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Pretty sure I have a blown head gasket

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    Pretty sure I have a blown head gasket

    I’ve burped the the coolant system a few times. If I warm the bike up the fan kicks in about 1/2 way up the scale. When I go for a 30-50 mile run by the time I get home the gauge is above 50% 70% and climbing. I park at home and the fan is not kicking in. The overflow tank is burping antifreeze out the over flow.
    i pretty sure I’m blowing combustion gases into the cooling system. No water in the oil.
    what would be the recommended parts to order to change both head gaskets. The antifreeze under the bike was the reason the PO parked the bike 12 years ago.

    #2
    Bummer man. If you do a compression test, you might be able to narrow it down to one cylinder. Also, is there coolant in the oil? You’ll want to be 100% sure that it is a head gasket before you go to major surgery.

    IIRC, there isn’t much you need. Head gasket, maybe base gasket. The valve cover orings may be reusable. I would plan to replace the carb rubber boots. They are gonna be rock hard if they’ve never been replaced.
    Last edited by riot; 10-14-2022, 10:48 AM.

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      #3
      I had a similar problem with my Shadow 500. It was a bad (old) pressure cap. New pressure cap and all was well.

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        #4
        Pressure cap is possible. Cracked cylinder wall, head gasket also. Id do a compression test like riot recommended and a leak down test of it tests low at all.. You can get the tools at harbor freight for about $20 if you have a compressor.

        Head gasket is not that bad a job to do. You can do it with the motor in the bike.
        Don't spend money and buy, spend time and learn.

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          #5
          Not only can it be the cap... but it can be the housing that the cap seals to.

          If you were looking for a support group you're barking up the wrong tree. This place is fulla enablers dude. - Shooter77us

          The bitterness of low quality lingers long after the thrill of a low price has gone. - RacerX450

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            #7
            Originally Posted by rpcraft View Post
            There is a tester for head gasket leaks - Sure beats guessing.





            https://www.amazon.com/Block-Tester-...a-570352767565
            Exactly
            Get a cooling system pressure tester and perform the test and go forward with the results.
            I have seen so called technicians guessing at a fix and throwing parts at an issue wasting money and time.
            You can possibly rent/borrow a tester from one of the national auto parts stores.
            Acta non verba


            '88 Blue 99% stock SOLD
            '88 Restomod
            '22 Yamaha Tracer 9 GT

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              #8
              popping off the access cover and turning the crank manually through a few turns, you would likely notice any difference in compression resistance or sound.

              a blown gasket sometimes is visible on a sparkplug as a wet, greenish look.
              Last edited by squirrelman; 10-15-2022, 06:16 PM.
              "It's only getting worse."


              MY rides: '97 VFR750, '90 Red Hawk, '88 Blue/Black Hawk, '86 RWB VFR700 (3), '86 Yamaha Radian, '90 VTR250, '89 VTR250 (2), '73 CB125, '66 Yamaha YL-1

              Sold: '86 FJ1200, '92 ZX-7, '90 Radian, '73 CB750, '89 all-white Hawk, '88 blue Hawk, '86 FZ600, '86 Yam Fazer 700 , '89 VTR250, '87 VFR700F2, '86 VFR700F.

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                #9
                Originally Posted by Ziggy View Post

                Exactly
                Get a cooling system pressure tester and perform the test and go forward with the results.
                I have seen so called technicians guessing at a fix and throwing parts at an issue wasting money and time.
                You can possibly rent/borrow a tester from one of the national auto parts stores.
                There are cheaper versions with less fluid. The fluid is the costliest part of the kit I believe. I don't own one personally but if I run across a concern I will.
                88 Blue Hawk GT - Under construction but rideable (guest approved)
                89 BlackHawk 2.0 - On the lift and being assembled
                90 Hawk GT (color as to yet be determined) - Still on the shelf in crates

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                  #10
                  I’ll try a compression test. There is a kit for testing for hydrocarbons in the coolant , pricey though. I’ll look at the east things first

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                    #11
                    All a compression test really tells you is what the state of the sealing of the combustion chamber is so it could be rings, a burned valve, or yes, even a blown head gasket. A leak down test will help determine if you are leaking past the rings and the valves, and in some extreme cases it will leak down through a head gasket leak, but unless you have a complete blow out or a endo-scope there is no real indicator where you can see it.

