Chatter under power

[1cyl]

How you doing folks. Just got in from another pit bike sm session and got a bit of an issue.....

When coming out of a corner and putting the power on. The rear end starts to chatter/hop and begin to brake traction into a bit of a slide. It's not the wheel or tyre because I've recently changed both and problem still remains. So about to focus on the rear shock. Although its a piggy backed, its a cheapy one, the only adjustment I can make is preload/sag. Is this likely to yield any results? What about gas? Thinking of just junking it and buying a fully adjustable. (And spend the summer trying to figure out how to get it to work for me... Fail miserably and end up paying someone who knows what they are doing....and while he/shes at it get the smc done as well. Although no matter what knobs I twiddle on that, it always feels as planted and steady as a great oak!)

Cheers

Slim
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Chase my Witch up, Catch my Snitch up.
The SMC | The Pit | Stable

[Blue_SV650S]

Sounds like it is under damped, no fiddling with the spring preload or sag will sort this.

New shock I am afraid.
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The purpose of life is to fight maturity.

[stinkwheel]

I'd agree. Sounds like a damping problem. If a pitbike is chattering the rear under power, do you have any damping at all? When you push down on the back of the bike with no rider on, does it bounce more than once?

That said. Setting your sag is a good first step, if your spring rate is good, it'll compensate for a lot.

The damping on my VFR failed entirely the other weekend (as in shim stack coming off the damper rod levels of fail leaving me with just a spring). I was getting rear end chatter and skipping under heavy power (like wire tight and doing over 9,000rpm on a nominally 100bhp motorcycle) but the bike was still rideable at speed on some pretty rough and twisty roads as long as I wasn't too ham-fisted with the throttle. Pretty happy with that because it means my spring size and sag adjustment must be pretty much bang-on if it wasn't topping or bottoming out all the time.

You have less power and pro-rata more suspension travel so the damping would need to be really bad to cause that kind of problem. Maybe it's leaked the air out or something (which would cause a loss of damping over the first part of the travel)?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[1cyl]

Cheers folks. Have increased preload to 7mm static sag 25mm rider sag. Will see how it feels on the blacktop when I next get a chance. If its worse ill decrease back the other way(although surely that's in the offroad direction?) if that fails I might get gas checked but more likely to just spurt this.

https://bit.ly/10v8Mqs

Or this

https://bit.ly/184yzIm
____________________
Chase my Witch up, Catch my Snitch up.
The SMC | The Pit | Stable

[1cyl]

You were both right. On the nail stinkwheel When I arse slammed the back of the seat it bounced up and down about 3 times while squeaking before settling + now I've swapped it, I pushed the valve just to see and found bugger all pressure behind it!.

£140 Fully adj DNM arrived today, slapped it on and bounced on the seat: instant return and no squeaks! Took it straight out without even touching a dial......

Feels like its on a rail now. Shaved a whole 1.2secs off my SM lap record within the first 5 laps!
Can't wait to try it in dirt.

Now gonna spend time setting sag and then begin fine tuning to find my perfect SM and Dirt clicks.
____________________
Chase my Witch up, Catch my Snitch up.
The SMC | The Pit | Stable

[Zen Dog]