On-off throttle knocking in gear

[Recont]

Hi,

After FZ6 been stood for 2 years got it prepared for MOT today and one of jobs was chain and sprocket replacement. All was done using torque values from manual and when I took bike for a quick ride around noticed knocking in gear when on-offing throttle, like there is a lot of backlash on front sprocket shaft. Video link below:

Any ideas what could it be?

 

[Gary in NJ]

How much slack is in the chain? It should be 50mm up and down.

Have you confirmed the alignment of the rear wheel?

 

[TownsendsFJR1300]

That chain is WAY TOO TIGHT, period, but that's not the issue.

What did you use to HOLD the FRONT sprocket while to loosen and tighten the nut?

It appears all that play is at the front sprocket....

After re-adjusting your chain (to 50mm's), put a light load on the bike, go slow (1st gear only) and see if there's any "skipping" in the drivetrain.

Also, for video, turn off the machine, put in first gear on the CC, (and again after, 2nd gear-to see if there's any change).
Please video the forward/backward play in the front sprocket. The rest of the bike isn't necessary..

I suspect something in the transmission is not good...

 

[Recont]

How much slack is in the chain? It should be 50mm up and down.

Have you confirmed the alignment of the rear wheel?

It is certainly less than that but if you look when I turn rear wheel in gear front sprocket has a lot of backlash.

 

[Recont]

That chain is WAY TOO TIGHT, period, but that's not the issue.

What did you use to HOLD the FRONT sprocket while to loosen and tighten the nut?

It appears all that play is at the front sprocket....

.

Used old, split chain for that. The nut came loose pretty easy. Had chain more slack at first but had same knock.

Googled the symptom and found several threads for other bikes and people were saying it is normal but in my case that is a bit too much.

 

[TownsendsFJR1300]

That isn't normal, no way...

Something to rule in or out the transmission:

- Pull the spark plugs
-Spin the wheel forward, in several gears and feel/listen for ANY skipping.


Is that play the same in different gears?

.

 

[Recont]

That isn't normal, no way...

Something to rule in or out the transmission:

- Pull the spark plugs
-Spin the wheel forward, in several gears and feel/listen for ANY skipping.


Is that play the same in different gears?

.

Same play in all 6 gears.

 

[Gary in NJ]

I watched that video too quickly and didn't notice the demonstration of the slipping before you started the engine.

Can you remove the front sprocket and take a photo of the shaft/spline to see if it is rounded or missing a tooth. Same for the sprocket.

Hopefully the sprocket is damaged...otherwise that case may need to be split.

 

[Recont]

Not looked at front sprocket as per advice above yet but found 2 videos on YT for sprocket replacement and in both there seem to be backlash in gear on front sprocket.

Here is one of them @ around 7:20

 

[Gary in NJ]

The noise you are hearing (and probably feeling) should completely disappear under load. If you are hearing/feeling that while riding, then something isn’t right.

 

[Motogiro]

Are you sure the rubber rear sprocket to rear wheel dampers are in place?

 

[TownsendsFJR1300]

Here's my '07, 33,000 miles:

https://flic.kr/p/2oLbarK