[Devante]

Hey guys,

So I went to go do my first oil change on my 600-mile 2016 Continental GT.

Long story short, all four bolts on the bottom caused damage. Both drain plugs and one of the filter-screen plate stripped the engine threads completely. I can't re-screw the bolts back in now. There's nothing catching onto the bolts now. The thread on the bolts look perfect. The other filter-screen plate bolt broke off inside.

A mechanic friend says it's because of them screwing it in as hard as they could with no regard to torque specs or anything.

I have no idea what I'm going to do now. It's been one thing after another with this bike. I got it 3 months ago brand new.

What can I do, guys?

[Bert Remington]

Find a shop with long experience and excellent reputation for helicoil installation in cast aluminum, then truck your motorcycle and oil change kit there.  Expect to pay $200.  I've had excellent experience with helicoil albeit for American-made after-market parts.  I'm considering preemptive installation for my 2016 UCE.

[mattsz]

1st oil change on a brand new bike?  Never had those bolts out before?  This seems like it should be a textbook warranty repair...

[Bilgemaster]

1st oil change on a brand new bike?  Never had those bolts out before?  This seems like it should be a textbook warranty repair...

Indeed. Were it me, I might insist not merely on some helicoil "patch job", but an entirely new (not refurbished) engine, since I would have real concerns that those drain plugs were most likely NOT the only bits bolted on by Ramesh the Trainee on the line with his pneumatic driver mistakenly set to "tighter than a Scotsman's billfold" (with apologies to Blairio), or merely that the case's casting was faulty. After all, one stripped bolt hole might be a case of simple bad luck, but FOUR?

Unless, of course, YOU gave those bolts the extra heave-ho putting them back in. Then it's on you.

[tooseevee]

Hey guys,

So I went to go do my first oil change on my 600-mile 2016 Continental GT.

Long story short, all four bolts on the bottom caused damage. Both drain plugs and one of the filter-screen plate stripped the engine threads completely. I can't re-screw the bolts back in now. There's nothing catching onto the bolts now. The thread on the bolts look perfect. The other filter-screen plate bolt broke off inside.

A mechanic friend says it's because of them screwing it in as hard as they could with no regard to torque specs or anything.

I have no idea what I'm going to do now. It's been one thing after another with this bike. I got it 3 months ago brand new.

What can I do, guys?

              'Scuse me, but I'm confused 

               Are you saying all these threads were stripped (and a bolt snapped) at the factory and that you didn't know it until you screwed them back in? Did they leak?

                 

[Guaire]

Indeed. Were it me, I might insist not merely on some helicoil "patch job", but an entirely new (not refurbished) engine, since I would have real concerns that those drain plugs were most likely NOT the only bits bolted on by Ramesh the Trainee on the line with his pneumatic driver mistakenly set to "tighter than a Scotsman's billfold" (with apologies to Blairio), or merely that the case's casting was faulty. After all, one stripped bolt hole might be a case of simple bad luck, but FOUR?

The whole batch over torqued?! I agree. Looks like an assembly line created problem.

[KD5ITM]

First of all, by 600 miles you should have already had one other oil change but that's neither here nor there. The engine block is aluminum cast, it can be retaped but no promises that is going to fix the issue. Your best bet is to find a helicoil set that will work with the bolts as long as they're not stripped out otherwise you would need to replace those as well. Drill the bolt holes per the instructions with the kit and then install the Helicoil. I would take some fresh oil and run it through the engine block and drain it out every drain hole to get all of the metal shavings out. Run the oil back through a paint filter and then back through the engine to flush out everything. I would do that two or three times to make sure all the metal shavings come out of the engine from the drilling process. Some blue high temp Loctite will be your friend.

