M8 Head Bolts Are BREAKING!! Let's Fix It | Shop Talk Episode 27

In this video Mike goes over how Harley M8 Head Bolts are breaking, and our approach to fixing this. We use S&S Head Bolts with this install. Let us know in the comments what you think!
***For our motor build financing options, we offer a 60 day same as cash and we have 12 month, 24 month, and 36 month terms available. Please contact Jamie or Aaron [phone] to either apply or get more information.
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[@patrickharrison2653]

This is why you’ll be doing my motor work when I upgrade my 17 Street glide. Thanks for the info.

[@MoonshineHarley]

Patrick Harrison 👊🙌

[@beardwrench]

@@MoonshineHarley any thoughts on my comment above?

[@MySt0rmy]

As a heavy duty mechanic and retired for 12 yrs and a owner of Harleys it always blows my mind way they waited so long to put in oil spray piston coolers and it's time to make better head gaskets . maybe a fire ring type to stop the back head gasket from going out .diesel engine compression is way higher than gas and with the fire ring type used in MACK i never had a gasket problem .torqe recheck and go up recheck and wait and recheck i never had a come back .motorcycles are still in the dark ages

[@rickalvaro6340]

This is why I rode down from Canada to have my engine work done!!

[@taps_1021]

That's good that your putting it out there for others that might encounter that issue .

[@aninja7628]

I will always respect a video made with artist of the trade details, good job!

[@SQUID_Road_Glide]

I love it. Why this is happening is really a physics equation. So much for the Engineers, experiential wisdom is the 💣. I be building my S&S 129ci w/ Fueling 508 kit. This information will never be obsolete with this design. I’ve dreamed of a MSH bike during COVID. Just not able to go big. I went to Harley’s 120th because Shantell Williams and her husband Cobb believed in me, three month after purchasing my Glide. Now I’m prepping for Milwaukee again but this time I’m pushing through to Sturgis. MI take delivery on my build this month; S&S 129ci Kit S&S Head Bolts and Cylinder studs kit S&S Roller Rockers Fueling Gorilla Rocker Shafts Kibblewhite Beehive 550 Titanium lift springs T-Man Head Breathers Fueling 7263ST 508 Kit Star Racing Tapped cuffs T-Man No Loss Thunder Max Tuner Currently at tear down stage, and considering sourcing a set of used SE Heads from EBay using my valves. Are 114ci/117ci SE heads the same as 107ci heads? I’m concerned about deck height and piston travel. If I can swing the SE Heads I will try to have them resurfaced with an 11:1 compression ratio. SQUID ET1(SS/SW/MTS) US Navy, Ret. 2020 Fat Boy “Killmonger” 2021 Road Glide “SilverBACK”

[@Dinoxt12]

Good stuff and procedure but I've learned on my second Harley and I'm on my fourth now to leave them stock less headaches exhaust and aircleaner change & tune and that's it .

[@NoName-vz1ob]

I think the increased torque on the M8's (partly due to the increased size of the fasteners themselves) is part of the issue. On the Twin cams the Cometic final torque is 42 lbs I believe and the 90° torque to yield (stock procedure) is started at 15-17lb/tq. On M8 the 90° is started at 25lb/tq while the S&S/Cometic recommendation is 45 lb.

[@rsbharley4766]

Great video Mike thanks for the explanation. Cheers

[@moonshinexxx420]

Ha ha man you had me laughing at the seat with your service manager. You might want to become a comedian that was great.

[@wdurazo22]

97 RK 100k miles still going strong!!!!

[@elephant2012]

Really makes me want to stay in school! Great video and explanation

[@gregorytimmons4777]

Proving that Hod Rodding is a worthwhile pursuit. As it's not just reckless youth Hell bent on destruction but rather the improvement of what industry brings to market in terms of performance and reliability.

[@jeffreyponting9524]

I had the salesman tell me the leave my M8 electra glide standard bone stock to avoid warranty issues. I have except hand grips and passing lights. In the future the S&S head bolts will be a must if upgrades are done. Thanks for the informative video.

