Stripped drain plug threads $#^!!

[Canuck750]

I was taking a look at my 750S with plans on getting it on the road this spring, a patch of oil was sitting under the bike, turns out the transmission drain plug is leaking, I put a 17mm socket / ratchet on the plug and gently turned the drain plug tighter ... and then the inevitable it just stripped!    DAMN

Rather than fitting a helicoil I thought I would try my luck with an insert, having to work from underneath the bike I thought I might get better results with an insert, anyone used these before?



This is for a 10mm drain plug, the insert has to be tapped to M14 x 1.5 (12.5mm drilll size). Once wound in with the insert tool the spikes are tapped into the cut threads of the aluminum, locking the insert in place

Not a great place to work, off with the mufflers and exhuast cross over, lift the bike way up in the air so I can get a drill into the drain hole



ThenM14 x 1.25  tap by hand, trying to get as straight as possible, I only get one shot at this, then thread the insert in with a dab of locktight on the threads to ensure a seal



After tapping the tangs in (with the tool and a brass hammer),  It seems to have worked well, a new fiber washer on the drain plug and no more leaks, sounds easy but it took an afternoon

[Scout63]

Seems like a great solution. Did the bike swing a lot when you were drilling or inserting the insert?  Also great pictures.

[Canuck750]

Seems like a great solution. Did the bike swing a lot when you were drilling or inserting the insert?  Also great pictures.

The front wheel was strapped down into the lift table wheel chock, rear end hanging from overhead crane. I have to admit not being comfortable holding a 3/8” drill with a 12.5mm bit cutting into the aluminum transmission case! Very slow drilling and the bike remained steady.
I ran a litre of lube through the case to make sure I got any swarf out. Sure would have been easier with the transmission out of the bike but this was worth a try.
I think for most similar types of thread repair I am going to use these inserts, I have mixed luck with helicoils where the fasteners are repeatedly removed.

[lucky phil]

The front wheel was strapped down into the lift table wheel chock, rear end hanging from overhead crane. I have to admit not being comfortable holding a 3/8” drill with a 12.5mm bit cutting into the aluminum transmission case! Very slow drilling and the bike remained steady.
I ran a litre of lube through the case to make sure I got any swarf out. Sure would have been easier with the transmission out of the bike but this was worth a try.
I think for most similar types of thread repair I am going to use these inserts, I have mixed luck with helicoils where the fasteners are repeatedly removed.

That looked like a tricky job, location on the transmission wise. Timeserts are a way better solution than Helicoils but in that situation without the trans removed probably not. Did you apply any thread sealer to the insert?

Ciao

[Loop Tonti EV]

Good job of meeting that challenge.
One point that I might ad is: did the insert finish flush with the
Inside of the case? If the insert protrudes further in then totaly
draining the fluid would not be possible. I'm not criticizing, you
Did a great job, just pointing this out.

[pressureangle]

I'm with Lucky Phil, you've used a 'Keen-sert' here; they're heavy-duty and a wonderful product, but I'd rather have used a 'Time-sert' which doesn't have the pegs up the side. Since the washer makes the actual seal, it probably doesn't matter if the threads weep a bit.

[Chuck in Indiana]

anyone used these before?

A few hundred, probably..  They are standard tool room stuff. Work good, last long time.

[czakky82]

I should pre-emptively do this on my project….

[Scout63]

Dave Richardson says to helicoil all gearbox plug holes if the gearbox is apart.  I did it in my G5 resto but was never comfortable drilling into the case. Doing it upside down and hanging makes Canuck the Ginger Rogers of MC techs.

[pat80flh]

If you're in a pinch most decent auto parts store will have a spark plug rethreading kit, which comes with 3 different lengths of inserts

[BMCMOTO]

I have used both Keen and Time serts and of course heli-coils over the years, all seem to work well with heli-coils only used in more accessible places as they sometimes unwind. I have never had a Time or Keen sert failure (knocking wood) yet. Both Time and Keen seats get loctited.

Brian

[Antietam Classic Cycle]

Two things: 1) The original drain and level plugs are too short - only engage a few threads and thus strip those threads fairly easily. I make longer drain and level plugs that utilize all of the available threads. 2) Instead of aluminum or fiber sealing washers, use "stat-o-seal" or "dowty" type washers which required much less torque to seal properly.   

[blackcat]

Two things: 1) The original drain and level plugs are too short - only engage a few threads and thus strip those threads fairly easily. I make longer drain and level plugs that utilize all of the available threads. 2) Instead of aluminum or fiber sealing washers, use "stat-o-seal" or "dowty" type washers which required much less torque to seal properly.

Thanks Charley, good to know.

I had to install a few Timeserts for my CX drain pan and I just removed the tank and side panel then laid the bike down on some soft tarps. Quick and easy.

[Canuck750]

That looked like a tricky job, location on the transmission wise. Timeserts are a way better solution than Helicoils but in that situation without the trans removed probably not. Did you apply any thread sealer to the insert?

Ciao

I coated the insert threads with orange Locktie, should seal the insert threads. The insert was threaded in flush with the case. I used a newer drain plug I had on hand that is longer than the original. I should have installed inserts in all the plugs when I rebuilt the transmission on the bench…. next time!