As far as torque specs, I found when I first got the bike before I start writing it that most of the bolts weren't torqued tight enough. Especially the engine mount bolts and the rear shock mount bolts. I would say probably 90% of the bolts weren't tight enough. Looking at some of the YouTube videos of the factory, they use a lot of air tools to screw in all the bolts. Looking at the video, and the way they do it, it's very easy to cross thread the bolt. Some of my Allen head bolts are slightly rounded off where an allen wrench can't grab the bolt to loosen or tighten it. I guess it's safe to say is that what India assumes is good quality control is subpar as far as American Quality Control goes. I've always said, good decent quality control would make these bikes a lot more user-friendly and a lot more desirable and sales would probably rise in the American Market. From what I've gathered from non Royal Enfield Motorcycles is that they assume from what they've heard that the bikes aren't of good quality. Which is kind of a shame.

[KD5ITM]

And yes, if it's a 2016 model, this should definitely be a warranty issue.

[Arizoni]

If the bolts were over-torqued by the factory to the point that the factory stripped the threads out of the aluminum, all of those drains would have leaked like a sieve ever since day one.

I didn't see anything about leaking drain plugs or the oil filter screen plate leaking before this oil change was attempted.

Looking at the original post,

"...
Long story short, all four bolts on the bottom caused damage. Both drain plugs and one of the filter-screen plate stripped the engine threads completely. I can't re-screw the bolts back in now. There's nothing catching onto the bolts now. The thread on the bolts look perfect. The other filter-screen plate bolt broke off inside...."

(underline added)

Note, he says the four bolts caused the damage.

To my way of thinking that means he either cross threaded them and wrenched them in or he did not use a torque wrench and he simply over-tightened them with a wrench.

Likewise, "the filter-screen plate bolt breaking off inside" sounds like a typical case of over-tightening the bolt.
  Those small bolts on that filter screen and on the oil filter cover are only supposed to be torqued to 4 lb/ft of torque.  That's almost nothing.  In fact, when I'm tightening those little cover bolts, I'm always surprised when my torque wrench clicks, telling me the torque has been reached.

As it stands now, if I was the dealer I would chalk it up to user damage which the warranty would not cover.

That leaves having Heli-coil's or similar screw thead insert's installed by a professional, the only easy option.

Sorry to be such a grump but this is the way I see it.

[longstrokeclassic]

My AVL engine had the drain bolts screwed in at the factory with some green thread compound. The first time they were removed both the green compound and the threads in the casework came out at the same time as the drain bolts.
This was factory assembly line 'quality' pure and simple, nothing else. My threads were ruined inside the factory during assembly.
Considering the number of 'quality' issues I've had to rectify on my latest Enfield it wouldn't surprise me in the least that this level of quality control is still alive and well in the bowels of Chennai. Yes quality has vastly improved over the last 24yrs  that I've owned numerous Enfield motorcycles, but it's still sadly lacking.   

[KC1961]

Recently, when replacing the "starting to fall apart" primary chain, I discovered that the chain tensioner bolt had been fitted cross threaded. Makes me wonder what other badly assembled pieces I'll find somewhere down the line.

[gizzo]

Thanks,  you just reminded me to get on and change that chain.  Been sitting on the bench for the last month...

[tooseevee]

If the bolts were over-torqued by the factory to the point that the factory stripped the threads out of the aluminum, all of those drains would have leaked like a sieve ever since day one.

I didn't see anything about leaking drain plugs or the oil filter screen plate leaking before this oil change was attempted.

Looking at the original post, (underline added)

Note, he says the four bolts caused the damage.

To my way of thinking that means he either cross threaded them and wrenched them in or he did not use a torque wrench and he simply over-tightened them with a wrench.

Likewise, "the filter-screen plate bolt breaking off inside" sounds like a typical case of over-tightening the bolt.
  Those small bolts on that filter screen and on the oil filter cover are only supposed to be torqued to 4 lb/ft of torque.  That's almost nothing.  In fact, when I'm tightening those little cover bolts, I'm always surprised when my torque wrench clicks, telling me the torque has been reached.

As it stands now, if I was the dealer I would chalk it up to user damage which the warranty would not cover.

That leaves having Heli-coil's or similar screw thread insert's installed by a professional, the only easy option.

Sorry to be such a grump but this is the way I see it.

             I hafta say that I've got your back here. My immediate impression as soon as I read his post was that this just does not make sense (as I said on June 3).

             They would have leaked from the get-go and especially the broken bolt story just does not make sense- all of a sudden discovered during an oil change? No.