[@TheHighestGodisGood]

Love your stuff guys!

[@Changtent]

As a professional mechanic, I have never liked the "low-torque plus degrees rotation" method for torquing a head. Your finding here once again proves there is no substitute to proper "true torque" procedure when torquing a head. And just as you found here, the new head gasket settles & compresses. This is the reason you need to go back and re-torque the head. On industrial diesel engines, we would test-run the engine to operating temperature then re-torque the head while hot (not recommended for Harley, or aluminum heads). This also meant re-setting your valves of course.

[@docholiday1034]

Jim Manson we also never reused headbolts....

[@skorpius752]

I am a certified aircraft mechanic and I find it appalling at how good harley is at releasing new models before the engineering work is complete. For some reason, they can't even manage to get their throttle by wire correct. I have a 2001 Jetta with a flawless throttle by wire system. I guess Harley didn't have the common sense to contract out the design to Bosch!

[@Changtent]

@@skorpius752 "Here hold my beer. We can do it." hahaha

[@oh8wingman]

@@skorpius752 Harley is just doing what Harley has always done. It's called cheap and dirty. The best bikes that Harley has ever offered are the ones primarily designed, engineered, and built by someone else like the V-Rod which was HD's second joint venture with Porsche. (The first was the Nova in the late 70's.) Their customers are not open to change so HD doesn't change. (This is borne out by the HD owners first reaction to the M8 engine. It was too smooth and didn't shake enough.) It will in the end be the cause of their demise unless they can remake themselves as a tech company which is highly unlikely. One of the interesting things that has happened in the last few years has to do with millenials. Millenials don't like to ride bikes and there was a study done to find out why. One of the biggest reasons was they don't like all that shifting, hence the Honda Goldwing DCT. Part of the study was to try to find out what bike a millennial might be interested in and they were overwhelmingly in favour of HD as their first choice based on brand recognition. Harley thought this was great and sold as many bike to millenials as they could. Problem was, they didn't put any money into improving their product with things like a DCT or better reliability. When it came to purchasing their second bike, the few millenials that would ride chose anything but HD products. Too many breakdowns, too many problems, and too many bills to keep them running.

[@gregorytimmons4777]

@@oh8wingman You are absolutely right. My younger brother is a case in point. I ride a Moto Guzzi and about the one and only time i mentioned The VRod he could only criticize it. Try to pinpoint the reasoning behind that attitude and i can only conclude that i didn't realise he was so dense. Also that he would be such a band wagoner. I pretty much concluded that it didn't sound like the traditional Harley, didn't look like it or have the same power curve. In short, it was too advanced for his liking. He didn't appreciate the more balanced, higher rpm characteristics of the V Rod over his 2006 Night train. The DOHC shorter stroke engine did nothing for him. I'm thinking maybe he raced one and concluded that he didn't like that sound pulling steadily away from him and his bike because i have seen the VRod being wrung out and that thing really moved out quickly with a more refined everything.

[@wooddawg4868]

I have always stayed away from upgrade builds, i just change my engine and transmission oils all the time and just ride my bike.

[@josephwilbik4561]

Good to know!

[@mikedanaher3413]

😂😂😂😂😂 love it. “Stay in school.” Great info👍

[@oldninjarider]

Uhhh "everything is better when you touch it!" - Wisdom from Mike

[@Liveharley1]

Enjoyed the video.

[@ruff4413]

Love you guys content keep it up

[@NoName-vz1ob]

🙏

[@TrippHPjunkie]

Great video guys excellent channel ....👍👍👍👍👍

[@cavscout62]

You can’t go wrong doing things the S&S way...

[@grren1782]

Yes. You can. S&S is a shitshow

[@vector6977]

@@grren1782 how so? Be exact.

