Sudden throttle disengage

[Gary in NJ]

Is it this?

https://www.amazon.com/Soupys-FZ6-L...pID=41gGOf5OyaL&preST=_SX300_QL70_&dpSrc=srch

It's called a "lowering link", but it's not. It simply shortens the shock by relocating the eyelet.

So how much of your fork is showing above the triple clamp?

(still SMH that suspension changes were made without checking sag)

 

[BitesWhenBitten]

I'm not sure what a lowering kit on a the FZ6 would consist of. The FZ6 uses a linkless shock, so there aren't any traditional lowering links (nor should they be used because they change the ratio). Perhaps a shorter spring was installed. Then that begs the question - "what rate"?

Raising the forks in the triple clamps effectively decrease rake and trail. Rake is the effective steering head angle. On the FZ6 fork angle and steering head angle are one in the same. 25 degrees is already on the "sporty" side of things. As a point of reference, Standard bikes are typically in the range of 25 to 28 degrees, Cruisers are in the range of 30 to 35 degrees, and race bikes are 24-25 degrees. So you can see you really don't want your steering much faster then what Yamaha has already provided. Trail describes the stability of the steering as it relates to the rake. In the range of 100mm (4 inches) is fairly common for a standard and even sport bikes. The FZ6 is 98mm (3.78 inches) so it's once again on the sporty side of things.

By raising the forks you may have decreased rake (faster steering) and trail (less natural stability). I say "may have" because I don't know what was done to the shock, nor do I (or you) know the sag settings. I guess the point of the post is this; don't change things until you understand the effect of the change. If you don't NEED the suspension lowered (i.e. you can't properly touch the ground) - then don't do it. If you need the suspension lowered, and now you have an unstable steering geometry, than you need to address that through other means, such as a steering damper.

I would never ride a bike that makes me uncomfortable. Unpredictable handling is #1 on that list.

I trusted the mechanics working on the bike to make that call when I asked if lowering was possible.
My understanding is they did a search on Amazon for a lowering kit by the make/model /year and found a match.
At the time I had to have it to ride the bike well. Since then I've learned other techniques to hold my balance without needing full contact.
Obviously if I or they (which they should have) understood the possible consequences of lowering the bike, I never would have done it.

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[BitesWhenBitten]

Is it this?

https://www.amazon.com/Soupys-FZ6-L...pID=41gGOf5OyaL&preST=_SX300_QL70_&dpSrc=srch

It's called a "lowering link", but it's not. It simply shortens the shock by relocating the eyelet.

So how much of your fork is showing above the triple clamp?

(still SMH that suspension changes were made without checking sag)

I'm assuming that's the piece

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[BitesWhenBitten]

Is it this?

https://www.amazon.com/Soupys-FZ6-L...pID=41gGOf5OyaL&preST=_SX300_QL70_&dpSrc=srch

It's called a "lowering link", but it's not. It simply shortens the shock by relocating the eyelet.

So how much of your fork is showing above the triple clamp?

(still SMH that suspension changes were made without checking sag)

I can measure the distance above when I get home.

Describe the triple clamp so I know I am measuring the right length.

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[BitesWhenBitten]

General update:
SD card has been recovered from the side of the rode at the wreck spot.
If video is viable I will let you know definite answers to some of the questions I've gotten.
Also, he noticed an inch sag in the road where I went down, you can't see the sag when riding over it, you simply have to pull over and inspect it.

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[Gary in NJ]

I can measure the distance above when I get home.

Describe the triple clamp so I know I am measuring the right length.

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The triple clamp connects the fork tubes to the bike. There are two of them, a lower and an upper. If you are looking at the bike from a riding position, the upper triple clamp is the piece of aluminum that the handle bars attach as well as the fork tubes. There is also a large nut in the center. So when you look at the fork tubes, are they protruding above the t-clamp? How high are they protruding?

 

[TownsendsFJR1300]

Describe the triple clamp so I know I am measuring the right length.

Top of the fork tube is connected to the top triple clamp
(Shown is the stock setting):

 

[BitesWhenBitten]

Top of the fork tube is connected to the top triple clamp
(Shown is the stock setting):

Gotcha, these are mine

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[BitesWhenBitten]

Top of the fork tube is connected to the top triple clamp
(Shown is the stock setting):

I'd estimate it's a little over an inch

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[BitesWhenBitten]

Look just under the left side of the fuel tank. You'll see a "disc" with TWO cables attached to it. One on top, one on the bottom.

One is the PULL (acceleration) cable, the other is a safety RETURN cable.

That disc, when turned (with the cables) opens and closes the throttle (and engine RPMs). If it doesn't move with the throttle movement, you have a broke cable (not likely)..

And your correct about the engine stopping when tipped over. There's a "Tip Over Switch" under the RS pod that kills the engine when you tip / fall over.
Nothing to re-set, just lift the bike up. If your curious, remove the RS pod, there will be a black rectangular unit that has "UP" printed on it...

Throttle bodies move well

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[TownsendsFJR1300]

That's a bunch of drop.....

It's VERY possible between the "drop" and sag(in the forks), you very well may have bottomed out the forks with the lower triple. You may see a NEW dimple/crack in the top of the fender..

Good to hear the throttle cables are ok.

Between the potential kill switch failing(at least loss of power), the lowering (tendency to de-cel wobble) and the dip in the road, I think you experienced the "perfect storm".


BTW, the fork sag with the stock fork is considerable (at least 1.5"). I'd suspect simply putting the forks back to stock height would be a big help, especially for your higher speed cruising.

The air Schrader valve in my fork caps are pressurized to about 16 PSI (each leg). That alone picked up the nose and got rid of all the "mush" in the forks (and is adjustable)...

 

[BitesWhenBitten]

That's a bunch of drop.....

It's VERY possible between the "drop" and sag(in the forks), you very well may have bottomed out the forks with the lower triple. You may see a NEW dimple/crack in the top of the fender..

Good to hear the throttle cables are ok.

Between the potential kill switch failing(at least loss of power), the lowering (tendency to de-cel wobble) and the dip in the road, I think you experienced the "perfect storm".


BTW, the fork sag with the stock fork is considerable (at least 1.5"). I'd suspect simply putting the forks back to stock height would be a big help, especially for your higher speed cruising.

The air Schrader valve in my fork caps are pressurized to about 16 PSI (each leg). That alone picked up the nose and got rid of all the "mush" in the forks (and is adjustable)...

Yeah, I'm going to take it to a shop when it's rideable to have them undo the lowering and look at the forks in general.

I'm looking at the kill switch right now, very little corrosion but still going to brush it.

And unless I find this ball bearing in a minute, I'll have to buy another.

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[BitesWhenBitten]

Update:
I have the final cut of the wreckage footage. Or at least as much as the software could recover, I had to use some black magic with several different programs/operations to get it.
I figured I would post it here so you guys can tell me what you think.
The very last frame before the loop you can see the bar start a violent right.
I wish there were more, and that the audio at the end were clear, but some key items can be taken from this.

Rotated Version: https://youtu.be/_r491XOPfJA

Raw Version: https://youtu.be/7z5meGiYKXM


Thank you guys for all the advice!

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[darius]

I watched the video. Never had this issue on my FZ6, but my first bike mysteriously cut out on the highway in the same way and would not restart until it later wanted to. Turned out the bike had gremlins that the original owner and bike shop were never able to resolve despite replacing the fuel pump.

On a ride with a friend w/ a Ducati, his cut out similarly soon after refueling. Opening the fuel cap allowed the bike to restart so at least it seemed to be vapor lock in that case (fuel starvation caused by inadequate fuel tank venting.)

I hope you figure out the gremlin with the top mechanics on here. G/L.

