If you like our site, please consider joining our club!
By joining you will help ensure that we can continue to provide this service
JOIN HERE!

Stripped Drain Plug Woes - Second Update

User avatar
Slash2
Posts: 538
Joined: Sat Oct 17, 2015 10:22 am
Has thanked: 1 time
Been thanked: 2 times

Stripped Drain Plug Woes - Second Update

Post by Slash2 »

Doing the 600 mile “break-in” service on my 1984 R80 G/S was going fine until I removed the drain plug for the shaft drive. I noted that the m12x1.5 bolt was stiff coming out and upon inspection realized that the coarse-threaded bolt elected to bring several threads along with it. I’ve had this bolt out once and reinstalled with a new aluminum crush washer to below spec torque but it seems the soft aluminum threads and the hungry coarse steel threads of the drain bolt were no longer getting along. Ugh.

So I’m faced with a few decisions.

1. Attempt to drill it out on the bike, flush the shaft with kerosene to hopefully remove all the bits of aluminum and then install a helicoil. $80 - Fast

2. Buy the tools to remove the pinion nut and partially tear the FD down to allow the work to be done on the bench and eliminate the potential for contamination from any leftover bits of metal. Finding a way to secure the FD to employ a drill press will be tricky. $200-$300 A week or 2.

3. Send the FD out to Ande @ Barrington to rebuild, replace the large ring gear bearing, and the pinion double row ball bearing, fresh seals and of course drill, tap and timesert the drain threads. $500-$1500? 2-3 weeks at best.

If I elect 2 or 3 I’m faced with the bike being non-op for some of the last beautiful riding weeks of autumn which is a real drag after spending nearly a year restoring this motorcycle to service but so it goes. I guess I can slum it on my R69S or another of my older bikes in the meantime.

Please give your honest input. Of course cost/time is a factor but I’m also the sort of mechanic/rider who prefers to do it right and do it once. The FD isn’t currently leaking so the current seals seem ok but I do have a very minor tick of play which would likely be resolved with the replacement of those bearings.

Thanks!
Last edited by Slash2 on Tue Dec 20, 2022 10:57 am, edited 2 times in total.
Western Pennsylvanian - Airhead Extraordinaire

User avatar
schrader7032
Posts: 9016
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX
Has thanked: 2 times
Been thanked: 29 times

Re: Stripped Drain Plug Woes

Post by schrader7032 »

Tough call. Doubt that fixing it on the bike will be totally successful...swarf being an issue. There's not a lot of pressure on this bolt from the oil. There are freeze plugs that have a rubber insert that expand when the bolt is tightened down. Might work for a while, but I might like to have a "suspender" using say a large zip tie or hose clamp around the bolt and the rest of the driveshaft. The issue of course, if that plug comes out, you'll have oil on the back tire which is not good.

Maybe something simple until you can lay the bike up for a longer duration?
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

User avatar
Slash2
Posts: 538
Joined: Sat Oct 17, 2015 10:22 am
Has thanked: 1 time
Been thanked: 2 times

Re: Stripped Drain Plug Woes

Post by Slash2 »

Kurt,

I had considered this sort of temporary fix to get me through the end of the riding season and assume it would be sufficient to keep the 150cc’s inside the housing until a more thorough fix could be accomplished. One consideration that I’m concerned with is whether or not any of the threads are already floating around inside the housing. I was able to extract several threads and while gravity is on my side there’s really no way to know what’s inside without getting in there.

If I was on a trip this sort of “bandaid” might be easily justified where as the only reason to keep from properly fixing it now is my general desire to continue riding until the weather turns fully toward winter.

