Every time I hit a bump, I get the typical FJ loud metallic clunk from the forks. I know it doesn't have any effect on the ride, but it drives me crazy. I'm going to re-do the forks this winter, what do I look for while doing the forks to get rid of the noise?
Kevin.
I don't know that this noise you describe is typical for FJ's.
There are a number of things that could be causing a "clunk" noise when you hit a bump.
Springs that are too soft if you have too little fork oil will bottom and KLUNK!
If the steering bearings are loose, they could clunk. (most likely culprit)
If the fork bearing metals are extremely worn, they could clunk.
Check, grease, and adjust the steering bearings first.
Avoiding the bumps will help too. :-)
Arnie
A weak center-stand spring, will cause the center-stand itself to pull away from the bike momentarily and cause a 'clunk' as it slaps back. Although this may be far enough away from the forks to be eliminated as a culprit.
Worth looking at though.
Dan
That's funny, I did a search and found several references to a noise, clunk etc., coming from the front end. It may not be "typical", but it seems to be "not un-heard of". I don't know how to post a link to another topic, but a search " what the heck is causing that noise" came back with near 2 pages of replies to that one post. There are other refences as well.
The noise only happens when moving and hitting a road crack, or concrete lip like at the entrance to a laneway. I can't seem to duplicate the noise in the garage either. I've tried holding the front brake and rocking the bike to compress the forks, as well as getting it down off the center stand. I've check all the obvious things like instument cluster, tank rubbers, and front fender. All seem to be as they should be.
The head bearings are good, and seem to properly adjusted as there is no play, and the bars move freely from stop to stop with no center notch. I just got the bike this summer, and I do not know if the springs may be worn, what the weight of the fork oil is, or the quantity. The fork seals are a little weak so this is why the I'm going to do the rebuild this winter.
I was just wondering, that while the forks are apart, if anyone else has discovered worn spacers or anything like that.
Kevin
I was hearing a clunk from my front end, same thing... only when moving and hitting bumps. It went away when the back 1/2 of my front fender fell off.... :dash2:
Kevin,
I was getting a similar clunk before rebuilding my forks this spring. It sounded to me like it was coming from the top of the fork tubes. The steering bearings seemed good and I couldn't get any noticeable play when suspending the front end and trying to check for worn bushings or any other looseness. My guess was that it was the 3/4" spacer sitting on top of the springs, maybe getting pushed up against the inside of the fork tube when I hit these sharp bumps. So, when I installed new spacers when rebuilding the forks, I used a larger diameter PVC. (I think it was 1") The clunk has all but disappeared now. I can't be sure if this was the culprit as I added emulators and replaced the bushings also.
I still get the occasional clunk at the center stand that Dan's talking about when I hit a good pot hole or similar. Maybe I should get a new center stand spring...?
Mark
FWIW, my feeling is the forks have worn bushings. I have my stock '89 forks, still with original bushings (about 25,000 mi. on 'em). I found that there is a a small amount of movement between the tubes and lower legs. If the leg is clamped in a vise, the tube will wiggle to 'n fro slightly. My YZF forks have new bushings and no clunk to be found.
Quote from: simi_ed on November 07, 2010, 01:56:47 PM
FWIW, my feeling is the forks have worn bushings. I have my stock '89 forks, still with original bushings (about 25,000 mi. on 'em). I found that there is a a small amount of movement between the tubes and lower legs. If the leg is clamped in a vise, the tube will wiggle to 'n fro slightly. My YZF forks have new bushings and no clunk to be found.
Ed, I still need to get you $ for your clunky forks. Too bad I missed the ride today, the weather was nice and cool, perfect for full leather.
Forks are here, waiting patiently. I missed the ride too. Honey-do list took over ...
Next time!
Ed
Thanks for the input guys. I have to agree with Mark & Ed's suggestions. I swear the noise is right at the top of the forks. And other than fork seals, it wouldn't suprise me if the bushings have never been done. I wasn't planning on emulators, but I may change my mind later. I'm going to change the springs while I'm in there, anyone have any suggestions as to spring rate or manufacturer? I'm waistline challenged, and I drive enthusiastically, so I'm not sure what to change to. Any help would be good.