              That's the way I see it.
 

[Richard230]

Perhaps the initial 300-mile servicing was performed by the OP's dealer and the damage was done then and there by their servicing mechanic. After all, how many shop mechanics actually use a torque wrench when performing normal servicing, especially when they probably work on a number of different brands, models and years of motorcycles - most of which have better fasteners and metal quality than use by RE? That makes even more sense to me then that the over-torquing was done during assembly at the factory, where hopefully they are using torque-calibrated air tools at each assembly station.

[tooseevee]

Perhaps the initial 300-mile servicing was performed by the OP's dealer and the damage was done then and there by their servicing mechanic. After all, how many shop mechanics actually use a torque wrench when performing normal servicing, especially when they probably work on a number of different brands, models and years of motorcycles - most of which have better fasteners and metal quality than use by RE? That makes even more sense to me then that the over-torquing was done during assembly at the factory, where hopefully they are using torque-calibrated air tools at each assembly station.

              Reread his first post.

              He says he bought it brand new.

              He says this was the FIRST oil change.

              He does not say he went to a dealer to do the oil change.

              And he does not blame a dealer or a shop. He blames the factory.

              That says to me he did his own oil change. Otherwise he'd be blaming a Dealer or some bike shop.

               Sorry. It just does not ring true that the bike came from the factory with all this damage (and didn't leak all over the place).

[Richard230]

I did read the first post, I just didn't quite believe it.  If all of the bolts were stripped then the oil should have been leaking out of the bolts and covering the sump with oil and maybe his tire, too - unless someone at the factory realized their mistake and used some sort of glue, sealant, or epoxy on all of the bolts before filling the sump. 

[Devante]

I did read the first post, I just didn't quite believe it.  If all of the bolts were stripped then the oil should have been leaking out of the bolts and covering the sump with oil and maybe his tire, too - unless someone at the factory realized their mistake and used some sort of glue, sealant, or epoxy on all of the bolts before filling the sump. 

Hey guys, thanks for all of the replies.

So you're saying if either the bolt or the engine casing has its threads stripped, there would be a leak?

The warranty option is going to be hard because the nearest dealership is an hour and a half away (Bakersfield, CA) and that's a long way to haul a bike just to have them blame it on me since I was doing the oil change myself.

I'm considering my options right now. Leaning toward re-threading them to one size up after drilled that one bolt out.

I'll update!

[Arizoni]

I don't think re-threading them "one size up" is a good idea.

There is a limited amount of material around the bolt hole in the cover plate and enlarging it for a larger bolt will weaken the entire area.
There may also be a space problem for a larger hex head plug in the drain hole(s) location.

Installing steel screw thread inserts not only allows the use of the existing bolt size along with the existing clearance hole in the cover but by replacing the aluminum threads with steel, the new threads will be much stronger.

If you do decide to install Heli-Coil's or similar screw thread inserts be sure to get the "free running" or "non-locking" type of insert.
Heli-Coil inserts come in both free running and locking types and you do not want to use locking threads in locations that need to have the bolts or plugs removed for common maintenance.

[Devante]

I don't think re-threading them "one size up" is a good idea.

There is a limited amount of material around the bolt hole in the cover plate and enlarging it for a larger bolt will weaken the entire area.
There may also be a space problem for a larger hex head plug in the drain hole(s) location.

Installing steel screw thread inserts not only allows the use of the existing bolt size along with the existing clearance hole in the cover but by replacing the aluminum threads with steel, the new threads will be much stronger.

If you do decide to install Heli-Coil's or similar screw thread inserts be sure to get the "free running" or "non-locking" type of insert.
Heli-Coil inserts come in both free running and locking types and you do not want to use locking threads in locations that need to have the bolts or plugs removed for common maintenance.

Wish I would have checked earlier. I went ahead and tapped them all up a size.
Seems to be working fine, though, although I have a tiny leak from the main bolt. Not enough to drive but enough to have oil showing on the top of the bolt.
Don't know if I need to tighten it even more or what.

