Results 1 to 9 of 9
  1. #1
    Member
    Join Date
    Feb 2015
    City
    Kansas City
    State
    Kansas
    Posts
    71

    I think I have a blown head gasket on my M8

    I'm right at about 4300 miles on my 2018 SGS and it appears that I might have a blown head gasket. What drew my attention to a possible problem was the way the bike acted when I went to start it up after it sat for about a month and a half. It idled high (3500 rpm) for about 6 seconds and then dropped down to a normal idle. I took it out for a short ride and it sounded like it has an exhaust leak. The bike sat for a couple of weeks and when I started it up, it idled high again for about 3 seconds and died. I began looking around the front and rear heads with an LED light and noticed that there is carbon on the edge of the head gasket in the front center. Damn! I'm aware that some M8s have encountered blown head gaskets, but I was hoping I wouldn't become one of them. The pic is sideways for some crazy reason, but you can see the carbon that I am speaking of. The rest of the gasket edges (front and rear cylinders) are rust colored.
    Attached Images Attached Images
    Last edited by NGOT8R; 11-29-2019 at 02:43 PM.


    2015 Vivid Black SGS w/107 motor: V&H Pro Pipe, Thundermax tuner, SE Ventilator Elite AC with K&N filter, Andrews 30T pulley mod, AIM variable pressure clutch, Evolution Industries billet clutch basket, Twin Power compensator eliminator sprocket, HD highway pegs, HD passenger floorboards, RB Racing modified stock swingarm (2" over adjustable), HD 7" Wind Splitter windshield, HD black windshield trim, JM Corp 250W 2 channel amp and Focal 165 KRC speakers in fairing

  2. #2
    Administrator hulkss's Avatar
    Join Date
    Sep 2013
    City
    Luck
    State
    Wisconsin
    Posts
    487
    Maybe an intake manifold leak? That can cause erratic idle and poor running. The stock plastic manifolds have had issues.
    2014 FLHXS: Sand Camo Denim
    H-D Parts Except as Noted: updated 07-Jan-2019
    Front Lighting: Illuminated Hand Control Switches; Auxiliary Lamp Kit; Norman 3000K LED Lamps W/PAR 36 Amber Lens Covers; JW Speaker Evolution II LED Headlight; Amber LED Turn Signals
    Rear Lighting: LED Light Bar; Tri-Bar Fender Brake Light; Tour-Pak and Saddlebag Run/Brake/Turn LED Lamps
    Chrome: Fork Sliders & Covers; Axle Spacer; Fairing Skirt; Curved License Frame; Classic Timer Cover; Docking Point Covers; Windshield Trim; Rear Saddlebag Guards; Radio Trim; Stealth Tour-Pak Rack; Tour-Pak Lamp Trim; Smooth Horn Cover; Saddlebag Hinge Covers; Landmark Fat Round Shift Linkage; Klock Werks Flush Front Axle; Inner Primary Housing; Solenoid Cover; Chopped Engine Guard; Front Engine Mount & Link; Arlen Ness Smooth A/C Cover; Oil Cooler Protection Screen; Kuryakyn Fender Accents and Trim
    Security: Smart Siren II; Brukus TourPack Bullet Secure; Reda Saddlebag Locks; FOBO Tire Pressure Monitors; V-Twin Metal Valve Stems; Micro Start Kit W/Harness & Tire Inflator; Fuel Door Lock; Abus 7000 Disc Lock Alarm
    Engine: 103"; Line2Line Coated Stock Pistons; Andrews 57H cam; S&S Premium Tappets; CNC Ported Heads; SE Wide Band Auto-Tuning Module; SE Pro Super Tuner; SE High Flow Street Cannon Exhaust; SE A&S Clutch Kit; Rekluse Centrifugal Clutch Pack; Dipstick Temp Gauge; S&S Stealth Air Cleaner; Yuasa GYZ Battery, 1.4 kW Starter; Amsoil; Mighty Might Cooling Fans & Accy Switch; GMR Compensaver; Pingel Shifter Shaft; High Output Charging System; SE Spark Plugs & Wires
    Handling: Cartridge Fork Dampening; Amsoil Suspension Oil; 18" Front Wheel; Floating Brake Rotors; EBC HH Brake Pads; Dunlop American Elite Tires; Ohlins HD 773 Shocks
    Comfort: Police Solo Saddle with Coil-Over Suspension; Extended Reach Footboards; SoftBrake 1 Extended Brake Lever & Reduced Reach Clutch Lever; Extended Shift Levers; Fairing Air Deflectors; Freedom 14" Windshield; Klock Werks Ergo Up Bars; Get-A-Grip Hand Grips; Kuryakyn Magnum Plus Mirrors
    Infotainment: Ultra Tank Console with Headset Connection & CVO Insert; Hidden Radio Antenna; GPS Map Update
    Luggage: Four Point Docking Hardware; Solo Tour-Pak Mounting Rack; King Tour-Pak and Lining; Tour-Pak Wall Organizer; Premium King Travel-Pak; Chopped Backrest Pad; Premium Saddlebag Travel-Paks; Innovative Storage Solutions Tool Bags; Saddle Bag Guard Bags & Bottle Holders
    Appearance: CVO Black Gauges; Carbon Fiber Gauge Panel; De-badged Gas Tank; Skull Emblems over Fairing Mirror Holes; Diamond Engineering 12 Point Engine Screws; Allen Hole Plugs; Piston Muffler End Caps

