Had a fantastic albiet tiring 300km back-country solo tour yesterday. As i'm upgrading bits and pieces, other bits and pieces show their weakness. Its my 2nd week on my 91 fj12 and i'm getting more and more comfortable with each ride. Yesterday on the twisties i was really noticing the wobble in the corners.
What is the cause of that? is it shock linkage or the yamaha oem shock itself? my tire pressure is spot on. Tires are new (battleaxe's). not even riding aggressively compared to a more experienced rider.
is the wobble actually dangerous or is just an annoyance?
Had a bmw shock on route but apparently it got lost in transit, the company came good immediate and reimbursed me (well done!!!). While i would prefer an RPM plug and play shock i'm too cheap at the moment...so i'm hunting another bmw shock down now.
Don
Don, congrats on the new FJ. I just bought a 92 myself. Great bike so far after about 250 miles. Your wobble could be coming from the front or rear suspensions. The front could be loose/worn steering head bearings, clapped out fork oil or just the soft front suspension. The stock legs have a lot of initial dive on braking and can cause a weave or wobble mid-corner especially over any bumps. I found there are preload adjustments for the forks but stiffening up mine hasn't done much to help. The rear shock can cause the same symptoms if rebound damping is weak. Haven't done any mods to mine yet but a suspension upgrades from RPM are right at the top of the list along with brake upgrades. hth
George
But is it dangerous or is it used as an indicator of 'don't go any faster'?
I
My first and cheapest option will be to drain the existing Fork oil and possibly get new springs...or valves. Not sure which is better bang for buck.
Then the BMW shock/new doglegs.
As I was dialing in my rear shock I expereinced a rear waggle when accelerating out of corners until I got the rebound damping cranked up enough. A few more clicks of rebound damping tamed everything down.
Quote from: Easterntide on May 12, 2014, 07:37:40 AMYesterday on the twisties i was really noticing the wobble in the corners.
What is the cause of that? is it shock linkage or the yamaha oem shock itself? my tire pressure is spot on. Tires are new (battleaxe's). not even riding aggressively compared to a more experienced rider. is the wobble actually dangerous or is just an annoyance?
Don
Don,
Are the tires balanced? Put the bike up on the centerstand.
Rotate the rear tire slowly and watch where the tire meets the rim. There is a line on the tire, very close to the rim. If this line wanders away from the rim someplace, the tire could be mounted slightly off-center in one spot, giving a "bulge" there.
Put a screwdriver on something solid (concrete block, brick, et c.) very close to the rim, and rotate the tire rapidly. With the screwdriver tip very close to the rim, you will see if the rim is bent.
Grab the top and bottom of the rear wheel and apply some side forces, to see if the swingarm has any play or looseness.
Raise the front wheel. Check the front tire for a mounting "bulge" as you did on the rear tire.
Check the front rim for any bends, with the screwdriver trick.
Turn the handlebars from side to side. Check for any excess looseness, and for any "notchiness" or "detents" in the steering.
Put the wheels on the ground. Sit on the bike, hold the front brake firmly, and see if the bike frame can be moved forward and back, causing the steering head bearings to wobble up and down.
Beyond these checks, then maybe it is time for fork maintenance, or a new rear shock, but check the other stuff first.
While you are making improvements, consider adding a front fork brace. This is not a fix for any problems found, but it is usually an improvement, even on a good stock set-up.
If the steering head bearings are bad, you
could replace them with tapered bearings, making a big improvement there for little extra cost.
I would consider a wobble in turns as dangerous, and definitely worth fixing.
Cheers,
Red
Quote from: Easterntide on May 12, 2014, 07:37:40 AM
Had a fantastic albiet tiring 300km back-country solo tour yesterday. As i'm upgrading bits and pieces, other bits and pieces show their weakness. Its my 2nd week on my 91 fj12 and i'm getting more and more comfortable with each ride. Yesterday on the twisties i was really noticing the wobble in the corners.
What is the cause of that? is it shock linkage or the yamaha oem shock itself? my tire pressure is spot on. Tires are new (battleaxe's). not even riding aggressively compared to a more experienced rider.
is the wobble actually dangerous or is just an annoyance?
Had a bmw shock on route but apparently it got lost in transit, the company came good immediate and reimbursed me (well done!!!). While i would prefer an RPM plug and play shock i'm too cheap at the moment...so i'm hunting another bmw shock down now.
Don
Don,
I tried an R1200RS shock on my 1990 FJ. I mounted it up, built new dogbones to get my rear ride height about 1" higher than stock. I found the spring rate marginal for one up riding I was (210 lbs. geared up at the time) and completely unrideable 2 up. It ground the midpipe on a V&H pipe at nearly any lean angle. I will sell you the shock, without the hydraulic preload adjuster, (I am using it on the Honda Goldwing GL 1800 shock that I currently have on the bike). If you are very light, it may work for you, I didn't work for me.