Is it still possible to heli-coil these using the new threads I made? I kind of thought the heli-coil was a weaker connection since now you have a removable piece between the bolt and the engine.

[Arizoni]

Be very careful about torquing bolts that are engaging aluminum parts.

Aluminum is a relatively weak material when compared with steel and if the torque is too high it will rip the threads out of the aluminum.
If it were mine at this stage of the game I would put a thin layer of Permitex Ultra Black gasket compound on the leaking bolt after removing all traces of oil and before screwing the bolt in.
Ultra-Black is a special type of silicone sealer that will not harm the aluminum and it is oil-proof.
Being a silicone rubber type of sealant, its shear strength is low so it will not try to lock the bolt in place.  It should still be easy to remove the bolt the next time you need to change your oil.

As for the strength of Heli-coils, they are stronger because first, they are made out of steel.
Second, because the external threads are larger than the original threads they are engaging more thread area in the aluminum part.

More area gives a larger amount of material to distribute the load thru so even though the strength of the aluminum is the same any given place in the joint will need to resist less force.

As for having enough material to install a Heli-coil that is the same as the old size, I think your out of luck.

The tap for a Heli-coil and the threads it makes is a bastard size, usually somewhere between the size of the old thread and the next standard size up from the old size.
Because you have already tapped the holes to the next standard size I really doubt there is enough material in the hole to install a Heli-coil of the old size thread.

[gizzo]

These keyserts might work better than a helicoil? They need a bigger hole anyway, so it might not be too late. They are super strong and lock in positively.  You'd be smart to take the machine to an engineering shop with experience fitting them, though.
https://www.thorintl.com/Keenserts-Keyserts-Keylocking-Inserts.shtml

[Arizoni]

IMO, DON'T use the Keenserts in a oil or fuel tank type of application (like the sump of a motorcycle or cars crankcase).

Notice, they have several steel "keys" that are driven down thru the parent metal's threads.
Those keys, once driven home will create 3 or 4 direct leak paths past the outer threads of the insert.

We used Keenserts on a number of applications on the jet engines I helped to design but they were always used only in places like a flange where the far side of the hole was surrounded by outside air.

While I'm on the issue of oil tanks and the like, it is a good idea to install Heli-coils using a sealant like Hilomar on the outside threads.

Not only will the Hilomar seal the threads against a leak path but it will lock the insert into the hole.

One of the reasons we seldom used Heli-coil inserts on our engines is they tend to unscrew from the parent material when the bolt that is screwed into them is removed if they aren't installed with a thread locking compound of some kind.

[gizzo]

Fair enough. I've had good luck with them. Using where there's a fluid behind them (usually coolant but oil and fuel, too), Stag seems to keep them fluid tight. Anyway, there must be some kind of insert designed for just this problem.

[Bert Remington]

Devante -- repeating what I said last week: "Find a shop with long experience and excellent reputation for helicoil installation in cast aluminum, then truck your motorcycle and oil change kit there."

Like Arizoni said, the outer diameter of a helicoil is a non-standard size.  But I'm pretty sure your situation, while uncommon, is not unique and a "dual helicoil" solution can be fabricated.  For the reasons Arizoni and others identified you should return to the original bolt sizes.

BTW it might not be a "dual helicoil" solution but rather a threaded rod with Red Loctite solution but that depends on your expert and experienced shop.  I don't want to second guess them.

WRT helicoil inserts being weaker or removeable, they are neither.  For instance, Edelbrock as standard practice helicoils all fastener points in their aluminum cylinder heads because the result is stronger than the surrounding cast aluminum.

WRT to using helicoil alternatives, my recommendation is DON'T.  Unless your expert and experienced shop says otherwise.

WRT to prioritization of helicoil installation, my recommendation is place this before any other farkle purchase.

WRT future oil changes, your next investment after helicoils should be a 1/4" torque wrench.  I use the BikeMaster digital torque wrench (https://bikemaster.com/1-4-digital-torque-wrench.html) for all bolts.  I have a 1/4"-to-3/8" adapter for the 19mm rear bolt.  I only use a 1/4" torque wrench because, like Arizoni says, 4 ft-lb comes up real quick on the 8mm bolts and it has the range for the 14 ft-lb 19mm bolt.  Arizoni apparently uses a "click" torque wrench which is probably just as accurate but less expensive so if he has a recommendation go with it.  DON'T buy cheap because they aren't adequately accurate.