                    Can you guess what helps determine if you have a gead gasket leak? You are using the wrong test for the wrong problem. Here is a pour in solution for 14 dollars that you can test in real time, you just have to use a little caution because it gts the bike coolant hot to check and then you have to look inside.

                    88 Blue Hawk GT - Under construction but rideable (guest approved)
                    89 BlackHawk 2.0 - On the lift and being assembled
                    90 Hawk GT (color as to yet be determined) - Still on the shelf in crates

                    Comment


                      #12
                      Originally Posted by rpcraft View Post
                      All a compression test really tells you is what the state of the sealing of the combustion chamber is so it could be rings, a burned valve, or yes, even a blown head gasket. A leak down test will help determine if you are leaking past the rings and the valves, and in some extreme cases it will leak down through a head gasket leak, but unless you have a complete blow out or a endo-scope there is no real indicator where you can see it.

                      Can you guess what helps determine if you have a gead gasket leak? You are using the wrong test for the wrong problem. Here is a pour in solution for 14 dollars that you can test in real time, you just have to use a little caution because it gts the bike coolant hot to check and then you have to look inside.

                      https://www.amazon.com/CS-Engine-Com...Q%3D%3D&sr=8-6
                      I ordered some of the comb tester.
                      I’ve had experience with head gasket leaking in the coolant before and this has all the same signs.

                      Comment


                        #13
                        A possibility.

                        I got a used Hawk pretty cheap and started fixing it up. Was blowing coolant out the overflow and running hot. Ran pretty good. No water in oil either. I started on the easiest cylinder (the rear one) removed the valve cover and checked the torque on the head bolts. One head bolt turned at under 25 pounds. It was stripped at the engine casing. I sold the bike for parts and told the buyer what the problem was. I think he planned to put a Heli coil in the case. Never heard back from him.
                        Bill,
                        88 Blue Hawk (bike #39), 89 Red Hawk, 2021 Rebel 1100 (bike 41) Some Past/sold in reverse order:,FZ09,97 Magna #1&2 , 97 VFR750F, 87 VFR400R, 88 Hawk, 86 SRX 600, 77 RD400, 79 CB650, 04 VFR, 88 Blue Hawk, 89 Red Hawk, Yamaha SRX600, Harley 1200C, Yamaha RD400, Harley 883R, Yamaha 750 triple, Vlx600, Honda 450, Honda 400, CB550F, Kawasaki H1, BMW R69US, Yamaha R5C 350, Honda 160, Bridgestone 175, 1950 Harley 74 w/sidecar, 65 Harley 250 Sprint, 1948 Harley and my 1st bike-1941 Harley 74 knucklehead my dad gave in1963.

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                          #14
                          Originally Posted by BillnOroville View Post
                          A possibility.

                          I got a used Hawk pretty cheap and started fixing it up. Was blowing coolant out the overflow and running hot. Ran pretty good. No water in oil either. I started on the easiest cylinder (the rear one) removed the valve cover and checked the torque on the head bolts. One head bolt turned at under 25 pounds. It was stripped at the engine casing. I sold the bike for parts and told the buyer what the problem was. I think he planned to put a Heli coil in the case. Never heard back from him.
                          I will check the torque when I take it apart. I think I read on here one person found the head bolts loose and was able to torque them up and solve his problem. Either way I plan on fixing the bike

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                            #15
                            The rear/left stud on the rear cylinder tends to pull out of the case. Have seen it a handful of times. Tried a heli-coil once and it didn't work. Something better like a time-sert might?

                            It's not common for a Hawk to blow a head gasket, but it does happen. Usually because of something else. (overheating, detonation from poor fuel, too much advance, etc) It's more common for it to be a rad cap/thermo housing problem, which is the easiest thing to check. (and the housing probably needs a full rebuild anyway, o-rings, cap, thermo) Compression test won't tell you anything on a head gasket leak. If it was leaking that bad, you'd hear it.

                            Originally Posted by BillnOroville View Post
                            A possibility.

                            I got a used Hawk pretty cheap and started fixing it up. Was blowing coolant out the overflow and running hot. Ran pretty good. No water in oil either. I started on the easiest cylinder (the rear one) removed the valve cover and checked the torque on the head bolts. One head bolt turned at under 25 pounds. It was stripped at the engine casing. I sold the bike for parts and told the buyer what the problem was. I think he planned to put a Heli coil in the case. Never heard back from him.
                            J.D. Hord
                            Keeper of Engine Nomenclature, 9th Order

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