Also, check out the items the other guys have mentioned. Even with the ragged out rear OEM shock, I experienced very little wobbling in corners, just some pogoing.
Joe
Locally a person is selling a BMW f650gs from a 2000 model year. Good value if it would work.
Going to follow Joes advice and hunt now for late model GL1800 rear shock. fingers crossed and all that....
About ten years ago I had a similar thing with a 90. At highway speed it would gently rock back and forth. It seemed as though the pivot point of the rocking was above my head. Weirdest thing I have ever experienced on a bike. Long sweepers at high speed, 120 - 160 k range. Never got worse. I just thought it was my tires. Check swing arm and suspension linkage bearings as well. Many people ride around with pooched swing arm bearings.
johnnie,
That sounds like the behavior of many of the motorcycles of the 60s and 70s. Bombing through high speed sweepers would bring out a low frequency, high amplitude weave. Felt like there was a hinge in the frame of the bike between the seat and gas tank. I'll never forget the first time I experienced it, I was on my Dad's Suzuki GS 750. His Triumph Bonneville would do it on occasion as well.
My FJ has never hinted at doing the weave, I would be checking out all the things that have already been mentioned.
Joe
So.
Fork seals ordered and new headset bearings. i've pushed and pulled on the rear wheel while on center stand and could not perceive any movement. Tire pressure is correct and tires are mounted straight and true.
Also have a new GL1800 shock on its way.
will push pull on the front wheel elevated tonight just cause.... hoping its as simple as a loose front end.
Taking it to a local mech for the bearings/seals and will get him to give it a look though at that time as well.
Had the bike on the center stand last night to install SS clutch cable. after pushing it off the center stand i felt a significant thud up front. put it back up and checked ..sure enough the front end had fore/aft play that was due to a loose steering adjustment. As I've said I've got the new bits on order (early next week) but in the meantime i may see if i can snug up the existing bearings.
I've downloaded the microfiche showing the parts but are there any specifics i need to know about making adjustments and what tools are needed to tighten up the lock nuts?
tried doing a search for steering and bearings but nothing much came up...
Amazing how much just tightening the steering bearings makes it feel like a completely new ride!!!
F'n hell! It's hard to know what's wrong if it's a new thing and particularly if your doing this all solo. Thankfully lots of cats here are kind enough to step in and add value.
Much happier person tonight :-)
:good:
Quote from: Easterntide on May 23, 2014, 04:23:39 PMAmazing how much just tightening the steering bearings makes it feel like a completely new ride!!!
F'n hell! It's hard to know what's wrong if it's a new thing and particularly if your doing this all solo. Thankfully lots of cats here are kind enough to step in and add value.
Much happier person tonight :-)
Easterntide,
At least the fix is in sight, and it will get there soon. Now, this next part is really tough . . . I doubt that the steering head just got somewhat unscrewed lately. It is more likely that a few of the bearings got shattered, and the pieces are still close by, looking to make trouble. You have the good parts coming, so the best plan for now is to
stay off the bike, until the steering head is cleaned out and the repairs are made. Even a small metal chip in there can lock the steering, and that never ends well. You can bet big on this issue, but the payout will be very small, and to me, it's just not worth the risk. Live to ride another day. All IMHO, of course.
Cheers,
Red
New taper bearing headset and new fork seals are now at my home.
this weekend will be putting seals in the forks and getting that sorted.
then if that makes me feel good inside i'll attack the bearings in the steerer!
Q: does the fairing have to be removed for the bearing races to go in? Or do you just need to remove the forks and then the steerer will drop out after all else is disassembled?
i can do that on my bicycles w my eyes closed...but they don't have fairings :-)
You don't NEED to remove the fairing, but it is safer to do so.
After the fork tubes have been removed and all the hardware from the top triple, the lower triple and steering stem will drop out. (make sure you've removed the brake splitter from the lower triple)
Then, you can learn the difficulty and frustration of removing the bearing cups from the steering tube.
There are a few different methods you can use - search the files here.
The "Park" tool may work for you, if you have one.
Enjoy your weekend :-)
I wussed out and didn't do them but my fork seals are done. Bike feels great at the moment. My local bike shop (bicycle) has all the park tools and I can borrow them as needed.
Maybe on the next rainy weekend.
