Author Topic: 1987 K100LT went "klunk" and no power to the rear wheel (Read 17175 times)

Skids · « **on:** January 09, 2016, 10:39:53 PM »

I was riding close to home this afternoon on my 1987 K100LT and all was going smoothly till I made a gear shift and I heard a "klunk" sound and had no more power to the rear wheel. Engine still running, but there was/is a slight get noise, a bit like grinding but not that bad. It starts and runs OK, and when I shift I still see the gear indicator changing, but nothing to the rear wheel. I know I'm going to have to take off the wheel, rear drive, etc., but I'm not sure what the problem is. Could it be the clutch, drive shaft?

If you have any insights I'd be glad to know.

Thanks,

Skids

Chaos · « **Reply #1 on:** January 09, 2016, 10:57:10 PM »

Pull the rear end off, likely the splines on the drive shaft are toast. There's are a couple places that can fix them or you can try to find a used set.

Skids · « **Reply #2 on:** January 10, 2016, 10:57:25 AM »

I think you are probably correct. I'll pick it up later today and look forward to the opportunity to learn how to repair this item.

Thanks for the reply.

Chaos · « **Reply #3 on:** January 10, 2016, 11:10:33 AM »

I have not used him but this shop has a good reputation on this and other forums for spline repair; http://www.brunos.us/

Skids · « **Reply #4 on:** January 10, 2016, 12:07:13 PM »

Thanks for the info. I'll take my drive apart and will likely need to send it off to Bruno.

Skids

Elipten · « **Reply #5 on:** January 10, 2016, 01:20:46 PM »

Bruno is a busy man typically and difficult to contact. Very slow at answering email in my experience. Best to call and leave a message and number for him to call you at. Can be a long wait for repair he has a a backlog when I had mine done.

Work is first rate. Also have him machine u-joint for circle clips and grease or replace the u-joint while in there. I would put the cup in the driveshaft splines so the grease does not walk up the inside of the shaft. Shit German design what else can be said.

My 2 cents

F14CRAZY · « **Reply #6 on:** January 10, 2016, 02:06:58 PM »

It's also possible that the splines in the clutch disc hub are toast. When I lubed mine I found the splines were close to questionable to i replaced the disc a few thousand miles later. Trans input shaft splines were fine though

TimTyler · « **Reply #7 on:** January 10, 2016, 02:10:14 PM »

Skids,

Looking back at your earlier posts....

Quote

"It must have been dropped at least once, since there are some cracks in the fairing, fairing pieces missing, the right glove box is cracked beyond repair, the antenna is missing (it has an old radio and cassette player in the left glove box), the front wheel is black while the rear is silver, assorted screws and fasteners are missing, there are some cracks in one of the saddlebags and top case. The fuels guage was taken off but I have it as the previous owner said it didn't work."

Since this is a new bike for you at 62k miles, and it was relatively cheap, I recommend you think hard about how much $$ you want to invest in fixing the bike. If the splines are bad, the idle is fluctuating wildly due to air leaks, and parts and hardware are missing you might be better off cutting your losses and either parting the bike out or keeping it as a parts bike. It's pretty easy to spend a lot of money replacing old rubber bits, worn cables, leaky seals and rusty bearings.

Skids · « **Reply #8 on:** January 10, 2016, 06:10:39 PM »

Tim and all, thanks for the comments.

I got the rear drive off and the splines are bad on both the drive and the shaft. If I am going to fix this, through Bruno's work or otherwise, what else should I check out/fix while I have it apart. I imagine I will need to take off the swing arm to get the shaft free. Are things like clutch replacement a good idea at this point? Anyone know about Bruno's prices offhand?

Tim made a good point about whether or not to fix this. I did get it running quite well after fixing the air leaks, changing the plugs and some fluids. It was running very nicely till this event. I paid $1,200 for this and have put another 200 into her so far. I had purchased this recently to find out if I wanted to get back to riding after being off for many years. The answer is yes and I even purchased a 2009 K1300s which is a blast to ride.