My experience with "click" wrenches is they are more accurate if you "warm them up" with a few dry runs before tightening the fasteners of interest.  Do this every time you change the torque setting, especially for the low range of the wrench.  And always return it to its rest position before putting it away.

PS my second favorite track is Buttonwillow.  Once you get your RE sorted I suggest you first visit on a motorcycle day to understand what's happening and then another visit with an open-tracking (ie not racing) group.  Its fun, addicting and it WILL improve your driving skills.  Unfortunately their riding gear requirements are rigorous (ie expensive) so find some buddies your size.

[hpwaco]

Arizoni,   you said that the torque value for the filter cover and screen cover plate bolts is 4 ft lbs.  What is the value for the drain plugs??   The torque value pages in my gt service manual (printed in 2013) doesn't show any of these bolts or drain plugs.   Is this info in the UCE manual?    Thanks,  HP

PS:  how do you convert nm values to ft lbs?

[wildbill]

Aggregate                                     Component                                       Fastener                   Torque Range
Pawl stop plate assy Hex Screw M8 * 23 1 25 2.5
Indexing Pawl Assy Hex nut M6 * 1 (U nut) 1 20 2
Indexing pawl lock nut assy Bolt Pawl,M12 *1.5 -6h 1 10 1
Magnetic Plug assy Magnetic Plug assy,M14 *1.25 1 20 2
Sump Drain Cap Assy Hex flange bolt M5 * 16 2 6 0.6
Hyd. tappet lock pin “S’ bracket assy Hex soc head cap screw M6 2 10 1
Tappet door assy CSK socket head screw M5 *0.8*12 2 4 0.4
Kick starter spring bolt assy Hex Screw M6*16 1 10 1
     RH
Kick starter cover assy Hex Socket Pan head screw M5*12 4 6 0.6
Crankcase FD sprocket assy - 17 Teeth Nut M35*1.5 1 78 8
Pump Assy
Hex Socket Head cap screw M6*25 2 10 1
CSK Socket Head cap screw M6*30 3 10 1
Starter motor assy Hex Socket Head cap screw M6*60 2 10 1
Cam pivot screw assy Pivot M4*0.7 1 3 0.3
Inlet/Exhaust Cam sleeve nut assy Nut M10 * 1 2 20 2
Cam steady plate assy
Hex Socket Head cap screw M6*30 2 10 1
Hex Socket Head cap screw M6*25 1 10 1
Auto chain tensioner assy Hex Socket Head cap screw M6*20 2 10 1
Retainer plate assy Hex Socket Head cap screw M5*16 2 6 0.6
     LH
Box assy for 13 Screws Nut M6*1 22 10 1
Crankcase Starter motor housing assy Hex Socket Head cap screw M5*25 1 10 1
Starter motor housing assy Hex Socket Head cap screw M5*45 3 10 1
Chain Pad nut assy Hex Nut M8 * 1.25 2 20 2
Engine Sprocket & Sprag gear assy Hex flange screw M12*1.25 1 65

