XH Motorcycles Forum
Motorcycle Resource Forums => Technical Resource Discussion => Topic started by: brixtonanimal on November 25, 2019, 09:59:27 PM
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I am experiencing a significant wobble on deceleration, almost turning into a violent speed wobble. Is this the result of a loose steering head bearing? At what point do they need to be replaced (only if notchy)? If this is the culprit any help in the tightening procedure would be great, I found the FSM to be a bit vague without pictures
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Some of us call it the death wobble..... It's not really a death wobble, but I suppose if let alone, it could be a real safety issue.
Some of our bikes do it on acceleration. Some on decel, and other just coasting in neutral.
The top bearing isn't exactly the correct design for what it's being used.
Jamie/Marti have come up with an update that works very well..
OEM is a flat cut bearing, that cannot get the "load". Jamie's is a beveled bearing with a matching race.
I'm replying via my phone, so I don't have the torque spec at hand, but I believe it's 30 pounds. The torque number is on this site in the downloads.
I strongly suggest getting Jamies update, I've put one in and it works very well. It's my.personel project this winter on my bike.
I don't know your skill level of wrenching, but this is a bit in-depth. Please ask, and I'll provide all info needed.
I have edited this from its original date...
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Had the same death wobble a few years ago on my way back from a long trip, talk about a white knuckle ride!
Mine was so loose that I could feel it by holding the front brake and gently rocking the bike forward and back.
I jacked the bike up by the frame allowing the front wheel to just touch the ground, then removed the upper clamp and retorqued the lock nut. It's important to find that happy spot between too loose, which will cause a wobble, and too tight which will cause bearing wear, binding, and a host of other issues including "reduced vehicle control resulting in personal injury."
As I recall it took a large wrench (1", 1 1/4"?) and the work was in close proximity to the tank so a couple old towels draped over the tank are your best friend.
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I use a floor jack under the front tire to find the sweet spot on loosening the steering head but. I should state the bike is on my hoist... Front tire on floor jack...
Sometimes the magic trick is getting the handlebars riser bolts out. ...
The X I put Jamie's update on, the OEM bearing was seated in orange loc Tite. It was a real bear to remove. Sparks and pieces flying all over the shop.
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Adding to what the others have already shared and some more:
The wobble can be a number of things and they're common to all motorcycles: tire condition, tire pressure, steering head bearing wear and preload and even suspension settings.
I was recently on the phone with Marty and she said that they had one that was the result of a worn shock. A new shock fixed it right up. There's another data point for you.
Back to the steering head bearings because they're obviously where you'd start (right after tire condition and pressure). As it sounds like you're aware, the bearings on most big bikes need a little bit of preload to create some drag in the steering. My old Honda GL1200 Gold Wing specified that with the tire in the air, the bearings needed enough preload that with a fishing scale on the end of the handlebar, it took 14-18 oz (roughly a pound) of force to get the bars to start moving. If you think about that, it's quite a bit. Under that amount and the Gold Wing would have the same death wobble.
To get at them, you'll need to obviously get the bike up on some kind of center stand or lift. Unlike a normal bike, the second you remove the fork crown, the front end is going to collapse unless you have the weight safely supported.
Please for the love of all that is holy, remove the tank before doing this job. There's too much stuff clanging around that can damage it. Remove it now.
- Remove the four handlebar pinch screws, lift the bars off and try to set them somewhere they won't dent the headlight bucket or front fender (towels and tape to hold them everywhere).
- Under there are two 1/4-20 screws with tiny hex sockets. 50/50 chance of stripping the head and needing to drill these off.
- Slide the handlebar risers off to reveal the riser studs. Remove them.
- Remove the brake hose clamp screw on the front of the fork crown. This becomes important after the next step.
- Remove the chrome acorn nut. I have personally found that a large adjustable wrench and a paper towel over the nut are far kinder here than attempting to use a socket.
At that point, the top crown should be free enough to hinge away from the upper nut and bearings. Or--if you prefer--you can remove the 1/4-20 socket head cap screws on the top of the struts and remove the whole thing.
From there, it's an obvious double-nut arrangement. The thing I'd share there is: it's hard to tighten the bearing and have a wrench thin enough to hold it while trying to also snug up the jam-nut.
To make this step easier, the answer is a hydraulic wrench. They are thinner than standard open-end spanners. Sorry, I don't remember the dimension of the nut. The wrench I bought on ebay is a Proto and it's a double-ended, 1-3/16, 1-1/4". From the marks on the wrench, I'm inclined to say it's the 1-1/4" side that fit but, I can't swear to that.
After fighting with the adjustment once and still not getting it right, I made sure I had the wrench for the next go-around. Picture from ebay attached. There happens to be one loose wrench for $19.99 that I got that pic from.
Assembly is reverse of removal.
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Bearings phase two:
If you are a glutton for punishment and actually want to replace the upper bearing, here's what you need to know.
The upper bearing is a conventional, sealed ball bearing like you'd find on the wheels. In fact, it's exactly that: the same bearing as used on our wheels, a 6205 metric bearing. That's a 52mm OD, 25mm ID and 15mm thick.
The closest tapered roller bearing is a 30205 or 30205M: same ID and OD but, 16.5mm assembled height. See attached image of both bearings.
The question is: what do you do with that extra 1.5mm of height? Atlantic's answer is they send one of the crown nuts to a machine shop and have it shaved down by the difference. In my case, I made shims to go on top of the rigid fork, around the riser studs, below the crown. Either works.
My shims were just over-glorified washers. I do have to say though that rather than go by calculations, I actually installed the steering crown after assembly and measured the gap to get it exactly right. In my case, I snugged up the acorn nut and the gap was closer to 2mm or 0.080". That's the thickness of washers I made to go in there. Yours might be different.
I must add that taking the entire rigid fork off opens a whole 'nuther can of worms. You'll have to remove the front wheel, disconnect the brake plumbing, remove the fender, disconnect the lower rockers, etc, etc. In theory it's possible to get that stuff out of the frame as an assembly but, the weight, the clumsiness and everything else will conspire to damage your fender. Just don't. It's a good time to take everything off and clean it anyway.
You may not head down this path but, I posted it just in case or, for someone in the future.
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Interesting note Greg....
I didn't know anything about the difference in width on that bearing, when I installed it. Or that anything needed to be shimmed...
Not sure where communications failed on that one...
Well as far as I Know, Chad Ardnth's Jennie is still handling fine after I installed that bearing...
thank you for bringing that to my attention...
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Bruce,
Yeah, I was afraid that top crown would not take up that extra gap without rocking weirdly to one side and only supporting one side of the top bearing. I measured it after assembly to see if it would cinch up or not. I wasn't comfortable with what I saw so I made the washers.
Since not everybody can make an aluminum spacer, here's a better option for most people. Keep in mind that hardware store washers can vary greatly in thickness, even within the same box or bag. That's why I'm not recommending just any old bag of washers to use as spacers.
Mil Spec washers: NAS 1149-F0863P are for 1/2" screws and are specified to be between 0.059"-0.067" (right at 1.5mm). That's tight enough tolerance for what we're talking about here.
McMaster Carr sells them under part number 95229A550 and they are currently $11.97 for a bag of 100.
https://www.mcmaster.com/95229a550
One on each side, under the fork crown will take up that gap. No, they aren't the perfect solution. The right thing would be a nice oval shim, the shape of the top of the rigid fork. Nonetheless, nobody will ever see them tucked up under there unless it's up on a lift or they're on their knees waxing and polishing.
The other direction is people could buy a spare lower locknut from ehparts.net for $9 and have it thinned by 0.060" before disassembly. Then there would be no waiting for custom machining. Install it and go.
I have this mental thing about permanently altering the factory parts, even when I know they will never, ever go back to stock. I also didn't want to machine through the zinc plating on the nut and create a place for rust to form. Stupid, I know.
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I've always thought the factory just made a strange and possibly cheap choice for the upper bearing as a radial ball bearing such as the 6205 isn't rated for much thrust load and while theoretically the upper bearing in the neck takes little thrust we all know most bikes need a bit of drag or friction here accomplished by tightening the bearing set up axially. The 6205 most likely quickly loses any preload and develops slop or play.
A drop in alternative to the 6205 which is designed for combined radial & thrust loads is the 7205 angular contact ball bearing. You have to install it with the correct face up on the inner ring so as to have the line of contact facing correct. Designers would reference this as "load center up". The races should be marked as to which is the thrust face. Most 7205 bearings are a 40 degree contact angle but I did see one which was 15. A 7205 2RS would be a sealed variety. They are more expensive but would require no machining or shimming and considering a lot of the 6205's run quite a while if you keep the play taken up a 7205 would likely last a very long time. If you ask me the factory was pinching pennies here.
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That's actually a very good option I hadn't considered. As you stated, it's lower axial load carrying but, the 6205 bearings have been doing an okay job for many years so your solution is probably very workable.
I will say though: can you imagine the recall nightmare they'd have had on their hands if the person on the assembly line wasn't paying attention with the installation direction of those bearings?
The other small issue that remains with the tapered roller is the gap between the dust shield and the steering neck. It's obviously 1.5mm further away and now more slightly more exposed to the elements. I compensated by filling the pocket with grease but, that'll only last so long.
The perfect solution would be a new top nut and dust shield to go with the tapered bearing. Hmm...
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As I get older I find I know less and less....
Please correct me if I'm wrong on this...
You 2 know your way around "bearing world tech".... I definitely do not...
Rich..... correct me if I'm wrong....
But you are saying the 7205 2RS would be a good replacement of the OEM 6205?
That it wouldn't need to be shimmed as Greg is stating?
If this is all correct.... that's an easy answer.... 7205 2RS it is
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There's no right or wrong answer.
The 7205 bearing will apparently work without shims or other modifications. It's also much more expensive than the regular tapered roller. McMaster lists the 7205 2RS for $195. The 6205 2RS is $10.89.
Bearings are available cheaper elsewhere but, that'll give you some scale. The 7205 has lower thrust rating than the tapered roller but, it's better than the 6205 that was doing the job all these years in almost 2000 motorcycles.
The tapered roller will go in with the addition of two flat washers (as shims) and it's cheaper. Downside: it's not sealed and will leave a slightly larger gap where the dust cap sits.
Use whichever one makes you comfortable. Cost-aside, the "7205 2RS" (2 rubber seals) is a hands-down winner against the original 6205 bearing.
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I use mccmaster/Carr a lot. I like the quality..
After I did the post yesterday, I did a quick Google for the bearing, with nothing near that expensive. Mostly 50$ or less, some austria made... It didn't show mccmaster..
Not purchasing yet, but that's quite the price difference.
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I saw some of the same prices you did but since those may be surplus or counterfeit, I wanted to make sure we were comparing apples to apples. I’ve had some bad experiences lately with Chinese counterfeit parts from the internet. Bearings are notorious for that.
The tapered bearing I bought for the Deadwood did come from eBay but it was in an old, shelf-worn Timken box and the bearing wrapper showed similar age or I wouldn’t have trusted it. That was $17. There were similar parts down to $5 but I wanted genuine stuff.
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Oh boy I'm up to bat.....
Gonna do the triple tree bearing... got 2 on order,... one for 525 and Blue... will be doing next week it looks like...
WITH that thought..... I was running thru the information here on this site.... and can't seem to locate the OFFICIAL torque numbers on that nut....
If I remember correctly its around 90 pounds? .... If you know the number, give me a shout here... and if you found on this site, let me know where its hid... thanx...
Been working on 3 different Xs so far since retirement. Mine, blu (my nephews), and Darins... Waiting for brake pads on Darins, and it will be ready to head back to Omaha.
Was changning oil this morning in mine (525)..... and dad gummit.... pulled the threads out of the back oil plug..... GEEEZZZ ....
Went into a short panic, then calmed down as I've done one before on Jeff Browns Tribute X.... way back in the day.... that dawned on me that Jeff had bought that Time Cert kit just for that oil plug. Gave him a call.... yahoo, and he has some inserts too... So this weekend I'll be rounding up all sorts of padding to lay 525 on the cement.... wish me luck... it won't be bad actually pretty simple...
Bruce
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Bruce,
You may have different tools than me so take this with a grain of salt. I don't have a deep, 6 point socket large enough to get on that acorn properly. I have a 12 point that marks up the chrome and I have a 6 point standard impact that is too shallow to adequately engage. After damaging the nut on one of my bikes, I went back to the simple solution.
I now use a giant crescent wrench with a paper towel folded between the jaws and the chrome. I use it to achieve the German torque specification of Guudentite. It's less than a 90 lb pull because I'm a weakling and I'm more worried about the chrome. Close enough for me.
Someone else should be along shortly with the real number that you can use with your velvet-lined and totally equipped tool chest.
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Normally on the chrome fasteners I use a wrap of electrical tape to protect the shiney bits...
As for the acorn nut the book says I believe 50 pounds. The torque I'm looking for is for the nut under the triple tree plate that compresses the bearing.
I could be full of hooey..
Thanx
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Ahhh, that one. I’ll be curious to read how other people do that. I’ve adopted the method from the Honda service manual for my old GL1200. On that bike they called for measuring the bearing preload with a fish scale at the tip of the bars: 14-16 oz of pull to get the bars to start moving (with the wheel in the air). Basically: “just a little drag but not too much.”
With the adjuster nut, the jam nut and the acorn contributing to the final preload, it takes a few tries before I’m happy. I snug the adjuster, then jam the thin nut down with the hydraulic wrenches. I want part of the final drag to be present but, not all of it. Torque values aren’t important because this stuff is all stacked up with the top acorn. Then I reinstall the crown and tighten the acorn before checking the result. Usually it’s too loose and I have to take the crown off and give the adjuster another smidge.
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Thanx buddy!!
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Ok... then.... I'm not real OCD, but certain things just get under my skin..... lolololol
I could not for the life of me find the torque values on that flange nut (part number 1300-0033) under the triple tree plate. I'm sure someone way more smarter than I can find it. If anyone does finds that torque value, please let me know where you found it...... so I called Jamie/Marty...
The torque for that piece, Jamie is using is 25-30 foot pounds. And if you still have the lock nut (part number 5199-0500), and ignored Bobby Xman Baldwin from back in the day, it will be 25 foot pounds on top of that.
Jamie also said as a reminder, before you do any assembly, and torquing to make sure you repack that lower bearing.
The Acorn nut on top of everything is still the same .... at 50 pounds. Jamie made a point to say that, the acorn nut doesn't actually hold the triple tree plate, but the support fork bolts do...
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Wait, what’s this bit about Bobby not putting the thin jam nut back in place? I hadn’t heard that before.
How did the time-sert installation go?
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I believe Bobby's direct quote from his instructions on the triple tree death wobble were to take it and Chuck it to the neighbors yard.
The time sert event to replace the rear oil plug threads went quickly and easily...
My boys helped lay 525 down on blankets towels and cardboard. And then scratched their heads as they watched the old geezer perform...
Went very well, no issues
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I wonder if Bobby throwing out the top nut was part of installing the tapered roller bearing on the top. That nut is probably close to the thickness you would need to remove to match the additional height of that bearing. I considered tossing it when I did mine but opted to make spacers for the sides instead.
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There was no bearing update at that time as in tapered bearing.
This update was for reloading a new torque, to prevent death wobble.
Well that's how I remember it....lolol
Pre superXparts for me.
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As follow up on the bearing replacement for the upper bearing I found it interesting that a late 40's Indian I am restoring uses a 7205 angular contact ball bearing up top and a 7206 in the bottom both of course metric race dimensions. So I thought it was interesting that some 70+ years ago designers were applying these style bearings for this application. These were not sealed back then but had external grease fittings which kept these in great shape.
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Interesting indeed. That seems like an expensive choice for that time, considering where manufacturing technology was.
Are you restoring a Chief or an Enfield? You know much about them? I've tried to search around the web a few times but, never found an Indian Arrow quite like this one. I wanted to know if this was aftermarket parts or they made a high-pipe variant. It's hard to find anyone who even says Indian Arrow without spitting afterwards.
My dad, Galveston, Texas, some time around 1955:
(http://www.cifumotorsports.com/ak/DadsIndianArrow.jpg)
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oh my thats cool....
Interesting indeed Rich
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It's a model 348 or "Chief" I was wanting an old flathead, preferring a HD U/UL/ULH like my father had in the early 40's but they are harder to find. This one came across and I picked it up