Again I thank you for your comments and any further comments that might help me decide what to do, go ahead and fix this or not, and if I do what else should I consider fixing on the bike at this stage.

Thanks,

Skids

F14CRAZY · « **Reply #9 on:** January 10, 2016, 07:42:00 PM »

Quote from: Skids on January 10, 2016, 06:10:39 PM

Tim and all, thanks for the comments.

I got the rear drive off and the splines are bad on both the drive and the shaft. If I am going to fix this, through Bruno's work or otherwise, what else should I check out/fix while I have it apart. I imagine I will need to take off the swing arm to get the shaft free. Are things like clutch replacement a good idea at this point? Anyone know about Bruno's prices offhand?

Tim made a good point about whether or not to fix this. I did get it running quite well after fixing the air leaks, changing the plugs and some fluids. It was running very nicely till this event. I paid $1,200 for this and have put another 200 into her so far. I had purchased this recently to find out if I wanted to get back to riding after being off for many years. The answer is yes and I even purchased a 2009 K1300s which is a blast to ride.

Again I thank you for your comments and any further comments that might help me decide what to do, go ahead and fix this or not, and if I do what else should I consider fixing on the bike at this stage.

Thanks,

Skids

There are various threads on how to lube the driveshaft which can help but the shaft just clicks into the sidearm, or to be more exact, the U joint on the other end of the driveshaft clicks onto the output shaft of the trans. Should be able to grip the exposed end of the driveshaft with vise grips and tap it out with a hammer.

I'm not an expert but I would also remove the trans to inspect the clutch hub splines and trans input splines. You can clean them up and lube them while you're in there. Also can replace the rear main seal, the O ring on the clutch housing thing, or some other seals I'm sure I'm missing. Replace the swing arm bearings if needed. Replace the swingarm boot if needed too.

rbm · « **Reply #10 on:** January 10, 2016, 08:32:19 PM »

Quote from: Skids on January 10, 2016, 06:10:39 PM

Anyone know about Bruno's prices offhand?

Should be in the neighbourhood of $200 plus shipping for a new spline collar with grease cup. Picture below of Bruno's work on my old K100 drive shaft.

Skids · « **Reply #11 on:** January 10, 2016, 09:02:56 PM »

Robert,

Thanks for the quick response. Good to know and helps with my decision to go ahead.

Skids · « **Reply #12 on:** January 14, 2016, 05:28:29 PM »

Motobrickers,

On getting the rear drive and shaft rebuilt on my 1987 K100, I found that Bruno is out for health reasons for at least 6 months. He is a very kind gentleman. He mentioned Hansens BMW in Oregon, and after speaking to them I found that they will repair the splines on the rear drive, but not the drive shaft. They would need to order a replacement drive shaft. After discussing the cost of this I asked if there was anyone else they knew of that did a repair similar to Bruno's. They mentioned that there was someone in British Columbia who did this repair, but could not remember the name.

I'm wondering if there is anyone on our forum who might know of someone in British Columbia or elsewhere who does the rear drive and drive shaft repair, that is replacing the splines on both. If I can't get the price down a bit I will probably be selling -hopefully- a parts bike.

Thanks for any comments.

Skids

Martin · « **Reply #13 on:** January 14, 2016, 05:55:36 PM »

Shame to scrap a good K, have you tried to source second hand output shaft, or even a second hand gear box.
Used parts seem to be cheap in the US, I have a mate who has quite a collection of parts including two boxes.
Unfortunately he won't sell and the freight to US is a killer. Don't give up just yet there has to be parts out there.
Good luck Martin.

Skids · « **Reply #14 on:** January 14, 2016, 06:07:12 PM »

Martin,

Thanks. I've been looking at some used parts on eBay and what and I may have found some possibilities. Do you happen to know if the rear drive and shaft from a 1986 K100 would fit a 1987 model? Or where to find this info.