[@grren1782]

@@vector6977 low tolerance horrible quality control shit show

[@nealamesbury1480]

@@grren1782 well need a lot more specifics.perhaps u should share them if your to be taken seriously

[@PhilipSepulveda]

This used to be common knowledge, its like the new young deisgners for the m8 forgot all the lessons the shovel and evo designers already learned.

[@jackwillson8099]

And all that will change after heat cycle . also hope your using moly lube on the threads & under the head bolts. big difference you'll come to torque faster less friction

[@cavolpert]

Damn, Harley still the driving force behind motorcycle mechanics institute

[@arthurmchugh5184]

That's fuckin funny

[@ihateemael]

what nobody has mentioned is that the low-torque then angular method gives a quick to tighten to yield for single use fasteners.

[@vector6977]

This happened with the early evos too. Been using the S&S sequence for years.

[@NoName-vz1ob]

It happens across all platforms and all manufacturers. They are engineered to be stock. When you exceed what they were originally built for you have to upgrade the components to go with it.

[@RidinDad]

Very interesting

[@MoonshineHarley]

We thought so too

[@TENN12]

Dammit! Dealing with oil transfer issues and now this? That S&S 143 is looking pretty good right now.

[@Logan-or5qw]

That actually makes more sense. Torquing your head bolts 10lbs. at a time. A more even ratio. 😀👍

[@bbgdaddy5198]

Just about every issue I hear about lately points to Harley having issues in the head - first gaskets then bolts. I wouldn't buy an M8 bike unless it either already had the head gasket and bolts replaced or it was cheap enough to afford having that done right away. Thanks for the vid - great info!!!

[@NoName-vz1ob]

@it'sallhappening absolutely.

[@NoName-vz1ob]

If the bike is stock it won't have any of the issues we talk about in our videos. All our videos and the failures we make videos about are on modified engines. The M8's are bad ass platforms. If you buy one and want to get performance upgrades just do a little "checking around" before choosing the shop to do it.

[@jimscycleandautotn8508]

Or grow a a pair and do the motor work yourself 👍

[@dirtym4702]

I don’t know if my builder reused them. How would I know if I have this problem?

[@chrismorris9065]

BEST $500 I spent on a torque wrench!

[@sean8470]

Triumph!!!

[@roncoburn7771]

can you torque the stock headbolts with the cometic mls gaskets like the s@s bolts

[@daleezzell1385]

Is there any advantages to replacing the stock head bolts with S and S on a stock 19 107?

[@jack_mcdoogle2609]

“ I gotta call my mom” 😂😂

[@pmdinaz]

Fantastic information! I personally believe that the difference in head gasket material is what is the major difference. The 'squish' is different

[@NoName-vz1ob]

So do we. And the engines weren't engineered for MLS gaskets so it isn't a "flaw in Harley's design" as Sooo many people love to say.

[@ihateemael]

guys if you recheck after a full heat cycle does it pull down some more?

[@dry509]

Do goldwings have these problems?

[@1550tc]

Mike thanks for video and explanation, just curious does ARP have these bolts ??

[@NoName-vz1ob]

Yes they do. We use the S&S bolts usually for the price.

[@1550tc]

M.V.O _Motorfast thanks Mike for the best tech videos on here !!

[@scottbittner2933]

Enjoyed the video Mike, are you experiencing bolt breakage using Screaming Eagle upgrades or non OEM?

[@NoName-vz1ob]

Non OEM. We are adding more compression than the Screamin' Eagle "kits" and using thinner head gaskets.

[@bradyhaggard4672]

Does this problem exist in current models

[@twobeagles1365]

Good video Guys, Thanks for sharing.

[@potato7600]

I just had a stage 4 done to my 2018 m8 and it has snapped the camshaft bolt twice any idea why

[@MoonshineHarley]

Something isn’t happy. We have never experienced that failure. We have seen our share but not a broken cam bolt.

[@jimbeam4111]

Isn’t that considered a soft joint because of the gasket? If it is the bolt will relax 30-50% rather quickly. Kind of odd usually in manufacturing they go to a snug tq and then tq to angle with a final tq in a tolerance zone.

