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Discussion Starter #1
Posting here because it's a general question. I was out on my 01' 748s today and after some twisties, heading up to a stop sign I took my hands off the bars to get in a little stretch. When I looked down after about 1 second I noticed I had a little bit of head wobble. Not enough to REALLY feel but I've done this move before (not on this road) and never noticed this. It's an S so has a damper. I rode a bit more, and tried again and again, and on many different roads many times if I loosen my grip I'd say 80% chance I start to get a little wobble.

Bike has new tires, forks seem fine...wheel weights are taped over so no issues there. Maybe I'm a bit low on air pressure.

But yeah, I don't know if this is a "take her in" or deal with it type issue. Bike "feels" fine and outside of being slightly off putting no real issues, curious what everyone thinks, and if there is a way to "test" this to see if it's ok or is my bike TOTALLY F'N F'D!!!! :p
 

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Posting here because it's a general question. I was out on my 01' 748s today and after some twisties, heading up to a stop sign I took my hands off the bars to get in a little stretch. When I looked down after about 1 second I noticed I had a little bit of head wobble. Not enough to REALLY feel but I've done this move before (not on this road) and never noticed this. It's an S so has a damper. I rode a bit more, and tried again and again, and on many different roads many times if I loosen my grip I'd say 80% chance I start to get a little wobble.

Bike has new tires, forks seem fine...wheel weights are taped over so no issues there. Maybe I'm a bit low on air pressure.

But yeah, I don't know if this is a "take her in" or deal with it type issue. Bike "feels" fine and outside of being slightly off putting no real issues, curious what everyone thinks, and if there is a way to "test" this to see if it's ok or is my bike TOTALLY F'N F'D!!!! :p
No amount of headshake is normal afaik, it always means something is off... or you are accidentally pulling the front wheel up into the air a lot :laugh:

The list is long, though. Wheels being too low could be all it is... or it could be...

a small dent in the rim
too little rebound (or too much, but usually too little)
stiction in the front axle
forks not quite straight
bent chassis
rear wheel out of line
too much weight on the bars (from the rider) (always stay loose on the bars, but especially during a wobble).
... a bunch of other stuff probably.

I'd say, if the amount of wobble is minimal you are probably OK for now, but you don't want to have that start happening at speed when you need to make a corner... Try re-seating your front wheel first (loosen the pinch bolts and axle but don't remove it, tap the front brake a couple of times to help settle the wheel in the center, re-tighten the axle, then the pinch bolts last. You might need some suspension adjustment though.
 

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Discussion Starter #5
At it's last service, which was about a year ago I got new tires, and had the steering head angle adjusted back to default. So that stuff has been gone over in the last 1000 miles. I like the idea of the rear wheel and potential fork settings. I haven't hit anything so my wheel is ok. The bike came out of 7 year storage last year, perhaps the fork internals are in need of a rebuild.

I have a better street to test on the way to work, whatever it is, if I see it in tomorrows test it's something that is probably "getting worse" I'll update with findings for good data tomorrow

thanks everyone.
 

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At it's last service, which was about a year ago I got new tires, and had the steering head angle adjusted back to default. So that stuff has been gone over in the last 1000 miles. I like the idea of the rear wheel and potential fork settings. I haven't hit anything so my wheel is ok. The bike came out of 7 year storage last year, perhaps the fork internals are in need of a rebuild.

I have a better street to test on the way to work, whatever it is, if I see it in tomorrows test it's something that is probably "getting worse" I'll update with findings for good data tomorrow

thanks everyone.
During that last service when the steering head was futzed with, the service tech may have left something loose or not torqued to spec. I'm thinking about the triple clamps when I say this. If it were me I would go over everything the tech may have touched. Service techs are humans, that said there is a 10% chance something went agoof. I would go over the front and rear axle nut torque, swingin' arm pivot nut torque, triple clamp screws (the ones that tighten the clamps to the fork tubes). There is a small but real chance something was not torqued to spec.

I'm not tellin' ... I'm just sayin'.

:)
 

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Discussion Starter #7
During that last service when the steering head was futzed with, the service tech may have left something loose or not torqued to spec. I'm thinking about the triple clamps when I say this. If it were me I would go over everything the tech may have touched. Service techs are humans, that said there is a 10% chance something went agoof. I would go over the front and rear axle nut torque, swingin' arm pivot nut torque, triple clamp screws (the ones that tighten the clamps to the fork tubes). There is a small but real chance something was not torqued to spec.

I'm not tellin' ... I'm just sayin'.

:)
That's great advice mate, I'll look up that info and take a look If tomorrow shows head shake I'm gonna park her up for a bit while I make sure all is torqued to spec!
 

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The safe answer is never. To add to Wetzel's great troubleshooting list, when was the fork oil changed? If it's the original oil that's a problem. Change the fork oil, adjust the sag and rebound, then do test rides to dial in the compression. Mulholland Drive eats hundreds of bikes, partly because their owners never adjusted their suspension settings: https://www.youtube.com/user/rnickeymouse
 

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Discussion Starter #9
thanks again for more info. Ok, so basically I never noticed it because I have quite a short ride to work, and I'm usually only doing my little stretch in an area where I'm coming to a stop going 20 or so.

Before that I was going around 40 or 50 and did a little test and yeah..............for sure something is up. It's probably been like this for a year.

I don't hunt knee drags and my extreme riding is probably about 60% of what the bike is capable of, which is again probably why I never noticed.

I'll get the tires properly inflated at lunch, then find someone to do my suspension. I've set it back to factory twists, and it feels ass kickingly stiff. I'm sure it needs work, maybe it was sprung for a big Arizona guy!
 

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Discussion Starter #10
Most likely the front tire. Nothing to really worry about in my opinion.
Well I drove into a gas station to put air in the tires. After a tiny ride there, I was (argh can't remember exactly) but something like 27 front, 30 year or something. I did some more tests and for sure, head shake increasing with speed, noticeable around 40 mph hands loose on the bars.

I tried to put some air in the front, and it wouldn't work. So then I had only about 22 in the front, thanks. On the way to the 2nd station, small test and even worse head shake.

Turns out my valve stem internal little clitoris thing is a bit wonky and it's hard to put in air, so it's probably slowly leaking air as well.

I went 30-32 and she rides straight and true again!!!

It should be obvious, but it's REAL important to have the right tire pressures. Probably should be an every morning thing, but needs to be an every fill up thing 500%!
 

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Glad to hear it's the easiest fix! Yes, proper air pressure is vital. Glad you didn't have a blowout or a lowside from running too low pressures.
 
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