[Canuck750]

Two things: 1) The original drain and level plugs are too short - only engage a few threads and thus strip those threads fairly easily. I make longer drain and level plugs that utilize all of the available threads. 2) Instead of aluminum or fiber sealing washers, use "stat-o-seal" or "dowty" type washers which required much less torque to seal properly.

Good advice as always. I need to find some of these sealing washers you spoke of, never seen any for sale locally.

[Antietam Classic Cycle]

Good advice as always. I need to find some of these sealing washers you spoke of, never seen any for sale locally.

They aren't always sold under either of those names. I buy mine from McMaster-Carr: https://www.mcmaster.com/93786A175

[moto-uno]

  Having use these thread repair kits , the worst problem I've found ( in Guzzi's) is the very limited quantity of
alloy for the bolt to thread into . Fear of pulling the insert out again , I took the initiative to drill the drain bolt
for safety wiring and never have to worry about a drain bolt loosening .   Peter

[sign216]

They aren't always sold under either of those names. I buy mine from McMaster-Carr: https://www.mcmaster.com/93786A175

Charlie,

Thanks for that tip.  These washers look like a real improvement over the usual copper/alum ones.  Do you know if Napa or similar walk-in place has anything similar?

Joe

[Canuck750]

  Having use these thread repair kits , the worst problem I've found ( in Guzzi's) is the very limited quantity of
alloy for the bolt to thread into . Fear of pulling the insert out again , I took the initiative to drill the drain bolt
for safety wiring and never have to worry about a drain bolt loosening .   Peter

Yes indeed, the drain plug bolt length is only 8mm, and the thread pitch is very course at 1.5 mm. After the washer is included the available thread length is hardly 7mm, not a good combination. On the other hand the transmission fluid is rarely changed, the drain plug will probably only get removed once or twice in the next ten years.

[Antietam Classic Cycle]

Charlie,

Thanks for that tip.  These washers look like a real improvement over the usual copper/alum ones.  Do you know if Napa or similar walk-in place has anything similar?

Joe

Don't know, I've never looked. I just buy them in packs of 10 from McMaster-Carr. Guzzi used them on later bikes, so MG Cycle has them.

[Canuck750]

Don't know, I've never looked. I just buy them in packs of 10 from McMaster-Carr. Guzzi used them on later bikes, so MG Cycle has them.

I see Fortnite had them listed as Drag Specialties 3/8” Banjo Bolt Sealing Washers - package of 10, just over $10. I think I need to order a package.

[lucky phil]

Don't know, I've never looked. I just buy them in packs of 10 from McMaster-Carr. Guzzi used them on later bikes, so MG Cycle has them.

Guzzi use 16mm ones on oil cooler fittings and crankcase vent hoses on V11's and Centauros. You can buy a box of assorted ones on ebay fairly cheap.

Ciao 

[lucky phil]

I bought a Jackal recently that has a seized engine.  I unscrewed the oil plug to drain it.  And unscrewed it .  . .and unscrewed it.  . ..etc . .  .without really looking at it.  I was beginning to think it was stripped and just spinning.  But no, the darn drain plug is longer than a cocktail weenie.   

With the extremes of screw length in mind, Those Dowty-type washers are really thick.  They vary from 3-4 copper washers in thickness.  They work well, used as intended.  I buy them by the baggie in different sizes.  They only require torque enough to seat the center and snug the fastener, since it's the soft, chewy center doing the sealing.  The crunchy outer shell supports the center and restricts the amount that the center can crush.  Some don't do brake fluid, so be sure the composition of the center works for your fluid.  Some won't seal a bad flange -- not enough diameter to the sealing portion.

[/b]

Some won't seal period believe it or not. I couldn't get various different ones to seal the large blanking plug on the Daytona engine sump and reverted back to the standard crush washer which worked fine. Strange. I've been using them for over 40 years on commercial aircraft as well so I'm well versed in them.

Ciao

[Don G]

Canuck: Any good hydraulic fitting supplier will have the steel washer with bonded o-ring sealing washers in stock in a variety of metric sizes. DonG

[Canuck750]

Canuck: Any good hydraulic fitting supplier will have the steel washer with bonded o-ring sealing washers in stock in a variety of metric sizes. DonG

Thanks Don!

[Huzo]

I always lock wire the sump plug on my Norge.
It means you don’t have to butcher them up as tightly as you might feel urged to do otherwise.
Also, the thought of a sump plug coming out directly in line with the rear wheel 12” away, does not bear contemplating.

[Bulldog9]

Two things: 1) The original drain and level plugs are too short - only engage a few threads and thus strip those threads fairly easily. I make longer drain and level plugs that utilize all of the available threads. 2) Instead of aluminum or fiber sealing washers, use "stat-o-seal" or "dowty" type washers which required much less torque to seal properly.

Took the words out of my mouth I've saved many a drain plug by going with a longer plug and thinner washer. I also tend to smear some cruelty on the drain plug threads when putting in. Helps to seal from any drips and also prevents galling or corrosion. This is especially helpful if you have a lot of bikes and aren't changing the gear oil every year or two. I will have to look into the ceiling washers you mentioned never heard of them.

[normzone]

"smear some cruelty" ?

 

[Huzo]

I will have to look into the ceiling washers

They’re right near the rotating fan and the light bulb...

[moto-uno]

  ^   Beet me to it  . Peter