[@NoName-vz1ob]

That is what we are thinking is causing the issue. The lead/graphite gaskets provide much more relief vs. the MLS metal gaskets.

[@thakery5720]

I don't have an M8 so I am not familiar with Cometic gaskets for them, but on both twin cams and sporties Cometic recommend a five step sequence (six if you include the initial finger tightening) 0f 9, 14, 22, 35 and finally 42ftlbs. The gaskets are the same type - MLS - and surely they (Cometic) specify a sequence ? I have even re-used Cometic (and similar) MLS gaskets three or four times with zero problems experienced and the cranking pressure of my sporty is over 230PSI...... can't test the twincam as it has easy start cams but the static comp. ratio is 11.5 : 1.....

[@NoName-vz1ob]

I think the increased torque on the M8's (partly due to the increased size of the fasteners themselves) is part of the issue. On the Twin cams the Cometic final torque is 42 lbs I believe and the 90° torque to yield (stock procedure) is started at 15-17lb/tq. On M8 the 90° is started at 25lb/tq while the S&S/Cometic recommendation is 45 lb.

[@thakery5720]

@@NoName-vz1ob I didn't realise that the threads were bigger diameter - so higher torque is explained, but my comment was more about the five step sequence with Cometic gaskets on earlier models - I am sure it is similar on M8's. Comparing stock 'compressable' gaskets with solid MLS types is a nonsense anyway- stock gasket are crap anyway !

[@jasoningle43]

So does the HD warranty cover this issue if after a HD stage 3 kit is installed??

[@jamielima5315]

Jason Ingle If you have all the Harley approved parts including SE tuner, than YES. Remember we Moonshine Harley-Davidson warranty our motor builds that are done with almost any combination. We believe in what we do. Call us if you have any questions and ask for Aaron or Jamie.

[@jonmarteney7092]

Just curious, do the metal gaskets need any sealant or so you install them dry?

[@NoName-vz1ob]

Clean and dry.

[@Gen-X702]

This is why I have not bought a new Harley the Milwaukee eight seems to have a slew of problems they keep popping up it'll probably be a few years before I even look into getting one hopefully by then I'll have worked out all the flaws

[@NoName-vz1ob]

Slew of problems?

[@america1723]

They are one time use only. I am running stock with a trask turbo on my low rider and have over 10,000 miles. Mike you call your self a master tech but you fall for all the Gimmick aftermarket fixes

[@thomashall6937]

Stock head bolts breaking, wow that’s a problem. I would be pretty upset if that happened to my new bike. Does harley have a fix? Seems there have been other reports of head problems with the M8 motor. Great content guys. Thanks for the update

[@MoonshineHarley]

Anytime Thomas

[@jamielima5315]

Thomas Hall The head bolts are only breaking under larger performance builds.

[@PanM8]

Thomas Hall, did you watch the video? If you did, you didn't comprehend the information. These bolts break on PERFORMANCE, engine builds.

[@thomashall6937]

Thanks, i guess I misunderstood, so a Harley stage 4 with high compression pistons is not a performance build?

[@handyneighbour100]

Just bought ACV 0 1 17 2019 What is the best Cam to put in that someone told me Andrew 464 Or as a Harley p0wer cam better

[@NoName-vz1ob]

The Andrews cam will make more power. However it may not be the best choice if you are going to stick with the HD tuner.

[@PANTHEON71]

I don't have a problem with my head bolts breaking.. But then I own a Honda. Matter of facti haven't really had a problem with anything breaking on that. Almost 25 years old with over 100k on it and it still starts and drives everywhere I need it. Oil tires and gas... All it needs. I always want to go ride with my Harley buddies but their bikes are always "in the shop"

[@ihateemael]

a year or so down the track what have you learned? doing a followup?

[@MoonshineHarley]

We use S&S or ARP head bolts and haven’t had a single issue.

[@npw482]

Why use .030 cometic rather than .040 cometic?

