Shimmy

[bemusedinsojo]

Today, I was hauling a@s down the freeway when traffic got all bunched up so I slowed down, then a strange thing happened-the steamer started to shimmy quite a bit. It stayed that way until about 50 mph then smoothed out until I exited the off-ramp at which time it shimmied all the way home. The slower the wigglier. I checked the air pressure last night at 42 psi according to the tire. I'm not sure what else to look for and it scared the daylights out of me so I won't be riding until it's fixed.

What should I look to fix? Maybe my head?

[ssevy]

Maybe lost a stick on wheel weight?

[tonytiger]

Like ssevy said cousing a bit wheel wobble

[Timbox2]

Check spokes too

[tankerman]

Or wheel bearings?

[JayDub]

Wheel bearings, steering bearings, swingarm, tyres 

[bemusedinsojo]

I put it up on the center stand and shook both wheels and forks. There is no play, however the front wheel bearings appear the have seepage so they will need replacing. How do I check the swing arm? I'll look for a lost wheel weight.

[Nick Calne]

The swingarm can crack around the clamp.

[bemusedinsojo]

The swingarm can crack around the clamp.

Dear god I hope not. I ordered parts to stop the sprocket cover leak so I will look for a cracked swing arm (oh crap, oh crap). There appears to be no lost wheel weight, and the spokes are tight. What I failed to mention was the rear tire was mounted but not aligned so it wore funny. I aligned it according to the manual Last May and still have it on, but it looks terrible. The outer tread is still good, while the inner tread is cupped (or worn irregularly). I ordered a Full Bore 150/70/17 today because that is the one that is on now-not stock but it works.

If the swing arm cracks around the clamps can it be welded or does it need a new one? Are the clamps at the rear where it gets loosened to adjust the chain?
Thanks for all the suggestions.

[London_Phil]

Before we go throwing swingarms etc, at it, I would, as it seems you've already done, ensure tyres (dont start me with the spelling...) tyre pressures, headstock etc all responding as normal. 42psi seems high to me, are they road tyres? were you two up?
There are some frame possibilities, the rear subframe can crack if heavily laden, and a few have had fractures around headstock, usually as a result of previous crashing, but these are rare issues.
Did this come on suddenly?, is your shock ok?, and are your front forks even, and have they been recently checked for fluid level.
Rear suspension link lubed recently?
Seems like a lot, but a methodical check of the bikes integrity, is a good starting point.
I would give it a basic safety check, ensuring its mechanically as you would expect,  then take it for a gentle ride.
Does sound like that rear tyres not helping.
Tyre Tyre Tyre....

[bemusedinsojo]

The funny thing to me is that out of all our language differences, tyre is always surprising to me as I guess the US spelling is shocking to those who spell it with a "y." Same thing, round rubberish thing needed to make the ride more comfortable more comfortable. Is it retyred when you are too old to work then?

Anyway, I was alone when it started to shimmy so no extra weight. The tires are full bore 80/20 dual sport tires. I put 42 psi because that is what is stamped on the sidewall-I go high because I'm 300 lbs. I have never lubed it so I will get on that. I haven't checked fork oil so that too will get done. As for the rear-I thought I saw a leak in the reservoir but I cleaned off whatever it was and haven't seen anything since so I'm guessing it is ok for now.

Since I am trying to stop a significant oil leak now, I noticed the chain rub block was down to metal (not the swing arm one). Maybe that is part of the problem. Will I need a new chain because of the metal on metal? Anyway, I'll get working on everything and report back.

If I don't get too tyred 

[Sin_Tiger]

The pressure marking on the casing (technical name for the round black things) is generally the maximum recommended pressure. I personally wouldn't go above 2.7 bar (39 psi) cold. For weight you adjust the pre load on the rear spring to suit the load rather than adjust the pressure. I'd suggest reading up on static and dynamic sag to help you understand things a bit better.

[bemusedinsojo]

The pressure marking on the casing (technical name for the round black things) is generally the maximum recommended pressure. I personally wouldn't go above 2.7 bar (39 psi) cold. For weight you adjust the pre load on the rear spring to suit the load rather than adjust the pressure. I'd suggest reading up on static and dynamic sag to help you understand things a bit better.

Will do. Though at my age I know a little about sag.

[ssevy]

Before we go throwing swingarms etc, at it, I would, as it seems you've already done, ensure tyres (dont start me with the spelling...) tyre pressures, headstock etc all responding as normal. 42psi seems high to me, are they road tyres? were you two up?
There are some frame possibilities, the rear subframe can crack if heavily laden, and a few have had fractures around headstock, usually as a result of previous crashing, but these are rare issues.
Did this come on suddenly?, is your shock ok?, and are your front forks even, and have they been recently checked for fluid level.
Rear suspension link lubed recently?
Seems like a lot, but a methodical check of the bikes integrity, is a good starting point.
I would give it a basic safety check, ensuring its mechanically as you would expect,  then take it for a gentle ride.
Does sound like that rear tyres not helping.
Tyre Tyre Tyre....

Bullshyt, bullshyt, bullshyt

(See now why the y doesn't werk :icon_wink:)

[Sin_Tiger]

Bullshyt, bullshyt, bullshyt

(See now why the y doesn't werk :icon_wink:)

Try it with a Glaswegian and I think you'll find it works just fine