Thanks again,

Skids

Martin · « **Reply #15 on:** January 14, 2016, 06:23:35 PM »

Skids you need to count the number of splines, I believe they changed 2/86. But if you are changing the drive shaft and output shaft as a pair they will fit. The later shafts are more durable. If you need to check parts compatibility just type in BMW K100 Parts Fiche on your computer there are lots of sites.
Regards Martin.

rbm · « **Reply #16 on:** January 14, 2016, 07:11:54 PM »

A 1986 K20 drive shaft should fit a 1987 K100 final drive. The K16 drive shaft (26111241630) was replaced in 3/85 with the K20 (26111454063).

Martin · « **Reply #17 on:** January 14, 2016, 10:30:09 PM »

Sorry about the wrong dates for changeover. I just go to A&S BMW Motorcycles Parts Fiche and it shows Z16 up to 02/86 and Z20 from 02/86. RBM probably has a better source.
Regards Martin

Brad-Man · « **Reply #18 on:** January 15, 2016, 09:58:09 AM »

You might contact Hansen's in Medford, OR about the possibility of them repairing them...

http://www.hansensmc.com/repair-your-bmw-with-certified-technicians--service

Skids · « **Reply #19 on:** January 15, 2016, 12:49:05 PM »

Thanks Brad-man. I spoke to Hansen's and they will repair the rear drive spline but not the drive shaft. They would use a new drive shaft and give me 20% off on the shaft if they fixed the drive. All that would be in the range of $5 to $600. So I am looking for a way a bit les expensive if possible. Otherwise I may need to see if someone is looking for a good parts bike. The engine and all are very strong.

Thanks,

Skids

The Mighty Gryphon · « **Reply #20 on:** January 15, 2016, 01:28:01 PM »

These guys claim to do driveshaft and final drive repairs. They are located in Virginia.

http://www.largiader.com/shop/benchwork/

You can purchase a driveshaft spline repair part from Moto-Bins:

https://www.motobins.co.uk/bmw-parts.php?model=K%20Series&bikeref=K100

With their part, you take you shaft to a machine shop where they machine the old shaft to receive the new splines and then weld the part onto the old shaft.

Skids · « **Reply #21 on:** January 15, 2016, 08:46:05 PM »

Mighty G,

Thanks for the information. Seems like a good possibility to follow up on - I will do that!

Skids

BermudaBrick · « **Reply #22 on:** January 20, 2016, 01:28:33 PM »

Skids:

I'm very interested on your final solution as I believe I'm in the same boat as you are. I opened up my final drive and found that the drive shaft splines are pretty chewed up (see attached pictures). Chris Harris said I had about 10k left on the drive shaft but 20k on the pinion splines.

If I went with the motobins solution or got a new drive shaft, what does that do to the already-worn final drive splines? Is mating new with old a bad idea? And what about getting a used (but not as worn) drive shaft? Will I be extending the life of the the drive train or will I be causing more harm than good?

Thanks!

TimTyler · « **Reply #23 on:** January 20, 2016, 01:42:10 PM »

I bet you have more than 10k left unless you're a really aggressive rider. You should clean all that crud out of both splines and post more pics.

Definitely keep you eye out for a replacement shaft and final drive. Get some good lube on those splines too.

BermudaBrick · « **Reply #24 on:** January 20, 2016, 01:46:08 PM »

Thanks for the reply, Tim. I have Guard Dog Moly for the drive shaft and pinion splines and I should be receiving some Staburags this week for the transmission/clutch splines.

What do you think about mating another used shaft to the pinion splines? Is that a good idea? There is a 1991 K75RT drive shaft on ebay right now that looks tempting: http://www.ebay.com/itm/Bmw-91-K75-Driveshaft-/252255437146?hash=item3abb98815a:g:IIgAAOSwGotWnGIn

But I'm unsure if mating that with my final drive would be a good idea...?

Thanks.

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Author Topic: 1987 K100LT went "klunk" and no power to the rear wheel (Read 17175 times)