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

Patrick Harrison 👊🙌

@@MoonshineHarley any thoughts on my comment above?

Jim Manson we also never reused headbolts....

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!

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

@@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.

@@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.

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.

Yes. You can. S&S is a shitshow

@@grren1782 how so? Be exact.

@@vector6977 low tolerance horrible quality control shit show

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

That's fuckin funny

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.

@it'sallhappening absolutely.

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.

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

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.

We thought so too

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.

@@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 !

Anytime Thomas

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

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

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

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

Slew of problems?

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

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

🙏

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

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

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

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

No. It tracks the angle on the digital ones.

@@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

@@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.

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

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

Amen brother.

Clean and dry.

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.

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.

I see. Thank you.

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.

@@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. 👍

@@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.

There are some on the way...

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.

Yes! It's almost therapy.

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

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

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

These are high performance engines. Not stock.

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

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.

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.

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.