Dramatic 70+ MPH

[jager1313]

So i have a 1981 GS 550L that I just got running again. Changed out handle bars in off season to superbike bars, as well as cleaned the carbs.

As I ride to work in the morning, on the highways going 70+ MPH, I can feel the front end wobble a bit. Not really a headshake, or tank slapper, just a slight shaking that makes me a little nervous.

Just wondering if this is pretty normal? The speedometer only goes up to 85, so I feel like I am pushing the limits a little bit. Regardless of this being normal or not, are there any remedies for this?

Always appreciate the help on these questions! Thanks to all in advance!

[bonanzadave]

Tire (air or wear)

Steering head bearings

Wheel bearings

Fork springs / Fork oil

[jager1313]

I know the tires have good pressure, they do look super old though, but not cracked.

How do I check the steering head bearing with out pulling out the whole triple?

I guess i could replace the wheel bearings, just reading about freezing them and dropping it in. I love little tricks like that.

The left fork does seem to have a glazing of oil over it so that could mean its leaking....

The "wobble" dosen't really happen anytime under 65, so its more of a high speed thing. Not normal?

[tkent02]

Not at all normal. If the tires are old replace them.
And 75 is not a high speed thing either, you just have a short speedometer.
Check the rear also, tire, wheel bearings, swingarm bearings, alignment.

[Nessism]

Yup, replace those tires.

You can check steering head bearings by elevating the front end and checking to see if the front end turns smootly. There should not be a detent in the bearings when the wheel is pointing straight, nor any play or binding. Similar for the wheel bearings, check to see if the wheel turns smoothly and the bearings are not binding (you can do with when you change the tires).

Good luck.

[jager1313]

Boo to things that cost money!!!



JK, will change eventually...

[tkent02]

Boo to things that cost money!!!

Like broken bones and crashed motorcycles.
Fix it.

[Nessism]

Go to bikebandit.com and check out the Cheng Shin Hi-Max tires. These tires have a good reputation around here so stay with the Hi-Max. You can get two tires shipped for a little over $100.

http://www.bikebandit.com/tires/c/a642336a637077a5

[jager1313]

Um... What size am I looking for again? Dont have manual with me at work.

Its a 19" front and 18" rear right?

[Nessism]

100/90-19 front and not sure about the back. I think it's a 130/90-16 but you better check to be sure.

[BassCliff]

Not much to add

Hi Mr. jager1313,

Has anybody mentioned wheel balancing? Maybe a weight fell off? You could also loosen up your front end, make sure everything is straight and not binding, then re-tighten.

I'll bet a new set of tires with proper balancing will solve your issues.


Thank you for your indulgence,

BassCliff

[jager1313]

Can anyone post up the specs for the rear wheel?

bikez.com says it 18" but some say its 16"....

[earlfor]

Can anyone post up the specs for the rear wheel?

bikez.com says it 18" but some say its 16"....

Look at the sidewall on your rear tire. The tire size is stamped in on it in 2" high numbers.

Earl

[Nessism]

Depending on the year, the 550L could have used an 18", 17", or 16" rear wheel. In 1981 I'm pretty sure (but not 100%) that it was 16". As Earl said, verify before ordering.

[catbed]

do your tires say MAG MOPUS?