 

[BitesWhenBitten]

Update:
I have the final cut of the wreckage footage. Or at least as much as the software could recover, I had to use some black magic with several different programs/operations to get it.
I figured I would post it here so you guys can tell me what you think.
The very last frame before the loop you can see the bar start a violent right.
I wish there were more, and that the audio at the end were clear, but some key items can be taken from this.

Rotated Version: https://youtu.be/_r491XOPfJA

Raw Version: https://youtu.be/7z5meGiYKXM


Thank you guys for all the advice!

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Just to be 100% clear, the camera footage was too corrupted to recover at the point of the actual wreck. This just gives some context

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[BitesWhenBitten]

I watched the video. Never had this issue on my FZ6, but my first bike mysteriously cut out on the highway in the same way and would not restart until it later wanted to. Turned out the bike had gremlins that the original owner and bike shop were never able to resolve despite replacing the fuel pump.

On a ride with a friend w/ a Ducati, his cut out similarly soon after refueling. Opening the fuel cap allowed the bike to restart so at least it seemed to be vapor lock in that case (fuel starvation caused by inadequate fuel tank venting.)

I hope you figure out the gremlin with the top mechanics on here. G/L.

Thank you.
I figure returning the forks to their default height will resolve 99% of the issue, as I would never have laid it down if it hadn't wobbled. And then if there's some other issue with the kill switch or control unit, those can be covered if they reoccur WITHOUT replacing parts every time.

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[zixaq]

Thank you.
I figure returning the forks to their default height will resolve 99% of the issue, as I would never have laid it down if it hadn't wobbled. And then if there's some other issue with the kill switch or control unit, those can be covered if they reoccur WITHOUT replacing parts every time.

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Returning forks to stock height might cause different geometry problems if you don't unlower the rear at the same time.

It looks like there might have been a mild edge trap at the shoulder transition that could have started a wobble. Hard to tell from the video.

 

[TownsendsFJR1300]

About the only thing I could tell from the video is you never lost electric to the dash.

Should the Kill Switch be the issue, I'd think, in that video, the tach just shows the engine slowing down (still turning obviously but unknown if it's developing power).

Your front brake lever, it looks like it's al the way in???

While on that subject, have you ever lifted the ft tire (on the center stand) with a scissor jack under the header and checked to make sure your front calipers are NOT binding / dragging excessively? It's NOT unusual for the seals to harden up and cause the wheel to drag (sometimes a lot), mostly on the S2 bikes

 

[BitesWhenBitten]

About the only thing I could tell from the video is you never lost electric to the dash.

Should the Kill Switch be the issue, I'd think, in that video, the tach just shows the engine slowing down (still turning obviously but unknown if it's developing power).

Your front brake lever, it looks like it's al the way in???

While on that subject, have you ever lifted the ft tire (on the center stand) with a scissor jack under the header and checked to make sure your front calipers are NOT binding / dragging excessively? It's NOT unusual for the seals to harden up and cause the wheel to drag (sometimes a lot), mostly on the S2 bikes

I put shorty levers on so you can't see them well with my gloves in the way, I never pulled the brake.

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[BitesWhenBitten]

About the only thing I could tell from the video is you never lost electric to the dash.

Should the Kill Switch be the issue, I'd think, in that video, the tach just shows the engine slowing down (still turning obviously but unknown if it's developing power).

Your front brake lever, it looks like it's al the way in???

While on that subject, have you ever lifted the ft tire (on the center stand) with a scissor jack under the header and checked to make sure your front calipers are NOT binding / dragging excessively? It's NOT unusual for the seals to harden up and cause the wheel to drag (sometimes a lot), mostly on the S2 bikes

It was never an issue before, so I haven't checked.
I've only had the bike since January and before that it was sitting in a barn. Supposedly the guys who sold it to me checked everything.
But I'll add that to my list of things to have a shop look at.

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