[@Logan-or5qw]

Would you recommend an M8 owner To replace his gaskets with mls gaskets? Thanks. 😀👍

[@NoName-vz1ob]

Not just for fun. If you are doing performance modifications that include removing the heads then yes. I tend to veer towards the "if it isn't broke, don't fix it" approach to gaskets, springs, oil pumps etc.

[@Logan-or5qw]

@@NoName-vz1ob Yes sir, that answer makes a lot of sense. I plan on keeping the bike stock until the 2 yr. Warranty expires. Then consider putting slip on's. I was researching the Vance & Hines 40th anniversary slipons & from what they explained, you need to purchase a fuel 2 air mixture app. or Kit for it. Is this true? And if so, Would that require putting mls Gaskets on it? Thanks man. Your first response was really helpful to me. 👍

[@NoName-vz1ob]

@@Logan-or5qw The only reason you would need to replace the head gaskets is if you are going to bump up the displacement/compression from stock with a performance engine. And I don't recommend a FuelPak for a tuner. Power Vision is much more comprehensive and the price is not that different.

[@Johnclark300]

How long does a proformance engine last???

[@NoName-vz1ob]

They have the same lifespan as a regular engine. If you try to blow it up you will. If you try to make it last you will. Just like a stock one.

[@rhettkutney1935]

how bout a rushmore 103 build?

[@NoName-vz1ob]

There are some on the way...

[@kaboom362]

I thought with the angleometer, you had to complete the angle in one smooth steady motion as opposed to breaking it up in increments to reach the total

[@NoName-vz1ob]

No. It tracks the angle on the digital ones.

[@kaboom362]

@@NoName-vz1ob for experimental purpose. Clean and dry the head bolts. Make sure the holes dont have any fluids in them. then torque the head bolts to the first desired spec then the second spec if applicable then utilize the angleometer in one swift motion. Then measure the torque with a torque wrench. They should all be the same. Not so sure they would be if you turn it in increments. Especially if it is a torque to yield Bolt

[@NoName-vz1ob]

@@kaboom362 they are not installed dry. They should have a drop of oil on the threads and on the shoulder. We have checked them. I have a traditional anglemeter which is how I always did it until we started checking them. We have been working on this for 3-4 months now looking at the torque differences. And we never reuse the head bolts so that isn't a factor. The break away torque is consistent with our tightening readings. Fun stuff. Thank you for watching and getting involved. Love it.

[@kaboom362]

@@NoName-vz1ob gotcha. Thank you very much for the reply and the detailed explanation. Really enjoyed the video

[@NoName-vz1ob]

@@kaboom362 We appreciate your interest man. Keep the rubber down.

[@tommyarnold890]

The torque specs I've ever messed with are set once and you're done. What is the purpose of setting a torque value and then backing it off then resetting? Is it to generate heat through friction so the bolt and frame merge together?

[@NoName-vz1ob]

In this case it is to compress the gasket and then torque to spec. If you compress the gasket while applying the final torque it is possible to achieve a false compression level. This is the same reason it is recommended to put a drop off oil on the threads and head bolt faces to reduce friction while tightening.

[@tommyarnold890]

I see. Thank you.

[@garymoore3497]

It no longer matters. The HD motor company can not just lower prices. We now have access to Harley corporate balance sheets. This motor company in the red by almost 500 million. They are forced to sell bikes with substandard parts, just to generate the "shop-income" in some veil attempt to service some of these loans. This company in such a death spiral, is now only a matter of time before the banks start calling them in on some of these loans.........

[@christate1716]

........or they could build an engine with 6 head bolts instead of 4 then all of the torque on the bolts would be spread out more evenly...........but what do i know...........

[@robertpolkamp]

That would have made it another $10k for the bike..

[@frederickking1660]

Get a twin cam

[@fbj59]

I am so ticked off with Harley. I bought my first and last new Harley in 2018 Road Glide only 7K miles I get a loud knock in the engine. The HD tech tells me my rocker bolts have come loose, he said it caused damage to my pushrods and the cost to fix is around $2000.00. I knew Harley was junk before I bought it, but I figure if I buy new and properly service I might be ok. WRONG!!!