Now waiting on my springs and valves from rpm/new to me Corbin and gl1800 shock to land :-)
I was having a bit of a cornering wobble - more of an uncertainty than anything major - tendency to follow rough bits in the tarmac, etc, in my FJ 3CV I've not had it for that long and generally it has been well cared for. Rear shock was a bit sad anyway so I replaced it but the main issue was the dogbone bolts - I took everything off, including the swinging arm, to regrease them to find that they all were a bit loose and the one nearest the back wheel wasn't much more than finger tight. So if you're having this kind of wobble/tracking issue, have a look at them. In fact, have a look at them anyway! Cheers, And.
Quote from: Easterntide on May 12, 2014, 03:13:19 PM
But is it dangerous or is it used as an indicator of 'don't go any faster'?
I
My first and cheapest option will be to drain the existing Fork oil and possibly get new springs...or valves. Not sure which is better bang for buck.
Then the BMW shock/new doglegs.
bang for the buck: springs
If you are going to change the head stem bearing, be sure to have a good supply of swear words ready. They do not like coming out.
I had good luck using this type of cut off wheel on a Dremel tool to cut and remove the lower race. Carefully make two cuts through the bottom race and it will come right out with little effort. They are readily available at Home Depot among other places. 1-1/4 in. x.063 in.
(http://fjowners.com/gallery/6/150_11_01_14_9_42_45_0.jpeg)
I used the Park removal tool that I bought from Randy to get the top race out. The trick to using this tool is to slowly pull it down through the stem from the top until the spring steel fingers 'snap' open under the race. The bottom of the tool will be sticking out of the stem and you can just hammer it up and the upper race will come out.
My initial mistake was that I started by inserting the Park removal tool up the stem from the bottom, not realizing that there is another lip right below the upper race. After much pounding and no progress, I shined a flashlight up the stem to reveal the error of my ways. Luckily I didn't break anything.
If you don't already know, the Park removal tool will not work on the lower race---the bottom race is set into a step that is slightly larger in diameter than the rest of the bore--there is no lip revealed for the tool to grab.
Getting the correct amount of torque on the stem nut bearing is the tricky part. I seem to have gotten it right but after 5000 miles, I've noticed that I get a slight wobble when I let go of the bars -- it appears that I need to tighten it up just a smidgen more.
As a quick disclaimer to start, I don't like starting new threads where old ones are (or seem) relevant.. :morning1:
Anyway, after all my shenanigans with new clutch (which is great) my attention turned to why my 1990 FJ1200 didn't feel right turning into corners. I'm no road racer, but even I like to lean a bit when the road is clear and the sun is shining..
So I thought, before splashing out on new progressive springs I'll change the fork oil - which I did yesterday. All was going well as I undid the first fork cap (carefully..) and so I started on the other one. Once this was removed I noticed a small problem. Some numbnuts had put different..... yes that's right DIFFERENT springs in each fork. On the plus side (if there is one) both were progressive springs but one was approximately 5-6cm longer than the other with markedly different gauge metal and 'looser' coils.
All of which explained why one side had been more difficult to adjust the preload and why my bike felt awful turning into bends. So I changed the oil anyway, put it back together and await my new springs. When I fit the new springs I'll try and take a couple of photos of what was in there, just for fun. :bomb:
I've tried to give previous owners the benefit of the doubt, but sadly to my mind, all roads lead to a lazy bodge, which to me is unforgiveable considering how much we rely on the front end of our bikes. Not clever. :dash2:
On the plus side, I'll have a bike that inspires a bit more confidence soon, which I look forward to.. :good2:
Shocking that a P.O. installed two different rate springs in the front end...will be worlds better when you get that sorted. :good2:
In a *slight* defense of "previous owners"...All while growing up, my dad was known to say, "If you want it done right...do it yourself!!" Turns out this is not at all accurate. The saying should be, "If you want it done the way YOU want it done, do it yourself!" It's a very important distinction. In your case, the PO had NO business rebuilding forks. On the other hand, in some cases, decisions were made by PO's without your knowledge of the circumstances at that moment.
I once re-tapped a bottom bracket on a French bicycle for a guy who was touring across the U.S. The proper tap and bearing cups were NOT available anywhere to keep him moving on his journey. After a long discussion with him, he told me to go for it and tap it to accept metric bearing cups. I cringed a bit, but did it in the interest of his journey. I also wrote a note explaining the circumstances and shoved it into the bottom bracket before re-assembly. Sort of an apology and explanation to the next mechanic who discovers this and exclaims, "What was that guy thinking???" :pardon:
Quote from: Capn Ron on May 02, 2015, 04:32:02 AM
Shocking that a P.O. installed two different rate springs in the front end...will be worlds better when you get that sorted. :good2:
You are quite right Capn about the difference it will make but one could be equally shocked at a PO adding a second clutch spring to hide a worn out clutch from a prospective buyer.
If I found a bike with a second spring added to hide a knackered clutch, I would not be happy. I would wonder what else he tried to conceal.