Breather plate assy Hex Socket Head cap screw M5*12 6 6 0.6
Pulsar Coil assy Hex Socket Head cap screw M5*16 2 6 0.6
Stator Coil assy Hex Socket Head cap screw M5*30 3 10 1
Inspection screw assy Inspection screw M6*14 * 1.25 1 20 2
RH Cover Oil filter cap assy Hex flange bolt M6 * 1 3 10 1
Breather bolt assy Bolt M12*1.5 1 20 2
Magento Assy Hex Nut M12 *1.25 1 47 4.8
RH Cover assy
Hex flange bolt M6 * 1 * 45 1 10 1
Hex flange bolt M6 * 1 * 70 7 10 1
Hex flange bolt M6 * 1 * 85 2 10 1 LH Cover LH assy Oil Filter plug M18*1 1 20 2 Cover Hex Flanged bolt M6*1 1 10 1
Sprak plug assy M14 Spark Plug M14( WQR8DC) 1 25 2.5
Sprak plug assy M10 Spark Plug M10 (UR6DC) 1 13 1.3
Cylinder Head Nut M8,Grade 10 2 30 3.1
Cylinder Cylinder head assy Flanged Hex nut M8*1.25 1 30 3.1 Head Inlet/Exhaust Rocker bearing assy Hex Socket head cap screw M6*55 4 10 1
Rocker cover assy
Bolts M7*1 3 14 1.4
Hex head screw rocker cover mounting 1 14 1.4 (seal bolt) M7*1 Gear Pivot upper bearing assy Hex Socket head Head cap screw M6*16 1 10 1 Train Pivot lower bearing assy Hex Socket head Head cap screw M5*40 1 6 0.6
Engine
Rear mounting bracket assy Hex Nut with Nyloc insert M8 2 25 2.5
Front munting bracket assy Hex Nut with Nyloc insert M8 2 25 2.5
Clutch Clutch Assy Hex Nut with Nyloc insert M 16 *1.5 1 47 4.8

[tooseevee]

Aggregate                                     Component                                       Fastener                   Torque Range
Pawl stop plate assy Hex Screw M8 * 23 1 25 2.5

             I guess I'm lucky that Pete Snidal's manual has all the torque values for my AVL, but I've just got to ask: What exactly does 23 1 25 2.5 mean?

 

[Devante]

Hey guys. An update:

Drilled the M5 bolt out (or was it M4?). The one that goes in that little plate in the middle with the small cylinder screen inside.

Anyway drilled that out, tapped both of those holes to M6.
Tapped the front drain plug to M10.
Tapped the back to M16.

Looked inside with a flashlight, the threads looked good.

Bought cheap oil and ran it through to make sure any metal shavings were out. Then put more oil and ran it around the block a couple of times and did another oil change to make double sure there was no metal from the rethreading. Then put my final oil in.

3 of the four were leaking.

I removed the bolts and put black silicon gasket maker on them.

While putting them back on, I notice the front drain bolt threads were all jacked up. I was suuuuuper careful putting these bolts back on. Also, putting the bolt into the hole where the broken one had to be drilled out... well again super careful but I could feel it start stripping with minimal effort after hand tightening. I left the bolts to set the silicone for 24 hours.

I also noticed some of the metal threads inside the oil that I drained.

Boy what a mess.

It's been a few days and everything seems fine. No leaking, no bolts falling out ha!

I'm now trying to decide if I should Helicoil the front drain plug and the hole that had the broken bolt in it or save it until my next oil change.

[hpwaco]

Wildbill,  thanks, that's A LOT of good information.  Just wish I could print it.   Cheers,  hp

[Arizoni]

tooseevee

To decipher the information in the chart, for the magnetic drain plug which reads
Magnetic Plug assy Magnetic Plug assy,M14 *1.25 1 20 2

 the M14*1.25 is the thread size.  It is a 14mm X 1.25 pitch thread.

The following 1 indicates there is one of them

The following 20   2 is the torque, first in Newton Meters and finally in Kg-M so the torque is 20 Newton Meters or 2 Kg-Meters

I don't know why we need both because Newton Meters are just 10 times Kg-M.

To convert Newton Meters to Pound/Foot values multiply the NM value times .738.

That makes the torque for the main drain plug 20 NM X .738 = 14.76 lb/ft

To answer the question about the 4 lb/ft torque on the little filter cover bolts, yes, that information came from the Royal Enfield Service Manual.

It doesn't show the forward drain plug that was added around 2014 but if the threads are smaller than 14mm (.551 inches) the torque would be less than 14 lb/ft.
I would guess something around 10 might work?

[hpwaco]

Arizona,   thanks for the torque info - will write it down.    As mentioned my gt service manual leaves a lot to be desired in many areas.  Cheers, hp

[Bert Remington]

Arizoni -- for the front drain bolt I used 8 ft-lb.  No leaks.  Thanks much for providing torque values for this fussy fragile engine.