[@chrislion6777]

Too much heat generated by these power mods,a stylish radiator would eliminate these issues,,it's the only way to cool these high revving motors

[@eazyrider6122]

Barrels cracking, Head bolts breaking is there anything good about this bike i will never buy?!.

[@westcoast3595]

Question: since when did nuts become bolts? S&S knows cause they use science, mixed with common sense.

[@NoName-vz1ob]

Yes they are nuts. They are just refered to as bolts probably due to tradition.

[@oldninjarider]

"Metal doesn't squish" have you seen the Hydraulic Press Channel? #askingForAFriend

[@NoName-vz1ob]

Yes! It's almost therapy.

[@oldninjarider]

@@NoName-vz1ob I've even developed a Finglish dictionary. 😂 😂 😂

[@NoName-vz1ob]

@@oldninjarider 😂😂😂. I am going to use that and make you famous soon!

[@skorpius752]

This is one of the reasons you don't buy the newest thing. Harley is great at making bikes that need to be fixed before they work right. I'll let all the suckers deal with this over the next decade and then buy a cheap M8 powered bike and rebuild it so it actually works right.

[@frederickking1660]

Amen brother.

[@iwilrage]

Do you think other pro shops or harley shops know this info? Harley dealerships dont even let you talk to to the techs to ask them...I see so much info on your sight and want to go up there but your too far.. ow I just dont trust shops do things correctly

[@PrivateUsername]

I also hate broken ass-head bolts

[@grren1782]

okay so lowering the amount of torque you're putting on the cylinder is going to increase the speed of piston/cylinder wear unless your machine your own cylinders with that torque on torque plates You should know this

[@hardtailsuicidaljockey6827]

Harley topped out with late model evos 92-99 everything after that is garbage 🗑

[@arthurmchugh5184]

Funny, my 2001 Ducati had 197.000 miles on it and I NEVER touched the head bolts 😎😎🏍🍺

[@NoName-vz1ob]

These are high performance engines. Not stock.

[@arthurmchugh5184]

@@NoName-vz1ob you can't use high performance and Harley Davidson in the same sentence 😅😅🏍

[@Doucettedon]

Wouldn’t that indicate that your sealing surfaces are not flat? Or perhaps super flimsy that they can twist that much under torque. Either way sketchy as fuck.

[@charliewright4840]

Harley fails , S&S prevails.

[@nicholaskominski3746]

Or it could just be that factory harley hardware is absolutely fucking junk.

[@NoName-vz1ob]

There is nothing wrong with the factory hardware. We are adding bigger pistons/cylinders and increasing compression and valve lift over the factory design. I have never even heard of a stock M8 breaking a valve spring, head bolt, or blowing a head gasket. I'm sure someone on the internet will claim it's happening all the time (like the sumping issue which is also very rare in real life) but it simply isn't a thing.

[@nealamesbury1480]

What is wrong with harley ? Adam and eve rode harleys - and they still cannot make an engine..i love my bike,but consistent engine problems,really should put them outta business .

[@performancecyclespecialtie6104]

Pos

[@keithbaker3405]

The whole concept of those so called "Head bolt's" is of a flawed design. They are not bolts at all but rather sleeved nut's. The wall thickness between the bottom of the thread pitch and the outside diameter of the "Head bolt" is too thin. This being the case along with the fact that there is a sharp and acute angle occurring in the bottom of the thread is leading to high concentrated stress areas in the lower walls of those so called "Bolts"...this is really bad engineering practice. I am guessing the only reason HD has done this is so that you can do a top end overhaul in frame. It is a cheap and nasty solution and is a total bodge!

[@vector6977]

HD has been using this style since 1984. It happened back then, they changed the torque sequence. Nearly 30 years later, the problem comes back with the same solution.

[@BillyDaKid-pn2nn]

Did they fix this on 23 models