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Discussion in 'Airheads' started by bbcmat, Sep 11, 2011.
What does that mean? Did you get one of the ones that the urethane didnt cure correctly?
If I remember right, the ones that had the urethane disintegrate also had leaky output shaft seals and had gear oil on them? Did anyone ever look into whether the gear oil may have degraded the urethane or was this just an issue of inadequate mixing/portioning of the two urethane components?
I had heard it was simply a few shafts that got mixed wrong. If it was gear oil, mine would have blown
It does not. The hole is through the center of the pin, not through the bearing.
With solid pivot pins, the only holes are bottomed and for allen wrenches, the factory data says " vents through pivots" ???? Swingarm pins solid, FD pins solid, and screwed down rubber boots fore and aft . Along with factory warnings to "not grease bearings" ? That is why I assumed there's air where grease is sposta be comment . That along with the sorry. lame a$$ so called seal that come with the SW bearing . It;s a hard plastic spacer, and little more . IMO Beyond abnormal air venting, ie. " thru a bearing", there was no venting in this swingarm . That prompted me to drill the SW and put the undersized cotter pin in same hole .
There is a small triangular hole above the outputshaft seal that works as a breather hole for the swing arm.
Those holes can also cause gearbox oil to leak into the swing arm. The oil vapors causing the grease of the u-joint bearings to get thinner. Therefore not lubricating the U-joints like they should.
This same problem happens with drive shaft splines of the K75/100. But than its the leaking seal in the FD most of the time.(or gearbox)
The re-buildable shafts should be serviced every 10,000 km !! As was told to me by Mat from the Boxer Toko.
IMO Trying to get grease trough the grease point is tricky. As the grease is pushed trough it "should" lube all 4 bearings.
But I have often seen that the grease takes the easiest way out and will squirt out of 1 bearing. And its not going trough the other ones.
When those axles where new nobody could tell me what type of grease to use.
After asking a company how did nothing but re-building drive shafts, they gave me some grease that is so thick and sticky,
that it will never be possible to get it trough the holes into the bearings!!!
So every time I took it apart and stuffed the u-joint bearings and mounted everything again.
(i'm sorry I don't know what type of grease it was)
10,000K's, even 10,000 miles is too short of an interval to go taking that poor thing apart
I just had a driveshaft rebuilt by Bruno in Canada.Not a GS this time, but still a BMW with the very same U-joints.And that one spins much faster.... I think his recommendation is lube at each tire change. It now has over 10,000 kms and is on my bench. I may just remove one of them U-joints and see for myself how much grease is left. I bet there is plenty and then I'll make up my own mind as to the lube intervals.
His recommendations for lube is Synthetic grease, so I just went to the marine shop and bought Amsoil synthetic water resistant.
If I have a chance I'll dig up my pics, may interest some as to what I found for cause of failure on some of them U-joints. Looks like moisture may just seep in between the yoke and U-joint caps, create corrosion which in turn tightens up the caps over the needles/cross....creates more friction/heat, grease runs out and then the joint fails. I sure found corrosion between the caps/yoke and wear marks inside the caps that almost exactly match with the outside corrosion.
So now....to prevent that ingress of moisture, I coat the outside with very sticky grease, as in cable grease out of the 5 gallons buckets at work.I don't think there is anything stickier on the market. Sure was still all there when I removed my driveshaft after 10,000 Kms.
Or.....I could also show my parts to Mr. Jackd, may have some time and will be on the big island toward the end of January. Clean enough to put on the table at Starpucks, they are BMW after all.....
Hell jackd, come down to Memphis and I'll let you replace my GS's swingarm and FD bearings.
I'll even let you setup a tent in the yard for free!
^^^ Bring me some aerospace grease, I'd be all over that.Yes need a better analysis of them U-joints. I know that not many, if any have taken one of them out to check for possible causes of failure. Shail sure does have interesting toughts on them, also has to do with angle of operation. From what I know now, 16 Degree should be MAX, watch the preload.That's according to a Kiwi/Dutch that...!
I should put in a good word in for Bruno, I did have a quick turnaround on the K. Couple weeks and no welding on the shaft to accomodate the circlips grooves. That reminds me I should check the specs vs OEM, he may be using a slightly shorter U-joint to do that. Need to do more comparisons, a few driveshafts here to do just that.
Not that easy pulling one of them U-joints out without destroying the evidence.:huh
Pivot bearings....now $67.00 each!:eek1 Good thing I like to maintain mine, and take them apart with the dental pic. Still using the old BMW Red Jelly on them, got to finish that tube.... almost done after 20 Yrs or so. May switch to Amsoil Synthetic, now have lots of that.
Red Jelly....the old controversial BMW spline lube.N/A now and hasn't been for a long time. Looks just like the old Texaco No.5. Quite familiar with that one,Texaco...my youth. Also long gone...! And "Red Jelly" because it also looks like some of them cake decorating jellies....!
It is just that, extreme pressure red bearing grease.
I'll do some measurements on them U-joints and pics for sure. I just installed my repaired K driveshaft and rode this summer, my rule is "NO wrenching in the summer". Maybe I'll take one U-joint out, would remind me of my youth learning that with grandpa. Not that I did not practice U-joints replacements later on.:eek1 Mexico...old van...a jack...hammer...sockets. Back on the road with a new "cruceta". Even the parts guy did not know the proper spanish words.
Give me a few days...shop is a mess and .
I'll find you some needles....
Thanks to all who've helped on this string . I bought this mc 10 years ago with virtually no miles on it . 65,000 miles, and 3 years ago I started riding it . After weighing the $400-600 investment and the "prudent" 10,000 mile greasing and general servicing of the paragoric driveline/driveshaft on my 93gs . I have decided, It's being retro fitted with a lengthened SA and DS from a vintage mono RT . My other ride is, an RT that has 160K miles on it . I never even looked at the driveshaft, every 20K I'd lube the trans spline . At 50K remove the trans/SA/DS to clean the clutch & it's cavity . To date all the failures in my gs driveline have happened within 200 miles of home base . What I consider very good karma, at about annual, 20,000 mile intervls . I do not want to rely on karma to get me outa Mexico anytime . Front SA brgs, rear FD brgs, and now the DS have failed . The original DS lasted 65,000, ammazzing miles . Looking at 10 to 20,000 miles of riding between the misery of maintaining that driveline is not enough IMO . For $342. delivered, a complete pivot pins to wheel bolts, drive line from a mono RT has arrived here . $342, along with the machine cost I can't handle and the professional wheel build, lie ahead . One such guy outlined the project on ADVR, many thanks, he spent $1500 . This plan has become my way of dealing with paragoricdriveshaft short falls, if it happens inside $1500, I'll be thrilled . My caper south of the border this year is off . One orig DS in vg condition one needing rebuilt, 2 FD's and 2 SAs', the Ohlins 541 . Are about to hit the market, as a result of this desision . I wake at night since this escapade began, with thoughts of this para DS crapping out in the frontier between San Cristobal and Chetumal, on a 110 degree day . Or on the mile high dirt roads of Oaxaca, down into Tapachula . At those temps, and in those locals, where are you to find a "heatgun" or "torch", Just to get it apart ? If in fact you locktite the steel pin to the alum housing ? That's why a year back I began using permatex and marking the pin, with daily inspections . Yesterdays AirMail arrived with another guy asking Oak what to do with the stripped out threads in his gs SA . Along with another gs guy who's rear u-joint failed . I am moving forward by heading rearward at this point . It's been a 3 year crash course in the gs mode . The mc was coined Karma, when the SA bearings went away in Cumberland, Md. after 20k in Mexico . The name was changed to "KarmaNewt" after the FD bearings went away in Richmond, enroute home from Mexico the next year . Karma, because she always gets me home . Newt becuase working on/with it is like dealing with Newt Gingrich the ex unyeilding speaker of the house . Thanks again
Increase the maintainance is the only option . My first gig when I bought the gs was the transmission c-clip . Then 4 piston caliper on front, LED lights, Ohlins and PD tank . I figured all along the 20K servicing mode would be cool, so I began the Mexi winters . 20K maintainance worked on several RS and RT's down thru the years . However in 3 years and 65K, things went away on the gs at around 20K intervals . Then reading in this thread, I come away thinking @ 10,000 miles, grease, the DS . There's entirely too much work involved to hypothetically say make it10K in Cancun, where I have a friend and could work on it .Or where ever you might be, find a safe place to disable the machine . Have enough parts/tools to go back together . I did carry all the brgs and tools for the SA/FD, along with elec. stuff a bean can, parts to repair the crashbar oil cooler, etc . I had a spare Trans,SA,DS and FD in Pa, that DS is now in the mc . DHL is about the only safe way to get parts into Mexico, 3 weeks and big bucks . Unless your in Cancan and can find a sport fishing guy heading there . It was I thought pretty much figuered out . I agree the DS lasting 65K was ammazing . I am not at all anal about my rides, I do perform maintainance at pre determined intervals . Using this one the way I do, unless I start a 10K program . I believe it's only a matter of time til it happens some where I don't wanna be . We will see and thanks for your input .
While looking at the FD and SA . The FD bearing is minimal to say the least . The rollers are grossly under sized to handle the loads, without indexing/notching . I doubt the pivot pin diameter could be reduced by 50% . The only option is a larger in every way bearing . That IMO requires build up alumnimum weld in the FD bearing recess areas . Likely inside as well as outside . Then remachining the bearing cavity to accept a larger bearing . Can that happen without modifying the inside of the SA at that point ? Quien Sabe, Who knows ? I in fact think the Rubberchicken bushings are a great carry along n fix item, and about the same price as the mini bearing . I have a pair in the tool kit now, they've been there 3 years . The originals can be beaten out with a muffler chisel , then beat the rubberchicken back in with a socket . I believe a bit more sucessfully than the fragile factory mini bearing that you're trying to keep clean roadside . In 265k on airheads, I never had a swing arm bearing fail, til the gs . I always pumped a shot of grease in the pivot hole @ 20K spline lube . They're in a bottomed hole, put grease in, the pin forces it into the roller area . The gs they say don't even try to lube them . I never had a drivshaft fail, til the gs, never had a final drive bearing fail, til the gs . That along with the less problematic later model gs . Tells me the 93gs era has a design shortfall . That you either accept or retro fit to re atain airhead ridability . The icing on the cake is the mention herein about the 10,000 mile grease the DS routine . This is the first time I ever heard that timeline, alas, it is not going into my program . That sounds like hauling your boat every month to see if the hull is sound . I think I'm heading back in time to a machine I can maintain at 20K intervals . While carrying the known airhead potential problem parts and eliminating others . Starter, lame charging system, shock, and adding efficient lighting . The proof for me was in the $$$$ department . Beyond this, my retirement time is worth more and more cash, every year . The years are running out, loot can be found .
Final drive gs, big $$$$ one ratio . $100 in bearings that will fail . I have 2 to get off .
Final drive mono, a song available in various ratios . 4 bolt replacement no bearings .
Driveshaft gs rebuild or replace $475-$600. Rubber in the middle ??? Treasure it's existance . Deal with too often . Have 2 to get off .
Driveshaft Mono, a song, maybe $200 quoted max, to lengthen, mine has 50K on it . I'm runnin it, no rebuild now . If it craps out then yes . Refer back to the "never had one fail" statement . No rubber in the middle, instead a heavy spring buffer on the end .
Swing arm gs $100 in bearings that will go away . Have 2 to get off .
Swing arm Mono . $50.00 to extend, a retired pipe fitter buddys' on it now . I'm running it with the nice smooth greased bearings that are in it .
The wheel is going to cost some big $$$ I need a rear gs hub, have a couple rims, no hub . Only one stock gs wheel .
Time will tell, the motorcycle is a blast to ride and has done everything I ever tried with it . Good mileage, great on tyres, and so on . However , my patience is taxed every time I deal with it's driveline . Maybe I aged a lot more in the last 3 years than the 55 before that . Or maybe I'm just stuborn, old and hard headed .
How often do you think the U-joiunts need grease?
I know they say 10K, but I feel thats just too short an interval.
I'll think that any grease is better than no grease. But I'll listen to Bruno on that one, for once I got to buy a synthetic lubricant I think that's a first for me.
Got real busy before Christmas and had to come to work Christmas day, but do have pics of the Amsoil, it is marine rated but also compatible with any lithium based lube. Good enough for a boat....good enough for me.Cheap anyway all things considered, $14.00 for three cartridges at Trotac Marine in Victoria, will last me well into my retirement.
Also waiting on some Guard Dog Moly for other purposes, someone dug the info out and apparently recommended for U-joints. Don't know would have to check the specs for myself before, I know it is a Lithium base.
Still debating the maintenance schedule, will have to remove one of them U-joints just to see what's left in there. Probably all that was put in 12,000 Kms or so ago. Too busy with failing equipment at work to think bikes much. I am calling on the senior engineer too often and feel guilty, after the next steak dinner I guess I could snoop around with him and see what he thinks on greases.
Then I'll have to show you some of my U-joint pics. Another couple weeks and I should be free.
Can't ask too many questions, we are pretty busy, to the point that I have to fix some of my own stuff.:eek1 Will be calibrating thermostats all day amongst other things. I owe him already on the nice machining job he did for me, new cone for my wheel balancer but he balked at using brass.
Schnitzel dinner coming up.....nothing is really free.....!
Jackd, how many miles do you have on this new driveshaft??? I have purchased the same driveshaft but have not installed it yet???