hardly a *tic*.
However, the 1st mainshaft gear, the whole mainshaft, the clutch hub, clutch friction discs, the steel plates, the clutch basket, etc etc amount to a huge amount of inertia.... And ALL of that inertia, plus the shear force to slip the clutch from the oil, all of that is turning the 1st mainshaft violently toward the (now stopped) 1st cshaft gear.
Does that help?

Edited to remove an analogy that wasn't helpful.

[04 SE Deuce]

Delete, ya changed the example.

[Rockout Rocker Products]

I must be missing something.

Not sure how the new "scissor gear" helps quiet a gear slamming into another & going from 1100 RPM to zero in an instant.

The answer in in the inertia; the 1st cshaft gear itself has little inertia. If it were spinning on the cshaft all alone (no mainshaft gear meshed with it) and you slide the dog into it, it would stop with hardly a *tic*.
However, the 1st mainshaft gear, the whole mainshaft, the clutch hub, clutch friction discs, the steel plates, the clutch basket, etc etc amount to a huge amount of inertia.... And ALL of that inertia, plus the shear force to slip the clutch from the oil, all of that is turning the 1st mainshaft violently toward the (now stopped) 1st cshaft gear.
Does that help?

Edited to remove an analogy that wasn't helpful.

I understand completely about all that stuff spinning together, it's what I've been saying.

What I don't understand is how the scissor gear stops it from spinning together, then slamming to a complete halt.

[masstch]

The scissor is essentially a spring. It's softening the blow as the  lash is taken up.


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[Rockout Rocker Products]

The scissor is essentially a spring. It's softening the blow as the  lash is taken up.

I get your theory, but I'm not sure how much cushioning there could be. The scissor gear teeth are aligned with the teeth on the main gear when installed, not offset by some big amount. Rattle control I can see, not much else.

[PoorUB]

I understand completely about all that stuff spinning together, it's what I've been saying.

What I don't understand is how the scissor gear stops it from spinning together, then slamming to a complete halt.

Don't worry, I don't think you are the only one that does not understand how a scissor gear would stop the klunk, because it shouldn't.

[masstch]

Note that I didn't say it stopped the klunk.... But I think it's one component in a group of new design changes that should cumulatively help reduce noise. I don't know how successful they've been. I get the theory, but haven't ridden one, yet.


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[76shuvlinoff]

I got rid of a lot of the initial the first gear Klanks in my 2012 EG.
Pull the clutch in,
Start it (in the garage),
Hold the clutch in while walking it backwards about 30 feet until I have it pointed out the driveway.
Drop it into 1st, most of the time not even a click.

  Then in the next time or 3 it makes a big fat liar out of me.

[HV]

Those of us who have owned shovels get nostalgic when we hear a klunk going in to gear..

[PoorUB]

Note that I didn't say it stopped the klunk.... But I think it's one component in a group of new design changes that should cumulatively help reduce noise. I don't know how successful they've been. I get the theory, but haven't ridden one, yet.

But the thread is about the klunk, not reduced driveline noise, two different things.

[Herko]

Prefer the klunk going from neutral into first as well.
On my good ol' 2004 RK, the klunk gives me a definitive that it's in gear.
It's when it does not klunk, it's about 50/50 that it's fully in 1st gear.

[Templer]

Just yesterday Aug 27,2016 watched a customer buy a 2017 from the dealership. Bike sounded good BUT myself and several other all noted AT the same time that it still had the "clunk/klank" into  1st gear. Did note in my mind on how fast the rider pushed down on the shifter in relation to the amount of time from clutch pulled in FULLY to the actual shift. If I pull the clutch in (all the way to the perch stop) and hold it for a short time THEN push down on shifter, sometimes there is NO clunk at all. Do not know why but it clunked/klank like my 07 6 speed does sometime!!! I hear the DD7 does not have the klunk by design but have not heard one in use. Is it also noted or myself that it changes with temp of the motor/tranny cold ver hot? The 2017 was dead cold. I have heard new baggers that you wanted to look under the bike to make sure it didn't drop its inners on the ground!!!

[76shuvlinoff]

Those of us who have owned shovels get nostalgic when we hear a klunk going in to gear..

  got rid of that klunk too,installed a Rivera clutch and put that tranny on the shelf. It needs a LOT of love.

[rbabos]

The scissor is essentially a spring. It's softening the blow as the  lash is taken up.

I get your theory, but I'm not sure how much cushioning there could be. The scissor gear teeth are aligned with the teeth on the main gear when installed, not offset by some big amount. Rattle control I can see, not much else.

:up:That's all the damn thing will do, is take up gear lash. The clunk is from stopping the shaft abruptly with the dog with some residual drive component in play from the clutch plates stuck together which is the primary cause. Poor adjustment or thick fluids.  The sudden stop breaks the oil bond on the plates, then the steels and fiber plates float past each other. The clutch pack components have a fair amount of inertia so the lighter the oil used the quicker they can separate inducing less noise to that violent action of slipping into first. In fact if the plates can seperate during the time the clutch lever is pulled in, the trans will make no other noise then a click. Seen it many times with pulling the clutch in, reving the engine a few times to make the plates break the bond, then slip in into gear. Just a click sound.
Ron