Why wobbling while leaned over?

[3moskvichi]

Why would my steering wobble while leaned over?

My 88R100RT runs great while straight up and down, smooth as can be. When leaned over beyond about 10 degrees though, I can feel a slight wobble in the handlebars, as if the front wheel were unbalanced. I know the front is balanced, and the tire is fairly new, though one size larger than stock (100 vs 90). At highway speeds while riding normally there's no bounce. I have a single Koni shock on the rear, which while old, seems to be in good condition, and new progressive springs up front. The wobble doesn't seem to be coming from the rear, and the wheels are true. It's somewhat unnerving while leaned over to feel that wobble. What's going on?

 

[3moskvichi]

one more thing

I also had new steering head bearings installed, so that should not be the issue.

 

[crazydrummerdude]

Yer frame straight?

 

[mymindsok]

Wobbles that appear to be in the front end are frequently caused by something amiss in the rear end.

Just a few weeks ago, I was riding my R-90 (Rebuilt/restored everything.) and felt the bike wobbling in the turns and under braking. It felt like the front end was out of shape but as it turned out , the swing arm was a little loose and needed a reset.

If your shock has some miles on it, I'd call it a suspect but check everything and report back.

 

[3moskvichi]

swingarm?

I guess I'm showing my ignorance, but I didn't know you could even adjust the swingarm. How would you do that?

 

[88bmwjeff]

Clymers, Haynes, or a search online should show you how to center the swing arm in the frame.

Also, how many miles are on your bike? My 88 R100 RT needed the swing arm bearings replaced, and the final drive needed re-shimming when I had it rebuilt. I don't know if any of these could cause a wobble, but it can't hurt to checked for proper operation.

With regards to final drive needing re-shimming, if you grab the rear wheel and move it back and forth (kind of a left/right movement while looking down on the bike) there should be little no movement. I hope I explained this well.

 

[mymindsok]

Do yourself a favor and buy a couple of shop manuals that address Airheads. A Clymer and a Hayne's are a good start.

Then sit down and read them from cover to cover. Having a basic understanding of how your bike works, will be a big help to you.

 

[jforgo]

You don't mention if you have a trunk. If you do, and have weight in it, that could cause an issue.
I would also check the steering head bearings yourself - no telling what someone else did...

 

[3moskvichi]

clymers

Yep, my Clymers does address the issue. It just scares me though, since it's mixed in with the section on the driveshaft, and talk about special tools, one-time use special nuts, and such.

As for mileage on m RT, Jeff, it's at 71K, and I can guarantee the swingarm bearings haven't been touched since day 1, since I'm the original owner.

 

[LOSTBOY]

A rear tire which has worn flat in the center can cause this symptom. Try keeping your body more upright, which will tilt the bike farther. If the weaving disappears, you have found the source by getting the tire away from it's transistion from flat to curved. If this is the case, it's time for a new rear tire

 

[PeoriaMac]

It just scares me though, since it's mixed in with the section on the driveshaft, and talk about special tools, one-time use special nuts, and such.

Well, the special socket is just a 27 mm from Sears, ground down a little. The special clutch centering tool looks much like a pencil...and some have used one for the same effect. (no no, I know--I actually bought one as well) So, if you've got some airhead riding friends they might be have some of this stuff in their tool kit. Or there's always the Airhead Tech Day....or if you should "help" really loud...someone might ride over to do just that.

Mac

 

[RandyB]

Snowbum has the answers. Wear your shades.

I would:

Tighten the sub frame bolts.

Retighten the steering head bearings.

Check the swing arm bearings for wear and ensure the arm is centered.


Do you have a heavily loaded top box?

And for the oddest fix of all: When you counter steer, do you push with the arm leading into the turn or pull with the opposite arm? Pushing makes things smoother.

 

[mymindsok]

Yep, my Clymers does address the issue. It just scares me though, since it's mixed in with the section on the driveshaft, and talk about special tools, one-time use special nuts, and such.

As for mileage on m RT, Jeff, it's at 71K, and I can guarantee the swingarm bearings haven't been touched since day 1, since I'm the original owner.

Yikes!

After reading you answer, I'm almost afraid to ask what else hasnt been touched on your bike but here are some suggestions:

1) Lube the stering head bearings, the swing arm bearings, all of your bikes splines and make absolutely sure that everything gets torqued to factory spec.

2) while youre doing these tasks, have some knowledgable Airhead check the bearings and races to see if they need replacing.

3) check out your shocks and if theyre tired, replace them.

4) look at your forks checking the fluid levels and the health of the internals. referbish as necessary.

It's not like you have to do this stuff every season but it sounds like your bike needs a through going over before it bites back.