I have this wobble that happens if I am not holding bars tight or let go one hand. This is typically apparent at lower speeds, around 35-40 Mph and lower. As soon as I put the other hand back on the grip it stops. This is intermittent and doesn't happen every time I am in that speed range. At highway speeds the bike is rock solid stable.
How abnormal is this? My front tire is kinda worn. Could it have something to do with that? What else can it be?
shouldn't happen at all
my old girl is rock steady, I can coast no hands (not a recommendation) for ages until the speed drops off.
if you're up for a new tyre, get the new tyre and a good balance and see if it stops.
Maybe get the back balanced at the same time.
could be aero related, in a certain cross wind, buffetting. But this would only be if you have some non std things poking out into the airstream i would imagine
Check again after you put a new front tire on. If you still have the issue then consider steering stem bearings, front wheel bearings. Heck, try increasing your front tire pressure to see if that makes a change, could give you a hint if the front tire is the cause. Just don't use tire pressure to fix your problem, keep the tire pressure set properly for the safest riding...
Quote from: Rhino on May 25, 2013, 09:14:33 PM
shouldn't happen at all
my old girl is rock steady, I can coast no hands (not a recommendation) for ages until the speed drops off.
That's what I figure. Might have something to do with us having lots of grooved concrete pavement around here, too. I've noticed some rubber likes to follow it more than others.
I have a new Shinko on order at a local shop (guy quoted me $2 over what it would cost shipped form an online dealer, I'd rather feed a local). We'll see what happens.
Is it worthwhile replacing the bearings while I have the wheel off, or am I better leaving well enough alone?
Quote from: JPaganel on May 25, 2013, 09:21:17 PM
Is it worthwhile replacing the bearings while I have the wheel off, or am I better leaving well enough alone?
What do you know about the bearings? Have they ever been exposed to a pressure washer? With the bike in the center-stand and enough weight on the rear seat to lift the front wheel, how does it feel when you spin it?
Quote from: FJmonkey on May 25, 2013, 09:27:13 PM
What do you know about the bearings?
These specific ones on this bike? Not a thing.
Quote from: FJmonkey on May 25, 2013, 09:27:13 PMHave they ever been exposed to a pressure washer?
No idea.
Quote from: FJmonkey on May 25, 2013, 09:27:13 PMWith the bike in the center-stand and enough weight to lift the front wheel, how dies it feel when you spin it?
Dunno. Will go try that.
Got the bike up on the centerstand and got a kid to sit on the rear fairing. Children make handy counterweights. :yes:
Wiggled fork and wheel everywhich way and couldn't detect any signs of play. Spun the wheel. Didn't see any irregularities in the tire, but I know that doesn't mean anything.
The only anomaly was a rubbing sound that I think is from a spot on the left brake rotor. Maybe it's warped a little?
Other than that, looks normal.
I have the same thing at around 60 km/h (so pretty much the same speed). I suspect it tire related. I've had it before on my '86 and now again on my '92 and in both cases have checked all the other usual culprits, leaving the front tire as the most plausible cause. I'm running the Avon Storm ST tires on my bike. When I get to Vancouver this summer (en route to Alaska) I am going to put a fresh set of Michelin Pilot Road 3's on it and we'll see what happens. In my case, it tends to get worse as the front tire begins to cup. Maybe it even has something to do with riding most of the time in SW Ontario where the roads are flat and straight!
Good luck. I will be interested to see what you determine is the cause.
Zwartie
Check the tire first. Inflation pressure as well as wear. If it's all good, stick the bike on the centerstand and see if you can detect play in the steering (sit down in front of the bike and pull the wheel fore/aft). Try the bounce test as well; with the front in the air, you should be able to nudge the bars and have the steering go smoothly through its range of travel and hit the stop without binding, bouncing off, or doing anything else funky.
Other things you can check if everything looks otherwise okay is making sure the forks are straight and the wheels are aligned properly with each other.
Some tires tend to do it more than others. Particularly tires with a more sporting intent, as they often have a more triangular profile and a bit less stability in a straight line. Sure do feel nice when you're midcorner though...
While the wheel is off, it's a good time to not only play with the bearings, but also pull the forks entirely off, give them a bath, and put some fancyfresh oil in them, as well as some new valving, appropriate springs, additional preload spacers, seals, bushings, dust caps, or whatever else fits your desire & budget. You can also raise the forks through the triple clamps a bit if you'd like quicker steering, but there's only ~5mm or so of room before you hit the master cylinders. If you pull the forks, take the time to take a good look at the brake lines also, especially if they're rubber and possibly original.
