Page 1 of 1
Rear chatter
Posted: Thu May 14, 2009 6:39 am
by BarraSpalding
so its done it since i've owned it, but something can't be right.
when I down shift at a high rpm n get the compression lock-up/slowing of the rear wheel... it chatters/boucnes/jumps like fkn crazy instead of sliding.
anyone else experienced this? solution? (i suspect its something to do with the rear suspension - and yes I do blip da throttle to match revs n such... but if/when the rear wheel does lock, the wheel should slide not chatter along the ground IMO)
Re: Rear chatter
Posted: Thu May 14, 2009 6:49 am
by the kid
Oh , I thought this was a post about Gos
Re: Rear chatter
Posted: Thu May 14, 2009 7:43 am
by dave#3
With most of your weight forward and the bike's weight transferring forward (momentum) there's going to be fuck all weight over the rear end and it's likely to skip about (as you describe). I guess you could soften the rear end up enough so that it didn't exhibit this behaviour, but I think it would be a compromise that would shit you 99% of the time when you weren't compression locking the rear end. My advice would be to use the brakes to slow the bike down (they're much more efficient at doing so and less prone to failure) and avoid locking the rear end alltogether. If you really like to band down through the gears get a newer bike with a slipper clutch or fit an aftermarket ramp-style slipper clutch to your bike ($1500 from memory).
Re: Rear chatter
Posted: Thu May 14, 2009 7:54 am
by Jonno
BarraSpalding wrote:so its done it since i've owned it, but something can't be right.
when I down shift at a high rpm n get the compression lock-up/slowing of the rear wheel... it chatters/boucnes/jumps like fkn crazy instead of sliding.
anyone else experienced this? solution? (i suspect its something to do with the rear suspension - and yes I do blip da throttle to match revs n such... but if/when the rear wheel does lock, the wheel should slide not chatter along the ground IMO)
Probably dampening adjustment to slow the shock rebound response a little?
The following is a direct cut'n'paste from one of my handy suspension worksheets. By no means am I an expert.
TOO MUCH REBOUND DAMPING (REAR SHOCK)
This creates an uneven ride. The rear suspension compliance is poor and the "feel" is vague. Traction is poor over bumps during hard acceleration (due to lack of suspension compliance). The bike wants to run wide in corners since the rear end is "packing down"; this forces a nose-high chassis attitude, which slows down steering. The rear end wants to hop and skip when the throttle is chopped during aggressive corner entries.
- The rear "jumps" on the bumps instead of following the surface.
- The rear "jitters" under braking.
- It holds the rear down with the result that the bike will understeer!
- It can cause overheating in the hydraulic system of the shock
absorber and make it fade, in other words, it will loose damping
when hot
Symptoms:
Ride is harsh, suspension control is limited and traction is lost.
Rear end will pack in, forcing the bike wide in corners, due to rear squat. It will slow steering because front end is riding high.
When rear end packs in, tyres generally will overheat and will skip over bumps.
When chopping throttle, rear end will tend to skip or hop on entries.
Solution:
Too much rebound. Decrease rebound "gradually" until harsh ride is gone and traction is regained. Decrease rebound to keep rear end from packing.
HTH
If you want the full worksheets PM me and I will send them too you.
the kid wrote:Oh , I thought this was a post about Gos
Thats what I thought
Re: Rear chatter
Posted: Thu May 14, 2009 8:02 am
by BarraSpalding
Cheers jonno... I will get to looking at that rebound.
Have you got a link to those worksheets? or something that can help explain how to adjust my rear suspension... with pretty pictures hopefully!
Re: Rear chatter
Posted: Thu May 14, 2009 8:36 am
by Jonno
BarraSpalding wrote:Cheers jonno... I will get to looking at that rebound.
Have you got a link to those worksheets? or something that can help explain how to adjust my rear suspension... with pretty pictures hopefully!
The link to these was gone some time ago, luckily I saved them.
Maybe i should do a new post or find a free host somewhere as I cant upload to the public forum.
PM me with your email addy mate, I have them on file
Re: Rear chatter
Posted: Thu May 14, 2009 2:47 pm
by photomike666
Sounds like something to post and be made into ta sticky to me!
Re: Rear chatter
Posted: Thu May 14, 2009 3:26 pm
by Wattie
most of the noisy you would hear while skippign a rear wheel would come from the chain slapping back and forth aswell.
not good for longevity.
the backlash would go right back through the gearbox. mmmmm nice
Re: Rear chatter
Posted: Thu May 14, 2009 5:56 pm
by Rossi
Too soft FRONT - diving under brakes loosening the rear contact patch ??
Re: Rear chatter
Posted: Thu May 14, 2009 7:42 pm
by Strika
Can you fill me in one some more details about what ZX6R it is and what suspension you have..ie aftermarket or standard? This will somewhat determine my suggestions.
Re: Rear chatter
Posted: Thu May 14, 2009 7:46 pm
by Wattie
Rossi wrote:Too soft FRONT - diving under brakes loosening the rear contact patch ??
you could have a solid front (pushbike) and still be getting the rear end light.
it cant be stopped.
only way to soften the chattering is a slipper clutch
Re: Rear chatter
Posted: Thu May 14, 2009 9:00 pm
by Rossi
Wattie wrote:Rossi wrote:Too soft FRONT - diving under brakes loosening the rear contact patch ??
you could have a solid front (pushbike) and still be getting the rear end light.
it cant be stopped.
only way to soften the chattering is a slipper clutch
I'm too old to argue
Re: Rear chatter
Posted: Fri May 15, 2009 5:58 am
by BarraSpalding
Strika wrote:Can you fill me in one some more details about what ZX6R it is and what suspension you have..ie aftermarket or standard? This will somewhat determine my suggestions.
02' ZX6r... 636... stock as a rock suspension wise... need to get my suspension actually set-up for ME... xcept there is fkn no company I know of to go to in townsville.. damn fkn hick cuntryville shit
Re: Rear chatter
Posted: Fri May 15, 2009 8:30 am
by Strika
OK, that makes things really simple. I doubt very much it has anything at all to do with suspension set-up. With that model ZX6, you could crank every setting to Max, and it would still handle OK. Standard they have fuck all real damping. I would guesstimate, that it is your technique causing the rear end chatter. I know you said you are matching revs, but it can also be caused by being too aggressive with the controls....Gears, Rear brakes! Try smoothing out your down changes, clutch actuation and rear brake pressure. I think you will find things smooth out nicely!
Re: Rear chatter
Posted: Fri May 15, 2009 10:04 am
by BarraSpalding
Yeah i had a comment from another forum (yes i'm a whore) and it was put to me that I should smoothly feed the clutch out instead of dropping it... like I have been.
either way I do need to get my suspension setup for me... ie. sag and the like... but moreso I just need to be a better rider i guess. nah fuck that... ITS THE BIKES FAULT!!!!!!!!!