wobbling at high speed

[kurt112345]

I have a 81 gs1100 stock 16v and when i ride on the free say 70-80 mph and i change lanes and say hit a small bump my steering goes back and forth quickly does the same thing at about 100mph going straight starts wobbling. any thoughts i checked first to make sure the bearings where tight in the steering.

[bobthebiker88]

do you have a notch worn in your steering bearings? get the front off the ground an feel it, it should move perfectly smoothly from left to right, lock to lock.

also, how are your tires? are they worn, or cupped? tire pressure? rear wheel aligned properly?

there are a LOT of possible causes.

[Mindless]

Low pressure in the tyres, incorrectly set up suspension front and back (too soft), rear wheel misaligned.

Could be due to many things, but I'd start with checking the above.

[bobthebiker88]

an out of round wheel, or one that is not true, especially spoked rims, will do this. my 84 XT 600 was like that, and it took everything in my power to keep it in 3 lanes at 70mph. had the front wheel respoked and trued up, she tracked PERFECTLY down one lane at 75-80ish.

just something to think about.

[posplayr]

I have no idea what you have done to your bike if anything , and since you mention nothing I would assume nothing. That being the case

1.) check tire pressure and date codes to make sure they are not more that 3-4 years old.

2.) replace oil in forks , increase preload; as the the springs are likey shot

3.) Set the steering head tension while you have the front off the ground.

4.) Increase the preload in the rear as crappy worn out shocks will probably limit the stability due to rear end wallowing.

5.) check brakes for sure.

You can go around the block, but do this before getting on the highway at any speeds for sure.

From there you can keep going down the list(see Mindless's start but there are plenty of lists here I'm sure) and improvements will increase the speed you can go.

This the basic bare minimum I did to my 81 GS750E to feel comfortable at even 65 mph.

If you plan on going 100 mph, get some:
progressive springs up front ($60)
newer shocks in the rear ($250 progressives)
Avon Road Riders and pump them up to 40'ish lbs as per ratings ($200). The high tire pressure reduce side wall flex and improves stability.

and wear a full face helmet to go with your $500 insurance policy.

For myself, I would do no less than that.

[argonsagas]

You have a number of good replies, so I will add something else:



If you know you have a problem at 70/80 mph, then why would you run to 100? You are flirting with extreme danger.

STAY AWAY from high speeds until you get this repaired.

[posplayr]

You have a number of good replies, so I will add something else:



If you know you have a problem at 70/80 mph, then why would you run to 100? You are flirting with extreme danger.

STAY AWAY from high speeds until you get this repaired.

Yes, instability once it starts tends to build until the motorcycle lays down (one way or another). At a given speed you can get into a low level wobble or weave, but it can just get worse.

[bonanzadave]

Speed wobble alert .......

argonsagas make a wise statement.

Speed is an addiction. Go get help .

[bonanzadave]

Avon Road Riders and pump them up to 40'ish lbs as per ratings

OK. Im gonna try that. Im running the front at 32 and the back at 34.

Let me run something else by you. I put a dial caliper on my rear wheel. +- .002-.003. Pretty damn true. Then I moved it to my rear sprocket. +- .025. I can see it wobble. Is there any way that the plastic insert, inside the wheel where the sprocket hub fits, could be worn ? Bent rear sprocket ? Stiff chain link causing flex ?