FZ6 N transmission "slack"?

[raduph]

Hey guys, long time no see.

I'm still aboard the fz6 train, hoping to move up to an FZ1 this season, but that's another story.

For a while now I've been having some issues with my transmission, the issue was described very well on an aprilia forum, I'll quote the guy as it's the same issue I'm having:

"Hi Guys,


I have a 2003 model with 6500 miles on the clock.

Is any of you getting driveline slack on your capo? I.e. a 'delay' between accelerating and the rear wheel responding. And an obvious clunk once the chain begins to pull on the rear wheel.

I know that certain amount of slack on the gearbox and the output shaft are needed to make shifting easier, as these gearboxes don't have synchros, and I also know that certain bikes are worse than others (Yamaha FZ6!!), so I wanted to run this past you guys before I really start worrying.

It manifests itself at all times, but gets worse in higher gears and lower revs. So if I'm in 4th at 3k, throttle off and then throttle-on again I get a positive delay and a clunk before I get drive on the wheel.

It also happens when changing gear because I have to throttle-off and on. In between I get the clunk.

I just want to make sure that there's no known issues with output shafts or the like because I'm still within the 30 day warranty offered by the dealer I bought the bike from. So if there's something wrong I'll get them to fix it.


Cheers Guys!


Mich"

In the discussion they mentioned bad "cush rubbers" and worn out splines on the drive shaft.
I also think I remember having a striped nut holding on the drive pinion from when I changed the chain kit.

It's really getting on my nerves, any ideas?

Cheers.

Edit: The bike has 59.000 km on it atm, I've only done like 10.000 kms on it in 3 years and no abuse, I never redline and no wheelies whatsoever, and I mean never.
Serviced each season even if not doing 5000km, fresh filters, oil... the works.

 

[TownsendsFJR1300]

First off, driveshafts and chain drives are two completly different animals..


"I also think I remember having a striped nut holding on the drive pinion from when I changed the chain kit."

** Is your main sprocket nut /shaft damaged? is the sprocket tight? The sprocket is designed to be tight on the output shaft. If its not and flopping about, you have your answer...

Check/repair that possible issue before proceeding further.


____________________________________________________________________________________________________
Basic's first,

(1) Clean /lube and adjust your chain.

(2) Pull the sprocket cover and see if your ft sprocket nut is there and is
torqued down fully.

(3) There are rubber cushions in the FZ drive hub (easy enough to check)
but rarely (if ever fail). If left out accidentally, oh yea, they'll be
issues clunking/excess driveline slop.

(4) What shape is the drive chain in? I know its low mileage but if NOT
maintained you can have excess slop in it.


There shouldn't be ANY CLUNKING once your IN GEAR..

Slop in the drive line, IME, is minimal (if any, at least on my FZ-19,000 miles) and nothing like what you posted on the Aprilla forum(again, two completly different systems).

 

[raduph]

Evening,

Thanks for the quick reply.
I've already cleaned the chain with diesel and the slack is within parameters.
It can't hurt to check it, I'll measure the slack again, but I distinctly remember doing this when the problem first appeared and the issue remained even after correcting the slack.
This issue has been present since last season, I just haven't taken any steps to correct it until now.

It's already dark outside and I won't be able to see anything, so I'll hold off until tomorrow when I get back from work.

I really hope we're right and it's just a loose sprocket nut and/or incorrect chain slack, that output shaft seems a pain to replace.

Have a good weekend, whats left of it, anyway.
Cheers

 

[FinalImpact]

This may be a matter of interpretation as some (me) saw two different points of view. The mechanical aspect has been covered above.

"It manifests itself at all times, but gets worse in higher gears and lower revs. So if I'm in 4th at 3k, throttle off and then throttle-on again I get a positive delay and a clunk before I get drive on the wheel."

As best I can tell from that, what you refer to is Throttle Chop or the power application from OFF to ON is not smooth. So as you roll along in those higher gears and close the throttle, the bikes Fuel Injection system is literally starving the engine of much needed fuel to increase its Fuel Economy and reduce its Emissions. This Throttle Chop, lag, delay, snatch, bubble, - whatever you want to call it is inherent in the bikes Fuel Map. Its part of Modern Day Fuel Injection and trait that old carburetors did not suffer from.

It can be fixed or corrected but it takes time and money to change the fuel map.

Just so we are on the same page - follow this link and see if it sounds like the same issue: --> Link Fixing Throttle Chop, snatch, rewet, response time. Cheap!
The other option is to ride differently. i.e. select a lower gear and let the engine REV. Or, add a fuel controller to ADD FUEL to the 2 - 7000 RPM range at 2 - 5% Throttle opening. This pretty much takes care of this issue.
[MENTION=22326]raduph[/MENTION]

 

[TownsendsFJR1300]

I thought the same but he mentions a "clunk" leaning me towards something mechanical. Perhaps the chain is way too loose allowing much excess slop, but I'd still think the rubber cushions would prevent actual "Clunk".

The Op never did answer what EXACTLY was done to the front sprocket, sprocket nut back when he had issues...

Guess we'll see...

 

[raduph]

Hi,

It does not seem to be a fuel injection problem, as the engine revs without a hitch, it feels mechanical in nature, I can feel the bike shake a bit when it does get the power applied to the rear wheel.
It feels as if the front sprocket starts moving and the rear wheel follows at a tenth of a second or more, I don't know how to better describe it.
Like the slack in the chain snaps into tension and then everything is good, except there is no chain slack... I rechecked a while back and it looks good and I don't want to drop 200$ on a new chain kit.

I've had a friend ride it, he says it feels fine no jerkiness or anything, maybe I'm just imagining it or overthinking it?


Edit: I don't have a central or rear bike stand to get the wheel suspended, it would be much easier if I could film it or something, and the issue seems worse when I have my girlfriend on the back too.
I'm a big guy 103 kgs, together we get the load up to 150kgs, could that be an issue? I keep the rear wheel at 2.9 bar, just thought I'd mention it.

 

[TownsendsFJR1300]

Can you please post what ever was done to the front sprocket previously?

And also, have you pullled off the front sprocket cover and checked the tightness of the sprocket nut, if its even there?

 

[payneib]

I think a rear paddock stand is needed. Get the wheel off the deck, put the bike in gear and see where the slack is. Stands are only dirt cheap off ebay.