Noel
Quote from: Capn Ron on May 02, 2015, 04:32:02 AM
...I also wrote a note explaining the circumstances and shoved it into the bottom bracket before re-assembly. Sort of an apology and explanation to the next mechanic who discovers this and exclaims, "What was that guy thinking???"
Great foresight and bloody good mechanic manners there. Nice one. :good2:
Just reminded me of this same bike...earlier on in my ownership while trying to find the reason for a front end bars wobble (on slowing down) I found a couple of loose nuts on one of the yokes, which didn't inspire confidence at the time...in the end, as it happens a new tyre sorted the problem. Guess we all bodge from time to time and it has to be said some bodges are ok and sometimes even ingenious at times! :yes:
It does make you wonder though..
I'm currently waiting for an rpm shock to be built for my bike.
I have a BMW rear shock on my bike with dog bones that I'd be willing to sell you.
I'm located in ontario so shoot me a private message.
Rob
Quote from: mark1969 on May 02, 2015, 04:04:53 AMI'll try and take a couple of photos of what was in there, just for fun. :bomb:
Old springs..Ok, I exaggerated. The difference is about 3-4cm, but still..
(http://i892.photobucket.com/albums/ac121/markandrew1969/IMG_20150513_192626_zpsxak5tuwe.jpg) (http://s892.photobucket.com/user/markandrew1969/media/IMG_20150513_192626_zpsxak5tuwe.jpg.html)
New springs - lovely.
(http://i892.photobucket.com/albums/ac121/markandrew1969/IMG_20150512_172944_zpshn5ysmpm.jpg) (http://s892.photobucket.com/user/markandrew1969/media/IMG_20150512_172944_zpshn5ysmpm.jpg.html)
Quote from: mark1969 on May 02, 2015, 04:04:53 AM...all roads lead to a lazy bodge, which to me is unforgiveable considering how much we rely on the front end of our bikes. Not clever.
And the reason I think it was deliberate? The preload adjusters were set completely differently (which I had forgotten) presumably in an attempt to counter the different spring lengths... :bomb:
It is more common than you think to run different springs in each fork leg, In fact on my bike (SV1000S) I am running a 9.0 in the left leg and 9.5 in the right.
Basically I found that the 9.0 spring allowed too much movement unless I adjusted the valving to stiff for comfort. The 9.5 transmitted too much energy. I run a 9.5/1.0 combination in my track YZF600.
There are even bikes out there that only have damping in one leg! I owned a 1996 KTM 440MXC that had a marzocci fork that had compression in one leg and rebound in the other.
Keep in mind that the forks are connected by the front axle, a light duty fork brace, the lower and upper triples. There is very little deflection if the bushings are in good shape. If you are experiencing chassis wobble with an otherwise stock FJ I would look very closely at all chassis bearing, especially steering head, swing arm and wheel. If all of those check out my next target would be to ensure that there is sufficient damping in the shocks. Any of these can cause chassis wobbles even on a rock stable bike like the FJ.
It has been my experience that many chassis issues that a rider feels are in the fork can easily be traced to the rear of the bike, Keep in mind that the swing arm and main frame are both essentially big tuning forks attached to the little bits you hang on to.
I'm not aware that people normally have 2 different springs in their forks.
I must be riding the bike wrong then. I know, I'll check everywhere else on the bike just to see if that is affecting my front end handling.
That's where I've been going wrong. Thanks for pointing it out.
Next time my lights don't work I'll check the tyre pressures. :crazy: :wacko1: :dash2: :dash2: :good2:
Quote from: mark1969 on May 14, 2015, 04:34:33 PM
I'm not aware that people normally have 2 different springs in their forks.
I must be riding the bike wrong then. I know, I'll check everywhere else on the bike just to see if that is affecting my front end handling.
That's where I've been going wrong. Thanks for pointing it out.
Next time my lights don't work I'll check the tyre pressures. :crazy: :wacko1: :dash2: :dash2: :good2:
Might as well check the blinker fluid while you are in that deep...
Hey guess what? My bike handles much better with 2 equal springs in the front forks. It's no race replica, and would be better with some RPM fork valves and springs, but it's a lot more predictable and actually leans into bends properly without feeling awful like it did..
:good2:
Quote from: mark1969 on May 17, 2015, 01:46:17 PM
Hey guess what? My bike handles much better with 2 equal springs in the front forks. It's no race replica, and would be better with some RPM fork valves and springs, but it's a lot more predictable and actually leans into bends properly without feeling awful like it did..
:good2:
Very good to hear that your FJ is performing as expected, or at least better and not causing concern in the corners. Other fork upgrades will also give noticeable improvements. It can be addicting to make just one more improvement....