Author Topic: Help, rear-end squirmy (or just a dream)? (Read 3518 times)

Dundee · « **on:** January 08, 2007, 03:57:02 AM »

Guys I'm hoping someone can help me out. Background - last week, joining the freeway in the wet I got a lovely big slide on (just before I'd reattached my TPS), in a straight line no less. I'm actually pretty proud that it didn't faze or surprise me at all (it was THIS big), but; now when I give it some out of a corner, or even a sharp junction turn-off, I feel like the rear is rolling around a little. Tyre's fine, axle nut present

, could this maybe be my shock? I'm heavy, lots of kays on it, and I haven't had it rebuilt or set up for my weight.

Am I just imagining this? I ask because many years ago I got caught in a rip, and lying in bed that night I could absolutely feel the water pushing and pulling my legs

I'm wondering if it's just the same thing.

aussiebandit · « **Reply #1 on:** January 08, 2007, 06:05:02 AM »

I'll leave this the the experts, but when you say the tyres are fine, did you check the pressure? I've found, on previous bikes, that if the presssure is too low, and I mean too low, the back end (or front end) can do some pretty weird and scary things. Hence why I'm a bit anul on tyre pressures now....

You don't say exactly how old your bike is, but it could be worth doing some basic tests or setup of the rear suspension - you know 'static sag' etc see http://www.bikepoint.com.au/portal/alias__bikepointau/tabID__5766/BikeTipType__Setup/DesktopDefault.aspx

ZenMan · « **Reply #2 on:** January 08, 2007, 11:20:03 AM »

Yes, definitely check your tire pressure first. If that's ok, then get it up on the stand and check for any looseness or play in the axle or swing-arm. If the wheel bearings and swing-arm bearings/bushings are good, then start looking for cracks or breaks in the frame.

One quick test is with the bike off the stand and the tires on the ground, grab the rear sub-frame under the seat and wiggle it hard left-to-right. There shouldn't be any looseness or wobble at all.

Good luck.

pmackie · « **Reply #3 on:** January 08, 2007, 01:14:29 PM »

I addition to the above comments, a bad, or badly worn, rear shock can give this sensation. Try increasing the rebound damping to the max.

Does the rear shock feel bouncy at rest? Any signs of oil leaks from the shock?

And as funny as it sounds, check the steering head bearings. Put the bike up on the centre stand and shake the front forks. If you feel any loosness in the steering head area, adjust the bearing tension.

Ranger · « **Reply #4 on:** January 08, 2007, 10:02:31 PM »

smooth operator · « **Reply #5 on:** January 09, 2007, 08:58:07 PM »

Yes what they said, tyre peasure 1st. But a good shock makes a world of difference. I couldn't even set my sag where I wanted it with my stock shock.(25-30mm)
Have you checked your sag and adjusted it? Sport Rider has a good thread on setting sag. I have a mark on my subframe plumb from the axel for measuring my sag. I have it set up pretty good now.Tracks like a champ.

Rocketjock · « **Reply #6 on:** January 10, 2007, 11:53:36 AM »

Nobody brought up alignment. It may be something a body shop has to do but maybe it's worth checking out. Has it ever been crashed? I know I bought a Triumph once that seemed OK but pulling the tank revealed a definate bend in the frame.

Dundee · « **Reply #7 on:** January 10, 2007, 07:24:34 PM »

guys, I'm offended! I'm the tyre pressure nazi! "no leaks for you".

All very helpful advice guys, but my pressures are always spot-on (in fact I'd done the Putty run days earlier, aussies will know 500+k's winding road). Head bearings are fine (adjusted 2000km ago), of couse I did check the swingarm for play but nothing there. There wasn't any visible signs of trouble on the shock either. Ranger, the tyre hasn't cooked either.

I'd never bothered with the rear sag though. Maybe this should spur me into action.

Remember guys, this came after a sideways moment at about 120 kmh. I haven't noticed it since, so I'm basically putting it down to psychology.

Thanks for the great response.

interfuse · « **Reply #8 on:** January 15, 2007, 09:42:21 AM »

If it was a one time deal you might have just hit something slippery. Wet spot, painted arrow, patch of oil, road kill, etc...

Blade · « **Reply #9 on:** February 13, 2007, 12:44:15 AM »

Quote from: "Ranger"

I had the same thing happen to me while back. I called this guy that makes parts for Bandits...Oh wait, different thread

After looking at everything on the backend, all fasteners tight (look at the dogbone connectors), nothing lose or wiggling, I was sittin there staring right at the problem...Too many heat cycles on the rear tire!
Take alook at yours to see if it's got a nice green/blue'ish tint on the sides and across the tread. Just for kicks, I pulled out a can of starter fluid (don't do this with the garage door closed or around open flame/sparks, wiped down the tire and went for a quick spin. Yup, the tire was planted for about 3 blocks and then the squirlyness started back in.
Just to prove a point, I pulled the rear wheel off and put on my spare rear wheel with a BT014 that had one trackday but only a couple heat cycles; it stuck like glue and there was no twitchyness even on the painted crosswalk stripes.

To further prove the point, I bought new tires and haven't looked back.

Usually on a Bandit, I will check the front end first for pressure or cupping, but in my case, it was the heat cycles...The tires get whats called a "greasy" feeling.

+1, but make sure to check everything