weaving

[SOREASS]

I'm looking at a 1992 R100GS PD, and on the test ride found it to work very well except for a bad weaving. The seller,[who I don't know] who is a motorcycle mechanic, and really impressed me with his knowledge and his passion of motorcycles, said he had recently replaced the steering head bearings and they needed adjustment. After loosening them a little the bike weaved much less but, still, noticably especially at low speeds. The steering felt very light and quick, maybe unnaturally so, however I am not used to this particular model so I'm not sure about that.
I ended up not buying the bike because I wasn't sure of the possible cause. I worry about possible bent forks, but there are probably a lot of other things it could be like worn shocks, etc. The tires were dual purpose in good shape. The front and back wheels appeared to line up and he said he had checked them with some sort of laser tester. BTW, mileage showing on the bike is 73,000 km's.

Any thoughts. Thanks

 

[20774]

Yeah, there can be a lot of things to consider in tracking down a weaving situation. I would tend to first suspect the steering stem bearings as they were just replaced. My tests for the correct tigthness is to see how fast the handlebars fall from the center position to one side or the other. If they fall quickly and literally bounce off the stops, that's too tight. If you nudge the bars one direction and they just stay where you pushed them, they're too tight. You want something in between.

The mechanic was right, they usually need adjustment as they bed in. So after some miles, it's reasonable to expect to go back and recheck the tightness.

 

[ebeeby]

I had a similar experience and a little loosening fixed it.

 

[Rapid_Roy]

Yeah, there can be a lot of things to consider in tracking down a weaving situation. I would tend to first suspect the steering stem bearings as they were just replaced. My tests for the correct tigthness is to see how fast the handlebars fall from the center position to one side or the other. If they fall quickly and literally bounce off the stops, that's too loose. If you nudge the bars one direction and they just stay where you pushed them, they're too tight. You want something in between.

The mechanic was right, they usually need adjustment as they bed in. So after some miles, it's reasonable to expect to go back and recheck the tightness.

Corrected slightly.

 

[20774]

Corrected slightly.

Just a bit...+1...isn't there an editor on this site that catches those things!

 

[g rad]

I'm attempting to adjust my 93 R100 GSPD head set bearings, for the first time. The locking set up very tight nut, plus a inner thread through it... I've never seen similar setup on other airheads.. 22mm 1/2 socket + strong arm,, not able to loosen.. any feed back much appreciated,, Impact wrench next? screen shot

 

[20774]

Pretty old thread! You should probably try a good penetrant on those threads...something like AeroKroil or PBBlaster. Give it time to soak. Also get some fluid where the nut contacts the yoke...let it soak there too. Use a 6-point socket or wrench. I think using an impact wrench will provide quick shocks to the nut/threads which can help loosen things. A wrench with a cheater bar and lots of pressure sometimes can be a recipe for disaster...especially if the wrench slips.

So what condition are you trying to fix? Is it some weaving? Can you describe what is actually happening? Did you do the static tests identified in post #2 above?

weaving

I'm looking at a 1992 R100GS PD, and on the test ride found it to work very well except for a bad weaving. The seller,[who I don't know] who is a motorcycle mechanic, and really impressed me with his knowledge and his passion of motorcycles, said he had recently replaced the steering head...

forums.bmwmoa.org

 

[stevenrankin]

The top lock nut I believe is torqued to 150 ft/lbs, tight. An impact wrench will work or as mentioned a cheater bar. The big thing is to have a very good socket with a good fit. Cranking hard on a poor socket can cause it to slip off or not quite fit and damage the nut.

Oh, beside the impact wrench and cheater bar, try tapping with a dead blow hammer on the wrench in the direction to loosen. St.

 

[AntonLargiader]

That steering head bearing system (also used on the later K bikes) is fully described on my website. It is, IMO, a really good system. Should not be tighter than 65 Nm and you will want to thoroughly clean the parts so the threads move freely.

I realize the OP has long since made up his mind about that bike, but the weaving he mentioned can be related to the tires, specifically on the R100GS.

 

[stevenrankin]

Opps, I forgot we are dealing with a German bike, Newton meters, instead of foot pounds, LOL, Hi Anton, how are you? St.