Quote from: andyb on May 26, 2013, 08:29:13 AM
You can also raise the forks through the triple clamps a bit if you'd like quicker steering, but there's only ~5mm or so of room before you hit the master cylinders.
I got nearly 20mm out of mine before they hit the M/C.
(http://farm9.staticflickr.com/8560/8841452997_f1ed445096_z.jpg)
My masters are apparently at a much different angle than yours :)
Quote from: andyb on May 26, 2013, 08:29:13 AM
Check the tire first. Inflation pressure as well as wear. If it's all good, stick the bike on the centerstand and see if you can detect play in the steering (sit down in front of the bike and pull the wheel fore/aft). Try the bounce test as well; with the front in the air, you should be able to nudge the bars and have the steering go smoothly through its range of travel and hit the stop without binding, bouncing off, or doing anything else funky.
Done that. Tire is worn, but looks true. I'm not really trusting that, though, as I've had car tires that look just fine do weird things at speed.
The rest of the stuff is okay - there is no play I can feel anywhere and all movement is smooth. Well, except that one spot on the brake rotor. It's weird there is a noise there, I'd have thought the brakes would pulse if there were things wrong with it.
Quote from: andyb on May 26, 2013, 08:29:13 AM
Other things you can check if everything looks otherwise okay is making sure the forks are straight and the wheels are aligned properly with each other.
Besides just looking, how would I check that?
Quote from: andyb on May 26, 2013, 08:29:13 AM
While the wheel is off, it's a good time to not only play with the bearings, but also pull the forks entirely off, give them a bath, and put some fancyfresh oil in them, as well as some new valving, appropriate springs, additional preload spacers, seals, bushings, dust caps, or whatever else fits your desire & budget. You can also raise the forks through the triple clamps a bit if you'd like quicker steering, but there's only ~5mm or so of room before you hit the master cylinders. If you pull the forks, take the time to take a good look at the brake lines also, especially if they're rubber and possibly original.
Were the budget there, I'd rebuild this bike to mint. :dash1:
The suspension doesn't seem bad to me, it's pretty firm and diving under braking is not what I'd consider excessive. I was planning on keeping the forks as is until I can get a set of post-91 ones with the larger wheel and better brakes.
And I know all about brake lines. My other bike (which is being expropriated by the Mrs.) is a 1978 XS400, which had the original 1977 brake hoses. You could feel them swell like balloons if you touched them while hitting the brakes. They also deteriorated on the inside and the rubber bits that flaked off plugged some tiny passages in the rear MC, necessitating a full rebuild.
So I replaced them with that red stuff you see here:
(http://i285.photobucket.com/albums/ll41/JPaganel/Vehicles/XS400/IMG_20130524_195631_zps868544c5.jpg) (http://s285.photobucket.com/user/JPaganel/media/Vehicles/XS400/IMG_20130524_195631_zps868544c5.jpg.html)
That's Teflon-lined, stainless steel braided, vinyl coated brake hose with stainless fittings. I got that custom made at Pirtek, an industrial hydraulic hose supplier. It was actually slightly cheaper than OEM hose. Those hoses have close to zero expansion and make brakes just awesome. Also, they oughta last near forever.
I'm planning a set of those for the FJ at some point.
My 85 has an occasionall wobble :shok:
front tire is almost slick but im sure the wobble is from the steering head bearings.If I brake hard I can feel some movement in them.There loose.Repack and retighten the nuts if there still good replace if there not.
I am puting on a new tire as well as some maintenance at the same time.I will ride another bike while I do the work.
I need a steering head wrench first as I dont have one.
Quote from: Flying Scotsman on May 26, 2013, 10:21:09 PM
My 85 has an occasionall wobble :shok:
front tire is almost slick but im sure the wobble is from the steering head bearings.If I brake hard I can feel some movement in them.There loose.Repack and retighten the nuts if there still good replace if there not.
I am puting on a new tire as well as some maintenance at the same time.I will ride another bike while I do the work.
I need a steering head wrench first as I dont have one.
The castellated nut shouldn't be on very tight. The adjustment is pretty light. Here is one I made using a nut as a pattern and 4 pieces of key way stock from Ace Hardware.
(http://fjowners.com/gallery/2/1651_15_07_11_9_11_19.jpeg)
(http://fjowners.com/gallery/2/1651_15_07_11_9_09_01.jpeg)
The socket is a 27mm
George
I will not over tighten it.
Only recently started to do it and only when hands are of the bars.
I would just snug it up but im sure it needs new grease after all its 28 years old.
