Wobble wobble, dont fall down.

[webbcraft2150]

Head scratcher now. 80g hardbagger w/vetter fairing. New Dunlops Elite II on both ends. New fork oil (15w same as always). Steering head bearings check out good, not loose, not tight. Front fork springs meet specs. Tried different fork air pressure settings and tire pressure settings and rear shock settings. Bike develops a wicked wobble at 95+ and gets worse the faster you go. Fork brace is tight, axle bolts torqued to specs, wheels in perfect alignment. I had this wobble before but figured new tires would make it go away. I also get a slow "weaving" effect on high speed sweepers. I even tried it with the fairing off with no results. What now? New front springs and rear shocks? I used to be able to ride this sucker to speeds that would make me pucker

[gaffer77]

did you get the wheels balanced ??? maybe they arnt balanced properly ,i used to work in a car tyre bay ,youd be amazed at the lack of knowledge and desire some fitters have !!!

also the machines are abused alot so calabration aint great,also tolerence can be adjusted to show good when really is bad!!!

you can do your own balancing but im not going into all that right now

also on the tyre there should be a painted dot which should be inline with the valve ,as this is the heaviest part of the tyre

if it is out of line you need more weight to balance,,,,,, tyres like dunlops are that well made ,,,, with the painted dot in line with the valve ,you should need little weight for balance ,unless the wheel is out of true

bad wheel bearing or shock or something otherwise

let me know if you find out ,mine wobbled violently then i just pulled all the weights off and it was much better!!

id be interested to know other causes as well!!

[ratbyk]

Wobble

Put the bike up on the center stand and give the rear swing arm a good twist side to side. Could be your swing arm bearings are loose. As it moves side to side on it's play the rear wheel is steering the bike back and forth setting up the wobble.
If that checks out OK while on the center stand place a jack under the engine and "just" unload the front tire. Like, barely off the ground. Loosen the triple clamp bolts holding the fork tubes. Standing in front of the bike, place the front wheel between your legs, grasp the handle bars and give a slight twist back and forth the center the wheel with the triple clamp and handle bar. Re-torque the triple clamp to fork tube bolts.
Also, many people who develop a very high speed wobble like you are describing are inducing it themselves by holding onto the handle bars away to tight and inducing the wobble themselves. Try to ride with very "light" hands on the grips.
Ken/Sooke

[webbcraft2150]

wobble..............

The place I got the tires from were very careful when the balanced both wheels. I marked the rims where the weights went just in case I lost one I would know where the went. The "wobble" is more of a side to side one than a vibration a out of balance wheel would cause.

[webbcraft2150]

I never thougt to blame the rear end for the wobble!. Will check that tonight. I have convinced myself to replace the orginal front springs with new ones and replace the 25 year old steering head bearings. I did the wheel bearings just a couple of years ago and checked them when I got the new tires put on. I am not happy with a 95 mph top end!!!!

[strom]

I got something similar here.

1st some history...
a few owners ago, the bike went rather too fast onto a sidewalk.
The result was bent forks and rims, both fixed. So was the gas tank, part of the engine block, I assume exhaust replaced, handlebars welded (!?), one turn signal lens replaced, crash bars...crashed..., Probbably the swingarm too, as it has some new paint...
Dunno about the frame.... feels straight... almost. Looks straight. If I let go of the handlebars, it tends to turn gently to one side... maybe the shaft drive, maybe the frame, maybe the forks....
Anyway, one of my rear shocks was leaking, but I replaced those and the problem is still there.
One of the front forks is leaking more than the other... gonna change them.
Swingarm... got a new one waiting for installation.
Frame... gonna have it checked... one of these days.... maybe...
Anyway, top speed seems to go up with a full tank of gas or a passenger.
Tires are avon venom front and avon roadrunner back. Did that same thing on old michelin M48 and A48.

LP

[Ken Talbot]

If the bike didn't wobble before the new tires, and it does wobble now with the new tires, it has to be something wrong with the new tires or their mounting, or the reinstallation of the wheels. Wheel bearings and swing arms don't tend to fail all of a sudden. or coincidently with the installation of new tires. Put the bike on the centrestand and use a piece of string to see if the wheels are still aligned. You can also try putting a small indicator next to the circumference of each tire as you spin them to see if they are truly round as they have been mounted.

[ratbyk]

Wobble

Another possibility could be one front caliper that is sticking. Just not fully releasing and at those speeds it is causing the front wheel to start a small side to side oscillation that builds in relation to your speed.
Ken/Sooke

[cueball]

Mine had a high speed wobble in the rear when cornering, different shocks with good damping fixed it.

[fxrer]

My 80 SG also had a wobble, over the years, that was most evident at 80+ mph.

I had once hit a curb too hard, and never gave it a thought (or didn't notice). New tires didn't cure it, so I began to check other things. The manual describes a procedure to check wheel "run-out", using a dial gauge. I did this and found a lateral runout (front wheel) that just exceeded the max allowable (2 mm) by a little.

They say that wheels are not serviceable, so I bought one (from a 650) on E-bay for $10, and problem solved! Been running smooth as a gyro ever since.

I guess those wheels are more fragile than they look.

[Geezer]

Look at the seating ring on both sides of both the front and rear tires. The seating ring is a thin little ridge just up from the bead and if the tire is properly mounted it will be the same distance from the rim all the way around.

Also doubble check all the bolts in the front end and the stearing head bearings. If they're dry they'll drag enough to cause problems.

Geezer

[strom]

Originally posted by fxrer
... The manual describes a procedure to check wheel "run-out", using a dial gauge. I did this and found a lateral runout (front wheel) that just exceeded the max allowable (2 mm) by a little.

I got my manual all the way downstairs.... can you describe the procedure?

LP

[fxrer]

Yeah LP and webbcraft,

On page 103 of my Clymers manual, they show a picture of the front wheel, removed from bike, installed on its axle, resting between two blocks. The dial guage is solidly mounted to the jig, with the probe part extended to lightly touch the rim.

As you rotate the wheel, any runout condition will cause the probe of the guage to move in/out. Maximum runout allowed is .08 in, or 2 mm.

This assumes the bearings are OK

[cueball]

There are places down here which can re-roll mag wheels to remove runout or dents, dont cost near as much as new wheels. Should be someone who can do it over there.

[RUSH]

Is this wobble your talking about the same feel as when you drive over a grate bridge? Ive felt that a few times on some grooved roads. My bike has been sitting for a few years and I havent been riding during that time. Is it normal to feel the bike wandering while on grooved pavement? I always felt it on the steel grate bridges.