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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: cgdan on September 01, 2016, 11:27:14 AM
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Right, while looking at the K100 and assessing what to do regarding removing the gearbox etc for spline greasing, I have noticed a little oil around the drain hole at the back of the gearbox housing. So I am guessing a seal has gone somewhere.
As this bike has been standing so long and I would guess all manner of seals have dried out, I was thinking of replacing vulnerable seals when I am in there. Anyone got any recommendations for which ones to pay attention to? I was thinking engine rear main and trans input shaft, and the clutch nut o-ring. Anything else I have missed? Are these hard to do?
Many thanks
Dan
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Are these hard to do?
Yes and no. :giggles
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So I am assuming that means yes and yes :mbird
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So I am assuming that means yes and yes :mbird
No.
It'll be "hard" if your thumbs are zip-tied together and the only tools you can use are a pair of chopsticks and an enema bottle; otherwise, the full procedure in the manual gets read, descriptions of the process are read here, videos are watched, tools and parts are assembled, a space is cleared then work is initiated and completed.
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Fair enough, but I threw the enema bottle out last week.....
Seriously though, I was just wondering how far to go, what seals would you change or not as a precautionary measure? I just remember going a bit nuts on my old Honda Silverwing (CX500 thing not scooter) and some of the knuckle skinning and swearing really could have been avoided by speaking to some people who had a bit of experience on what will wear out and what really doesn't need touching.
Cheers
Dan
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... work is initiated and completed.
Then if you're me, there's just one more little step: repeat until fixed.
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Then if you're me, there's just one more little step: repeat until fixed.
:hehehe :laughing-on-ground: Yep. I forgot to add that step.
If anybody thinks that this subject hasn't been discussed ad nauseum here and all the way outward to the far outposts of the K-Bike universe already, and that the only way for anybody to obtain that information is for it to be hand-delivered to them by creatures from Mordor or Flint, Michigan, then surely they've been raised by unicorns and sequestered in the Magic Forest until they were released to buy their first motorcycle.
That reminds me; I've got to polish my emesis basin.
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Steady on Laitch, I only asked for an opinion as it seems to quite divided across the K-bike universe........
I'll have a tear down over the weekend and have a gander.
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Mine had a drip there too. Bike had not been riden much.
I rode it 200mi each weekend for a month.
Leak stopped.
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Hold on, there, cgdan asked a reasonable question that nobody addressed, and Laitch has him for lunch for not doing research ! That's not the K-Bike way! Surely someone here knows if some seals are more prone to fail? Nothing wrong with asking experienced owners.
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Do you know which seal it is that is potentially leaking? There is one for the output shaft that spins the driveshaft. Oddly enough, the clutch boot is very prone to leaking too if not properly adjusted. They also crack and make quite a mess of things as a result of age and poor adjustment. There is also a gear selector switch/meter thing, but I can't imagine it would be that.
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Its leaking (very very slightly) around the little hole under the clutch housing. So my suspect is the clutch o ring due to lack of use. My fear is that if I do that and nothing else something else will go pop very soon after. Then again, by attempting to change something that may not need to you unnecessarily increase the risk of damaging something else. Oooh the home maintenance conundrum! What would you guys do? Change every seal you can get to? Leave certain ones as they are an arse and never give problems or just leave the whole thing, monitor how good downshifts are and see if any leaks get worse while riding the bike as much as possible?
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I had a weeping rear seal behind the clutch. You need to mark all the clutch components so you can reassemble in the same orientation, the components are balanced in relation to each other. While you are there measure the thickness of the clutch friction disc 4.5 mm thickness minimum. Replace the "O" ring you might need a clutch alignment tool which can be bought or made or if you are really good you can align it by eye. Clean and grease the splines, check the rubber boot on the clutch rod for tears, check the gearbox input seal. this is also a good time to fit a grease nipple to the clutch pivot arm.