Quote from: Flying Scotsman on May 26, 2013, 11:06:03 PM
I will not over tighten it.
Only recently started to do it and only when hands are of the bars.
I would just snug it up but im sure it needs new grease after all its 28 years old.
That's all I did to mine. The tool I made is mostly handy for using a TQ wrench (inch lb) on it. I TQ'd mine to spec and I didn't like the way it felt so I went "old school".
Wheel in the center tightened up until it didn't "tip" over on it's own weight and then loosend it up to where she just bairly "falls" under her own weight. Hard to explain, I was taught this method many years ago from an old timer. Now I am old........ :dash2: Not saying it's the right way, just my way.
George
Quote from: movenon on May 26, 2013, 11:23:00 PM
That's all I did to mine. The tool I made is mostly handy for using a TQ wrench (inch lb) on it. I TQ'd mine to spec and I didn't like the way it felt so I went "old school".
Wheel in the center tightened up until it didn't "tip" over on it's own weight and then loosend it up to where she just bairly "falls" under her own weight. Hard to explain, I was taught this method many years ago from an old timer. Now I am old........ :dash2: Not saying it's the right way, just my way.
George
I agree George, I use a variation on theme. Same as tapered wheel bearings. Tighten up until there's no play and back off a whisker. Feel gives a better result than trying to apply a specification to it.
The grease they use in there gets very hard over the years and unlike most bearings, they don't spin and spend most of there life in the one position.
Removing, washing out and re-greasing these is an excellent idea if it hasn't been done for a while.
Noel
Quote from: Flying Scotsman on May 26, 2013, 11:06:03 PM
I would just snug it up but im sure it needs new grease after all its 28 years old.
I wouldn't even bother adjusting it if the grease is original. It's worth the trouble to take them out and wash them.
Quote from: andyb on May 26, 2013, 10:25:03 AM
My masters are apparently at a much different angle than yours :)
It's been a while since I had mine off, but isn't there a location pin?
My 89 did this until I set the static sag to 30mm front and 25mm rear. Static sag is the amount the suspension compresses under the weight of the motorcycle and rider. All it takes is some time and some spacers!
Race-Tech's website has lots of good info.
http://racetech.com/page/id/30#3 (http://racetech.com/page/id/30#3)
Q: What is "Race Sag" (Static Sag)?
A: Static Sag or Race Sag is the amount the bike compresses from fully extended, with the rider on board.
Here's how to measure it.
1.First extend the forks or shock completely and measure from the wiper to the bottom of the triple clamp on forks or from the axle to a vertical reference point on the chassis. This is L1.
2.Take the bike off the stand, put the rider on board in riding position. Get an assistant to balance the bike or have the rider hold onto something, compress the suspension about 25mm (1") and let it extend very slowly (slowly is the critical term). Where it stops, measure the distance between the wiper and the bottom of the triple clamp or the axle and the reference point on the chassis again. Do not bounce. This is L2. (If there were no friction in the seals the bike would come up a little further.)
3.Next lift up on the suspension and let it drop very slowly. Where it stops measure again. Do not bounce. This is L3. The reason L2 and L3 are different is due to stiction or drag in the seals and bushings. (If there were no friction in the seals or the linkage the bike would drop a little further.)
4.Half way between L1 and L2 is where it would come to rest with no friction. Therefore L2 and L3 must be averaged and subtracted from L1 to calculate true Static Sag.
Static Sag = L1 - (L3 L2)/2
5.To adjust Static Sag make longer or shorter preload spacers or use the preload adjusters, if available.
It is important to note that there are no magic Sag numbers. However here are some guidelines to use as starting points. Please refer to the DVS Valving Search for specific guidelines.
Bike Type Front % Front (mm) Rear % Rear (mm) Rear Free Sag (mm)
Dirt Bikes (>300mm travel) 22-25% 65-75 30-35% 95-110 25-50
Dirt 80cc Minis 22-25% 55-65 30-35% 75-105 20-40
Street Bikes 28-33% 30-35 28-35% 28-37 2-17
Road Race Bikes 23-27% 25-30 23-30% 23-32 2-17
I had a wobbly effie once, checked all the usual suspects, no takers, rode again but didn't do it, hmmmm odd, what did I change, ,soon worked it out, when it wobbled I had a big bag of shopping on the back,,what had happend was a mount had snapped on the rear rack, causing the weight to become unstable and wobble
So, the new tire at proper pressure made for a much better ride, but I still got the wobble once in a while.
I sucked it up and bought the fork brace from RPM. I'm pretty sure the wobble is cured now.