  3. #3
    Member
    Join Date
    Feb 2015
    City
    Kansas City
    State
    Kansas
    Posts
    71
    Thanks Hulk. I'll take a look at the intake as well. What are your thoughts on the black soot that appears to be carbon on the edge of the front head gasket? This problem is so weird, in that it just popped up all of a sudden. I'm going to investigate things more thoroughly once I finish up with my Sportster build.


    2015 Vivid Black SGS w/107 motor: V&H Pro Pipe, Thundermax tuner, SE Ventilator Elite AC with K&N filter, Andrews 30T pulley mod, AIM variable pressure clutch, Evolution Industries billet clutch basket, Twin Power compensator eliminator sprocket, HD highway pegs, HD passenger floorboards, RB Racing modified stock swingarm (2" over adjustable), HD 7" Wind Splitter windshield, HD black windshield trim, JM Corp 250W 2 channel amp and Focal 165 KRC speakers in fairing

  4. #4
    Administrator hulkss's Avatar
    Join Date
    Sep 2013
    City
    Luck
    State
    Wisconsin
    Posts
    487
    I guess you could do a cranking compression check or a cylinder leakdown test.
    2014 FLHXS: Sand Camo Denim
    H-D Parts Except as Noted: updated 07-Jan-2019
    Front Lighting: Illuminated Hand Control Switches; Auxiliary Lamp Kit; Norman 3000K LED Lamps W/PAR 36 Amber Lens Covers; JW Speaker Evolution II LED Headlight; Amber LED Turn Signals
    Rear Lighting: LED Light Bar; Tri-Bar Fender Brake Light; Tour-Pak and Saddlebag Run/Brake/Turn LED Lamps
    Chrome: Fork Sliders & Covers; Axle Spacer; Fairing Skirt; Curved License Frame; Classic Timer Cover; Docking Point Covers; Windshield Trim; Rear Saddlebag Guards; Radio Trim; Stealth Tour-Pak Rack; Tour-Pak Lamp Trim; Smooth Horn Cover; Saddlebag Hinge Covers; Landmark Fat Round Shift Linkage; Klock Werks Flush Front Axle; Inner Primary Housing; Solenoid Cover; Chopped Engine Guard; Front Engine Mount & Link; Arlen Ness Smooth A/C Cover; Oil Cooler Protection Screen; Kuryakyn Fender Accents and Trim
    Security: Smart Siren II; Brukus TourPack Bullet Secure; Reda Saddlebag Locks; FOBO Tire Pressure Monitors; V-Twin Metal Valve Stems; Micro Start Kit W/Harness & Tire Inflator; Fuel Door Lock; Abus 7000 Disc Lock Alarm
    Engine: 103"; Line2Line Coated Stock Pistons; Andrews 57H cam; S&S Premium Tappets; CNC Ported Heads; SE Wide Band Auto-Tuning Module; SE Pro Super Tuner; SE High Flow Street Cannon Exhaust; SE A&S Clutch Kit; Rekluse Centrifugal Clutch Pack; Dipstick Temp Gauge; S&S Stealth Air Cleaner; Yuasa GYZ Battery, 1.4 kW Starter; Amsoil; Mighty Might Cooling Fans & Accy Switch; GMR Compensaver; Pingel Shifter Shaft; High Output Charging System; SE Spark Plugs & Wires
    Handling: Cartridge Fork Dampening; Amsoil Suspension Oil; 18" Front Wheel; Floating Brake Rotors; EBC HH Brake Pads; Dunlop American Elite Tires; Ohlins HD 773 Shocks
    Comfort: Police Solo Saddle with Coil-Over Suspension; Extended Reach Footboards; SoftBrake 1 Extended Brake Lever & Reduced Reach Clutch Lever; Extended Shift Levers; Fairing Air Deflectors; Freedom 14" Windshield; Klock Werks Ergo Up Bars; Get-A-Grip Hand Grips; Kuryakyn Magnum Plus Mirrors
    Infotainment: Ultra Tank Console with Headset Connection & CVO Insert; Hidden Radio Antenna; GPS Map Update
    Luggage: Four Point Docking Hardware; Solo Tour-Pak Mounting Rack; King Tour-Pak and Lining; Tour-Pak Wall Organizer; Premium King Travel-Pak; Chopped Backrest Pad; Premium Saddlebag Travel-Paks; Innovative Storage Solutions Tool Bags; Saddle Bag Guard Bags & Bottle Holders
    Appearance: CVO Black Gauges; Carbon Fiber Gauge Panel; De-badged Gas Tank; Skull Emblems over Fairing Mirror Holes; Diamond Engineering 12 Point Engine Screws; Allen Hole Plugs; Piston Muffler End Caps