Regards Martin
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Did you end up downloading both the factory manual and the Haynes manual, which are online? Cliymers makes a really good one too that you can pick up online as well. I would highly highly, and I will say it one more time, HIGHLY recommend you use at least two of the thee publications. That factory manual will tell you how to do it the right way and the other ones will give you tips on how a smaller garage or private mechanic may be able to do much of the work. Read through those first and decide exactly which parts, tools and equipment you will need to do the job, and to do that job right. Even in the 80s when BMW first started making the K bike, they used very tight tolerances, and by tight, I mean... The fasteners and the threaded bodies for which those fasteners go into are either steel and/or aluminum in almost all cases. Obviously, you do not have to do this, but you would be wise to pick up a torque screwdriver, a 1/4 inch torque wrench, a three eights inch torque wrench and a half inch torque wrench to do the job. I use the torque screwdriver for things that use the smallest tolerances but are very important, like the hall-effect timing wheel and the sensor.
The particular focus of this thread focuses on the area in front of the transmission, and not the back. In particular, that weep hole should be on the intermediate flange if I am reading your most recent post correctly. My money is on what you have suspected. No guarantees of course. As long as you are making the effort to get in and do the spline work, you should absolutely disassemble your clutch pack and replace that seal. I am the kind of guy that will use new hardware as it is recommended by BMW, but that is just me and, admittedly, not 100% necessary. I would absolutely replace those little star washers that keep the pack itself together though. Some people use Loctite; to each their own. There is more than enough reference material on the web to do the job and get it done, but don't kid yourself into thinking you will find everything in the order needs to be documented. Get those manuals and find the torque specifications and where to apply lube and what types of sealants to use where. Things like acetone on your non-painted sealing surfaces with Hondabond work magnificently.
All of this, being my opinion of course. Let me know if you don't have those manuals, and I will either personal message those to you or find them and post them up on this thread.
It seems that the last few decades has seen a few conversions change. Of recent, the latest newton meter to foot pounds seems to be 0.738 FYI.
Another amazing source is realoem.com. Enter the last seven of your VIN and you'll either see the parts breakdown for your bike, or the updated parts for your bike; all broken down by sub-system. All of it includes individual part numbers and approximate costs as well. I printed every single page for my rebuild because it also told me, in most cases, the order the parts are assembled and which ones were supposed to be there and which ones were not.
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Its leaking (very very slightly) around the little hole under the clutch housing. So my suspect is the clutch o ring due to lack of use. My fear is that if I do that and nothing else something else will go pop very soon after. Then again, by attempting to change something that may not need to you unnecessarily increase the risk of damaging something else. Oooh the home maintenance conundrum! What would you guys do? Change every seal you can get to? Leave certain ones as they are an arse and never give problems or just leave the whole thing, monitor how good downshifts are and see if any leaks get worse while riding the bike as much as possible?
See my post a few up. Ride it.
But if you are going to take something apart as old as these things are, replace every piece of rubber you find on the way in and out.
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Thanks ever so much for all the replies.
The overriding theme seems to be summed up nicely by mlytle. As I am going in for those splines its new clutch o ring and main rear seal for me. Inspect everything else carefully too while I am there.
So I have...
......a BMW workshop manual.
Clymer and Haynes coming in next few days.
Bought new clutch o-ring, washers and bolts. (Motorworks)
Castrol optimoly (Motorworks).
Currently wearing out printer with all those diagrams.
New bigger torque wrench being purchased this afternoon ( I only currently have 3/8 and 1/4 ones). Probably going to get some nice torque screwdrivers too. Always wanted a set.
Some carpet snagged off a building sight.
80 tea bags and a new pot.
The wife is steadily regretting getting me this bike :eek:
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There are some very specific lubrication points when reassembling the clutch, FYI. Make sure your comfortable using just a smidgen of grease where applicable. As for lubing the spline? Ha! Ask 100 of us, and you will get 100 different responses. Oh, while I'm thinking about it, place a very light coat on the alignment dowel when you replace the gearbox; It'll make life easier for the next guy, which will be you of course. :2thumbup:
The one thing missing from your list is a clutch alignment tool. You can get lucky/be patient and forgo one, but they are great to have.
Where in the UK are you? Close to LHR perhaps? I'd have no problem lending you mine; I'm there at least every month or two.
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Forgot to mention Ive got one of those coming soon too! Very kind to offer though :). I
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Dry as.....