Kevin
I can highly recomend Traxxon's OMNI springs. I weigh a tad under 200 lbs and the 1.0kg springs are perfect for me..If you decide to replace the fork seals go with the OEM seals, they work best...
http://www.traxxion.com/OmniForkSpringKit.aspx (http://www.traxxion.com/OmniForkSpringKit.aspx)
Hope this helps...
Eric M
I think I read somewhere that the springs can bow slightly in the fork tube during compression and cause a clunking sound on some bumps.
I had a clunk in the fornt end of my '85 that used to annoy me, but for some reason it is now gone.
DavidR.
don't forget to rule out the headlamp reflector.. it can rattle around inside the housing and cause a clunk, too :morning1:
I have the same "clunk"and always assumed the twin Volvo horns crammed in there with very little clearance were hitting the front subframe. I never gave it much thought. However, I have removed the horns and the noise remains. It's not frequent enough to bother me but I would suggest if you have somewhere close by that regularly brings it on, ride over it with your fingertips resting on top of the fork tubes and if they are the problem you'll definitely feel it. I tried this today after reading the posts, with my "noise detecting" (lining removed) helmet on and, of course, couldn't find the right bump.
I'm positive it's in the forks now. I was out for a ride the other night and the air temp was +2 Celsius. The fork oil is really stiff at that temperature, and I noticed the noise was a lot worse and definitly near the top of the forks. I'm thinking more and more it that it's probably the spacers being worn out and banging on the side of the fork tube. I've since talked to the PO and he says that he put progressive springs in, 2 new seals and 15w fork oil. He said that the fork bushings were good at the time so they weren't replaced. I'll know more when Itear it apart after the snow flies. Good point on the "touchy feely" on the fork tubes. It will make the noise on almost any small bump so it will easy try it!
Kevin.
Another possible cause of the knock I was getting was a loose speedo assembly. Mine was loose. I had to add homemade rubber spacers to make it possible to tighten the assembly enough to get it secure. As I remember, the rubber mounts that act as a crush washer we hard and maxed out. Anyway, this is another possible cause as I did this at the same time I did my forks. I'll try to find a picture of the spacers I put in....
Of course I had the front fairing off to get to the assembly---not sure if you were planning to pull the fairing.
However, it would be worth checking the assembly while your there.
Mark
I will be pulling the front fairing, as I need to install an ignition relay for my heated grips and vest. I will also check the speedo assembly as well. It's funny, I could have sworn when I first heard the noise I thought that it was somewhere in the instument cluster. Mark, that would be great if you can find out what spacers and size you put in your forks. A friend of mine does some light maching on the side, and I was thinking of getting new spacers made up to the exact tolerence by him. But if I can use some PVC or something, that would be better. Also, I think I read in one of the posts that you put emulators in. If so, did it make a difference in the handling? My budget is a little tight, but if it's worth it, I might go ahead and put them in. As it is, I'm looking to install a steering damper as well. I had one on my Daytona RD400 (http://www.fastfromthepast.com/servlet/the-1003/Steering-Damper-Stroke%3D115mm-/Detail (http://www.fastfromthepast.com/servlet/the-1003/Steering-Damper-Stroke%3D115mm-/Detail)) and it really smoothed things out in the twisties.
Thanks
Kevin
Quote from: markmartin on November 12, 2010, 11:49:26 AM
Another possible cause of the knock I was getting was a loose speedo assembly. Mine was loose. I had to add homemade rubber spacers to make it possible to tighten the assembly enough to get it secure. As I remember, the rubber mounts that act as a crush washer we hard and maxed out. Anyway, this is another possible cause as I did this at the same time I did my forks. I'll try to find a picture of the spacers I put in....
Of course I had the front fairing off to get to the assembly---not sure if you were planning to pull the fairing.
However, it would be worth checking the assembly while your there.
Mark
No doubt much of the rubber parts of out bikes have seen better days, but if you are talking about the entire instrument cluster, there is supposed to be some play there.... seems counter-intuitive, but true.
Randy T
Indy
Quote from: rktmanfj on November 12, 2010, 04:51:07 PM
Quote from: markmartin on November 12, 2010, 11:49:26 AM
Another possible cause of the knock I was getting was a loose speedo assembly. Mine was loose. I had to add homemade rubber spacers to make it possible to tighten the assembly enough to get it secure. As I remember, the rubber mounts that act as a crush washer we hard and maxed out. Anyway, this is another possible cause as I did this at the same time I did my forks. I'll try to find a picture of the spacers I put in....
Of course I had the front fairing off to get to the assembly---not sure if you were planning to pull the fairing.
However, it would be worth checking the assembly while your there.
Mark
No doubt much of the rubber parts of out bikes have seen better days, but if you are talking about the entire instrument cluster, there is supposed to be some play there.... seems counter-intuitive, but true.
Randy T
Indy
Glad you said that Randy-- I looked for the picture of the rubber spacer that I had installed and found it, but it was on the headlight. My cluster
had been loose, and I tighten it as much as I dared to. As you said, it's supposed to have some play, hence the rubber washers.
My headlight assembly was loose also, (yet
another possible source of the 'clunk') and
that's where I jambed a couple of chunks of rubber behind the top mounting/support bracket. (pic below) The left bracket has the rubber piece (black), and the right has not been installed yet (white). It's the round rubber pieces in the brackets /pinned up on the top of the headlight that had dried up and apparently shrunk, not the speedo assembly. (they were just loose) This did work well to stop the headlight from jiggling.
---This is all further proof that I"m getting to the age where I have to take pictures to remember where I've been!! :wacko2:
(http://fjowners.com/gallery/1/150_12_11_10_5_17_14.jpeg)
Quote from: markmartin on November 12, 2010, 05:44:54 PM
Quote from: rktmanfj on November 12, 2010, 04:51:07 PM
Quote from: markmartin on November 12, 2010, 11:49:26 AM
Another possible cause of the knock I was getting was a loose speedo assembly. Mine was loose. I had to add homemade rubber spacers to make it possible to tighten the assembly enough to get it secure. As I remember, the rubber mounts that act as a crush washer we hard and maxed out. Anyway, this is another possible cause as I did this at the same time I did my forks. I'll try to find a picture of the spacers I put in....
Of course I had the front fairing off to get to the assembly---not sure if you were planning to pull the fairing.
However, it would be worth checking the assembly while your there.
Mark
No doubt much of the rubber parts of out bikes have seen better days, but if you are talking about the entire instrument cluster, there is supposed to be some play there.... seems counter-intuitive, but true.
Randy T
Indy
Glad you said that Randy-- I looked for the picture of the rubber spacer that I had installed and found it, but it was on the headlight. My cluster had been loose, and I tighten it as much as I dared to. As you said, it's supposed to have some play, hence the rubber washers.
I just mentioned it because there have been a few who have shimmed the cluster up solid, and apparently the instruments don't like that very much. :nea:
Randy T
Indy
Quote from: DB Cooper on November 12, 2010, 12:10:28 PM
Mark, that would be great if you can find out what spacers and size you put in your forks. A friend of mine does some light maching on the side, and I was thinking of getting new spacers made up to the exact tolerance by him. But if I can use some PVC or something, that would be better.
Kevin, I'm almost positive that I used a piece of 1" Schedule 40 EMT / PVC tubing. The O.D of this tubing is 1.325" . The O.D. of the forks are 1.625" , I don't know the I.D of the fork tubes, but my guess would be that there about .200 of play. It may be worth finding out what the ID of the fork tubes are and finding the closest fit for available standard Sch. 40 PVC. Someone here must have a fork tube laying around? One other note; the spacer I took out had been cut with a hack saw--fairly square but not perfect and probably prone to 'kick' out and tunk the inside of the fork. The one new one was cut with an electric mitre saw, i.e: perfect 90's.
Quote from: DB Cooper on November 12, 2010, 12:10:28 PM
Also, I think I read in one of the posts that you put emulators in. If so, did it make a difference in the handling? My budget is a little tight, but if it's worth it, I might go ahead and put them in.
As it is, I'm looking to install a steering damper as well. I had one on my Daytona RD400 (http://www.fastfromthepast.com/servlet/the-1003/Steering-Damper-Stroke%3D115mm-/Detail (http://www.fastfromthepast.com/servlet/the-1003/Steering-Damper-Stroke%3D115mm-/Detail)) and it really smoothed things out in the twisties.
Thanks
Kevin
The emulators, for me, are fantastic. I bought the bike with stock springs (I'm assuming they were stock) that were too soft for my liking, so I installed a 1.0 kg springs. These were much better, and if it was only slow speed damping (the fork compressing at a slow rate, not the speed of the bike) they would be adequate. I found that with these stiffer springs, all the little 'quick' bumps and the pot-hole type bumps jolted the forks. This wasn't unbearable, but left room for improvement. Installing the emulators smoothed these right out. The best way I can describe it is it feels like the first inch of travel is alot smoother, and the rest of the travel is very good too. I would defiantly reccommend them--granted they are not free. There are other (cheaper) ways to fiddle with the forks. I just wanted to try these because I'd heard so much good. To add to my 'investment', I replaced the stock shock with a Penske 8900 shock, so it's an all around smoother ride. It has more of a new bike ride now.
Does it handle better?? The ride is smoother and the front wheel feels better planted--better feedback. With exception to washboard pavement in the turns, the 1.0kg springs, no emulators and the stock shock wound up pretty tight, I thought handled well to begin with. Now, with the new suspension, everthing is smoother with no downside, so I would have to say yes, it handles better. (Especially in that 90 degree washboard-ed turn on my way to and from work every day) I'm not a very aggressive rider, so you'll have to talk to someone else for peg-dragging handling info. :unknown:
I'm not familiar with the steering damper you mentioned, but I"m inclined to say spend your money on the emulators first.
Man, this forum is great. The feedback and info is priceless.I'm sure the headlight is OK, but I will check it as well when the fairing is off. I'm also considering an HID light from DDM tuning, so I'll go from there. It's weird how the cluster is loose, but I know it's suppose to be that way. I know someone who tightened thiers up a while back, and now the light bulbs blow out a lot, and now his needles vibrate like crazy. But I'm sure it's the forks, as there is no way the cluster or headlight could make the clunk I'm hearing. I can only describe it as a 1lb ball peen hammer hitting the the top triple tree everytime you hit a bump at low speeds, loud enough to penetrate ear plugs and a full face! If I didn't already check the stem bearings and adjustment, I'd swear that's what the noise is. I'll find out more when I take the front end apart and check from there. I will definitely keep everyone posted and take pictures as to what I find. Thanks for the info and pictures Mark. Really useful info for future use!
Kevin
Quote from: SlowOldGuy on November 07, 2010, 07:15:56 PM
I had a clunk in the fornt end of my '85 that used to annoy me, but for some reason it is now gone.
Maybe need to check hearing aid batteries.... :biggrin:
Quote from: WestOzFJ on November 12, 2010, 10:19:10 PM
Quote from: SlowOldGuy on November 07, 2010, 07:15:56 PM
I had a clunk in the fornt end of my '85 that used to annoy me, but for some reason it is now gone.
Maybe need to check hearing aid batteries.... :biggrin:
Yeah, maybe my ears have notched out that frequency. The test equipment at work is 400Hz. I can't hear a watch alarm anymore (high pitched chirping) because it's in that frequency range that no longer registers. The "wife and kids" notch seems to be growing bigger every day. :-)
DavidR.