Bike starts to "wobble" at higher speeds?

[SuzukiGS]

First time out today on the Freeway and at about 60 MPH my bike starts to wobble and seems very unstable.. Anyone know what might be a reason for this?

[80GS1000]

Loose steering stem bearing?

Tire pressure?

When's the last time the swingarm bearings have been serviced and/or replaced?

[bwringer]

Off the top of my head...

- Bad tire(s)

- Steering stem bearings

- Swingarm bearings

- Goofy aerodynamics (usually from a fork-mounted fairing or windshield)

- Bent or damaged frame/wheels/etc.

[chuck hahn]

how fast is "higher speeds" ?

[SuzukiGS]

Where can I check the steering stem barrings? And the Swing arm barrings haven't been touched.. I've only had the bike since November so I don't know anything about it before then.. I have no windshield on it nor a fairing.. How can I check if the Frame/fork/wheels are all good?

And Higher Speeds is about 50 on up..

[chuck hahn]

put the bike up on the center stand and just push and pull the wheel / swimgarm in every concievable direction and listen for any noises. feel for looseness etc etc.. if the center stand has been removed or missing just get the backwheel off the ground without the swingarm sitting on anything..usually a milk crate or such under the engine and tranny will do the prop up job. do the same for the front end.. Jack it up under the motor while it is on the center stand enough to get the front wheel slightly off the ground. get on the bike and grab the bars and shake and twist them around and see if theres any noticeable looseness in the stem bearings In either case dont get so violent as to knock the bike off the stands..I have come close to that a few times.dontknow if it was too strenuous testing or just being real frustrated?? after thought.. while you have each wheel off the ground spin them kinda fast and note if there is any wobble in the rims.... not in the tire itself ..just concentrate on the rim to see if its bent. Next spin it again and look at the tire from behind or head on so to spaek. See if the center tread weaves from side to side.. the rims may be fine but the tire itself may have broken cords and be crap. do this with each rim / tire. And also note any dents, dimples or anything else that may indicated the bike hit a curb or something kinda hard and bent them Thats about all i would check if i was experiencing that wobble.. 50 isnt crap to cause any HIGH SPEED wobble.. in my opinion anyways.

[bwringer]

How old are your tires?

Search "tire date codes" for lotsa info.

[chuck hahn]

to enhance what bwringer added the DOT code is found in an oval embossed on the side wall,of the tire it should have 4 numbers in it. These numbers tell what week and year the tire was manufactured. For example:: if the number in the OVAL is 0178 that would mean the tire was manufactured during the FIRST week of 1978 so that would mean roughly January 1-7 of 1978..get it?

[Theo]

to enhance what bwringer added the DOT code is found in an oval embossed on the side wall,of the tire it should have 4 numbers in it. These numbers tell what week and year the tire was manufactured. For example:: if the number in the OVAL is 0178 that would mean the tire was manufactured during the FIRST week of 1978 so that would mean roughly January 1-7 of 1978..get it?

Actually, if a tire had 4 digits after the DOT, it would have been produced with in the last decade. All tires before 1999 or 2000 used 3 digit tire codes. So a tire produced the first week of 1978 would be written as 018. But the 8 could mean any decade ending in 8. That's probably why they changed the standard in 2000.

[Big T]

As far as bent/alignment issues go, Use a string and duct tape

Put bike on center stand
Tape string to one side at front of front wheel low enough too clear frame/exhaust/etc
Run string to rear wheel at same height, pull tight, tape to both sides of tire
Run string up the other side of the bike as above and pull tight, Attach to front tire

Set front tire so string is equidistant at rear of tire (measure it)

Now, measure the distance at the front of the rear tire to compare. This should also be equidistant. If not, rear tire needs to be reset with chain adjusters and measure again

If bent, no amount of tweaking will keep both front and rear equidistant

[steve murdoch]

A couple other things to check.
Equal fork oil amounts and/or pressure.
Improperly aligned wheels.

[chuck hahn]

Theo... this is why i love this forum. The 4 didgit was expained to me some time ago but noone had mentioned the three digits or that there was any other system.. thanks for expanding my knowledge and i suspect others as well..thanks, chuck.

[Theo]

As far as bent/alignment issues go, Use a string and duct tape

Put bike on center stand
Tape string to one side at front of front wheel low enough too clear frame/exhaust/etc
Run string to rear wheel at same height, pull tight, tape to both sides of tire
Run string up the other side of the bike as above and pull tight, Attach to front tire

Set front tire so string is equidistant at rear of tire (measure it)

Now, measure the distance at the front of the rear tire to compare. This should also be equidistant. If not, rear tire needs to be reset with chain adjusters and measure again

If bent, no amount of tweaking will keep both front and rear equidistant

Just posting a site that has good visuals of what Big T is talking about.

http://www.motorcyclemetal.com/downloads/Harley%20Davidson%20Wheel%20Alignment%20Made%20Simple.pdf

Ignore the fact it's for a harley. It's all the same.

[bonanzadave]

good visuals of what Big T is talking about.
http://www.motorcyclemetal.com/downl...e%20Simple.pdf

This shows some HDs might have wheel offset from 8-13mm. Do our GSs have any offset ? Last time I checked mine with 2 straight edges I think I had a little offset.

[Theo]

This shows some HDs might have wheel offset from 8-13mm. Do our GSs have any offset ? Last time I checked mine with 2 straight edges I think I had a little offset.

Truth be told I have no idea. I was just posting it for the pictures of how to set up the string.