  5. #5
    Member
    Join Date
    Feb 2015
    City
    Kansas City
    State
    Kansas
    Posts
    71
    Quote Originally Posted by hulkss View Post
    I guess you could do a cranking compression check or a cylinder leakdown test.
    I do plan to perform a leakdown test, just as soon as I can pick up a tester.


    2015 Vivid Black SGS w/107 motor: V&H Pro Pipe, Thundermax tuner, SE Ventilator Elite AC with K&N filter, Andrews 30T pulley mod, AIM variable pressure clutch, Evolution Industries billet clutch basket, Twin Power compensator eliminator sprocket, HD highway pegs, HD passenger floorboards, RB Racing modified stock swingarm (2" over adjustable), HD 7" Wind Splitter windshield, HD black windshield trim, JM Corp 250W 2 channel amp and Focal 165 KRC speakers in fairing

  6. #6
    Administrator Mojo's Avatar
    Join Date
    Dec 2013
    City
    Nashville,
    State
    Tennessee
    Posts
    6,709
    I have a friend that just had rear head gasket blown/ 2017 FLHXS - 24,000 miles. Out of warranty, Dealer fixed it no charge.
    2018 FLHXANV
    Milwaukee Eight 107 l Reinhart Slip Ons l 4 Point detach l Low Backrest l ClearView Shield l Fairing wings l Fork deflectors
    Custom Dynamic Fr & Rr LED's l Halo headlight l CVO seat l 115 Anniversary Razor Tour Pak
    .

  7. #7
    Member
    Join Date
    Feb 2015
    City
    Kansas City
    State
    Kansas
    Posts
    71
    Quote Originally Posted by Mojo View Post
    I have a friend that just had rear head gasket blown/ 2017 FLHXS - 24,000 miles. Out of warranty, Dealer fixed it no charge.
    I'm probably on my own if the head gasket is blown Mojo. I installed an S&S cam and tuner a year ago.


    2015 Vivid Black SGS w/107 motor: V&H Pro Pipe, Thundermax tuner, SE Ventilator Elite AC with K&N filter, Andrews 30T pulley mod, AIM variable pressure clutch, Evolution Industries billet clutch basket, Twin Power compensator eliminator sprocket, HD highway pegs, HD passenger floorboards, RB Racing modified stock swingarm (2" over adjustable), HD 7" Wind Splitter windshield, HD black windshield trim, JM Corp 250W 2 channel amp and Focal 165 KRC speakers in fairing

  8. #8
    Prospect
    Join Date
    Dec 2014
    City
    San Diego
    State
    California
    Posts
    10
    I had an Evo motor on a chopper that used to blow head gaskets every year or so. You should be able to hear it and feel it - you'll hear the "pfft pfft pfft" of compression leaking and feel the blow by at the leak.
    2015 Street Glide Special - Vivid Black

    Go Fast:
    Rush Big Louie slip ons | Vance & Hines Naked air filter | FP3 (Stage 1 map)
    Look Good:
    White trash hidden antenna mod
    Custom Dynamics Dynamic Ringz (front) | Custom Dynamics LED turn signals (rear) | XenonDepot H11 upgrade
    Be Comfy:
    Long Ride Shields 7" Ultra
    Detachable passenger backrest | Detachable luggage rack
    ARC Audio Moto 600.4 amp | ARC Audio Moto 602V2 speakers
    JNR Designed Rear Air Ride | Fast up tank | Ride Height Repeater

  9. #9
    Founding Member TomA's Avatar
    Join Date
    Apr 2014
    City
    Battle Mountain
    State
    Nevada
    Posts
    1,705
    Quote Originally Posted by NGOT8R View Post
    I'm probably on my own if the head gasket is blown Mojo. I installed an S&S cam and tuner a year ago.
    Sound's like your up for another build of course if your taking the head off why not have them worked on just a little bit. You have t replace the second one just for peace of mind right. That Zipper's kit Michael had installed looked like fun.


    2014 Mysterious Red Sunglo
    Stage 1 D&D Boss Fat Cat 2-1 exhaust FP3 tuner
    JW Speaker E2, Custom Dynamic running and tails, 8 plasma rods
    Soundz Customz level 5 Carbon Iron series, 5x7 lids
    Color matched inner fairing and King tour pack with lowers
    Fork fangs, Fairing deflectors, REDA bag bolts

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •