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Stripped Drain Plug Woes - Second Update

sherman980
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Re: Stripped Drain Plug Woes - Second Update

Post by sherman980 »

Chris,
Sounds like things are tighter than they should be, but hard to know without being there. If it is "seal resistance", it should subside very quickly. I'd get the bike up with the rear wheel off the ground (so it can't rock and come down!), start the bike and put it in gear and let it spin the rear wheel a short bit. Listen for nasty noises, etc. and see if the rear drive gets warm quickly. Then check to see if things have loosened up at all. If all goes well, do it a few more times. If it doesn't loosen up some or gets hot, I'd be concerned. If all seems ok, ride it a bit and see if the resistance lessens. It should not be hard to push the bike around the garage/shop.
Thanks.
Chuck S

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Slash2
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Re: Stripped Drain Plug Woes - Second Update

Post by Slash2 »

Hey Chuck,
Thanks for weighing in. This sounds like a rather safe and logical approach. I'll give that a go and report back. In the meantime I've located a working equivalent final drive from an R80ST which is the only unit compatible with the G/S. If my drive does not loosen up after this process, I'll be doing to it what I clearly should have done from the start, fixing it myself. At least this way, my bike won't be laid up any longer either way.
Western Pennsylvanian - Airhead Extraordinaire

Kurt V
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Location: Lincoln, NE

Re: Stripped Drain Plug Woes - Second Update

Post by Kurt V »

I would double check and see if somehow your rear brake didn’t get out of adjustment and it’s causing the drag. Doubtful, but you never know.

As for that drain plug, sometimes the best expert is learning how to do things yourself. No one else is ever going to care as much about your bike as you. Of course, I know that we can’t all become experts at everything. However, if that stripped drain hole had been on my bike, my solution would be one that would probably upset many here. I would’ve just found the next tap size that would cut threads in the drain hole, cut the threads and then purchased a very short bolt that would fit. You could easily find an aluminum washer to fit the bolt to use as a seal. You could put a little Vaseline or wheel bearing grease on the tap to catch any swarf that you create when cutting the new threads. I wouldn’t have been too worried about any of the old aluminum threads having dropped into the final drive. They would’ve been very thin slivers of aluminum and I doubt they would’ve caused any trouble. But, that’s just me talking.
Kurt V
R60/2, R65 LS
1973 Norton 850, 1973 RD 350

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Slash2
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Re: Stripped Drain Plug Woes - Second Update

Post by Slash2 »

Kurt,
The tightness in the final drive was obvious even before I installed it on the bike. Once installed and with the braked adjusted, I can feel the application of the brake when the pedal is actuated and I’m sure it’s functioning normally.

So the moral of the story is if you want it fixed right, either do it yourself or send it to someone who cares about the work that they do. I’ve never shipped out a component in my life and only did so this time due to the nature of the repair AND the encouragement of this group. Live and learn but as for myself, I would not encourage anyone to trust Scottie with their bikes or components but as your mileage may vary, by all means roll your own dice.
Western Pennsylvanian - Airhead Extraordinaire

scottiesharpe
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Re: Stripped Drain Plug Woes - Second Update

Post by scottiesharpe »

Well it's the beginning of 2023 and I'd like to wish everyone a happy near year. I was trying to figure out how many final drives I rebuilt last year and I lost count at around 20, including one sent to us from my old stomping grounds in Pennsyltucky by our friend Chris. Chris mailed us his drive for a thread repair on the shaft drain plug, a repair I've done before. I did give Chris a quote and told him I'd install a timesert. After the drive arrived Chris contacted me several times because my communication with him was lapse. Granted, I am not a good communicator. I don't have a secretary and I after giving up my position as Editor of the Vintage BMW Motorcycle Owners magazine, frankly, I avoid my computer like the plague.

Chris and I discussed the fact that we were going to remove the pinion ring to repair the threads and might as well replace the seal. Well damn might as well replace all the seals while it was on the bench. By this time some time had elapsed and it was clear Chris was concerned about getting his gearbox back in a timely matter. I checked my thread repair insert drawer and found I was out of timeserts. So I installed a heli-coil. As is my custom, I checked the lash, tooth pattern and set the end play on the ring gear to 0.003". We replaced all three seals and buttoned up the drive with gray RTV on the gasket and hylomar on the collar threads and splines.

When Chris received his final drive back, he was concerned that I didn't use a timesert and that the heli-coil was installed crooked. I was a bit shocked that the heli-coil was crooked since we use a fixture to install it. (Chris posted pictures of it earlier.) I wanted to see what was up. I sent Chris a postage-paid shipping label from PA to Scottie's Workshop (with $2000 insurance) and he sent the gearbox back to me.

When the gearbox arrived, we threaded in a drain plug a couple of threads and indeed, it appeared as if the threads were crooked. However, I flipped the drive 180 degrees and the drain plug flopped the other way. It was just the wiggle room in the threads that made it appear as if the heli-coil was crooked. When torqued all the way down, the bolt straightened out properly. But I had promised Chris a timesert and I should not have swapped it out without asking the customer, even though the light torque requirements on the drain plug are well within the capacity of the heli-coil... so I set about removing the heli-coil and installing the timesert. I used my heli-coil removal tool to unspin the heli-coil out and I set in a new timesert with Loktite 609. I faced the top of the timesert and casting with an end mill to assure a good, flat sealing surface for the crush washer.

I repacked and sent back Chris final drive with $2000 of insurance. When it arrived he thought it was tight. I informed him that every final drive I rebuild is tight. You can not spin them by hand.

If the bike is hard to push, there are a few things I'd check, one being that weird piece of rubber on the rear brake shoe spring. That thing can get misshapen and slide out of place and drag.

Chris, please do not worry. You should be out riding around with a smile on your face. (Although I bet the weather in PA is pretty crappy this time of year.) But no matter; I will make this promise to you. Install the final drive. Fill it with good quality GL4. Run it. If it fails within 10,000 miles, I will repair or replace it. Thanks for your business.
Scottie Sharpe, Proprietor
Scottie's Workshop, 3282 E Hwy 4, Murphys CA
Full Service Workshop for vintage and classic BMW Motorcycles http://blog.scottiesharpe.com

strichzwei
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Re: Stripped Drain Plug Woes - Second Update

Post by strichzwei »

Well, good to hear Scottie chime in on this thread.

It appears Scottie acknowledges the poor customer experience (which can happen in any business) and is apologetic, important is that he is willing to make it right with the customer and unequivocally stands behind his work.

S

Somerset West BMW
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Re: Stripped Drain Plug Woes - Second Update

Post by Somerset West BMW »

Re-thread to M14 X 1.5, then easier to fill and you can use a drain plug.

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