Chris
Western Pennsylvanian - Airhead Extraordinaire

User avatar
schrader7032
Posts: 9016
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX
Has thanked: 2 times
Been thanked: 29 times

Re: Stripped Drain Plug Woes

Post by schrader7032 »

Ah, good point. Maybe a complete fill with gear oil and then some slight pressure to push it out...repeat a few times?? Maybe even pull off the boot at the front and do the flushing from there. I'm guessing the metal would be aluminum? Otherwise, a long stick-magnet could be used to fish out steel.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

User avatar
Slash2
Posts: 538
Joined: Sat Oct 17, 2015 10:22 am
Has thanked: 1 time
Been thanked: 2 times

Re: Stripped Drain Plug Woes

Post by Slash2 »

Yes unfortunately it’s aluminum shavings as the drain is in the final drive housing so a magnet is not an option.

The design of these bolts is altogether baffling to me. A couple of very coarse threads is all that’s there to grab. I can’t think of any reason a fine thread wouldn’t be far superior.

Thoughts?

See attached photos.
Attachments
844C3EF9-E9D6-41EE-A0B6-FD059BAAFAB5.jpeg
B30C7536-9487-4879-87B8-7DCC14669AFC.jpeg
Western Pennsylvanian - Airhead Extraordinaire

User avatar
schrader7032
Posts: 9016
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX
Has thanked: 2 times
Been thanked: 29 times

Re: Stripped Drain Plug Woes

Post by schrader7032 »

How much could you lower the front end of the shaft tube? Remove the rubber boot and then the four bolts holding the shaft onto the output of the transmission. Then remove the swingarm pins. It should dip so that the front is lower than the rear. Could do the flushing that way. Not sure how much the shocks would resist this. Lot of work I guess.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

User avatar
Slash2
Posts: 538
Joined: Sat Oct 17, 2015 10:22 am
Has thanked: 1 time
Been thanked: 2 times

Re: Stripped Drain Plug Woes

Post by Slash2 »

Out of the entire restoration process, getting that drive boot on correctly was the most dreadful part. You couldn’t pay me to take if back off now. Unlike the /2 boots which are comparatively a dream to install, the monoshock model is so stiff and prone to snap back together when drawn apart that the installation process was simply miserable.

Looking at photos of the internals there is barely any margin for error without at least removing the pinion nut and driveshaft coupler. Sounds like option 1. is out.
Attachments
23689462-F3D4-4A74-B068-5435FB8AD46A.jpeg
Western Pennsylvanian - Airhead Extraordinaire

Jim D 5112
Posts: 200
Joined: Fri Oct 27, 2006 3:00 am
Has thanked: 1 time

Re: Stripped Drain Plug Woes

Post by Jim D 5112 »

Find a used low mileage final drive and just replace it.

User avatar
malmac
Posts: 796
Joined: Sun Jun 29, 2014 2:10 am
Location: Toowoomba, Australia.
Has thanked: 1 time

Re: Stripped Drain Plug Woes

Post by malmac »

The tread is in the final drive housing - right.

Take the back wheel off.

Remove the final drive.

If you don't want to do it your self, take the final drive to a machinist who will insert a new thread.
There are several options. There is an option that inserts a metal sleeve and then three triangular pins are driven down to retain the insert.

https://www.nei.com.au/product/kipp-thr ... rts-k0398/
07660-1.jpg
There seems to be room for this approach and there are probably others that are as good or even better.

Clean out the swarf, new gasket probably. Its all back together in a a couple of days max if you can get your local machinist to do it straight off.

My two bob's worth.

Mal
mal - R69s
Toowoomba- Australia

User avatar
Slash2
Posts: 538
Joined: Sat Oct 17, 2015 10:22 am
Has thanked: 1 time
Been thanked: 2 times

Re: Stripped Drain Plug Woes

Post by Slash2 »

Jim D 5112 wrote:
Fri Oct 14, 2022 8:53 pm
Find a used low mileage final drive and just replace it.
This sounds great but the question is where. One of my first moves was to go hunting for a replacement but all I came up with was higher mileage units in mystery condition which sounds like just trading one problem for another.
Western Pennsylvanian - Airhead Extraordinaire

Post Reply