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I think I did it now... I have two engines and no head.

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    #1

    I think I did it now... I have two engines and no head.

    Well, the bolt extraction from my 750 head went rediculously bad. First, I tried an "easy out" tapered extractor. After drilling a few pilot holes and breaking 3 drill bits it was clear the extractor wasn't gonna work at all. Next attempt involved a left hand drill bit. First attempt it drilled down and just kept drilling a hole in the center of the broken bolt. Ok, that's not gonna work, speed it up and move on to the next flush mounted bolt. Push the press down, turning 1000 RPM. It begins to drill a pilot hole and before it gets far SNAP! $4.50 "hardened" bit gone. Now I'm a little lost. Where can I find Helicoils that will fit? I think the only way I'm going to win is to helicoil it. By the way, the broken bolts hold down the cam bearing caps in a 78GS750. ANY IDEAS? The other head is a gs1000 head with a junk exhaust valve.
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    #2
    Helicoils can be tough to do right. These look to be a better solution. http://www.chicagoclassicimports.com/timesert.htm

    Comment

      #3
      Originally posted by Billy Ricks
      Helicoils can be tough to do right. These look to be a better solution. http://www.chicagoclassicimports.com/timesert.htm
      That looks great, do you know what size bolts the cam caps are? I'm pretty sure they are 6mm...

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        #4
        On a GSthou they are definitely M6.
        Helicoils are OK as long as you are doing them carefully - but the installation kit costs an arm & a leg! If you try to shortcut the installation that is when you get problems.

        Comment

          #5
          Originally posted by Paul
          On a GSthou they are definitely M6.
          Helicoils are OK as long as you are doing them carefully - but the installation kit costs an arm & a leg! If you try to shortcut the installation that is when you get problems.
          I know they are the same between the thou and the 750, so there's my answer... now to call timesert...

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            #6
            That timesert sure does look good... too bad the number on the website is for a company that no longer carries them.... the search continues.

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              #7
              Yeah those inserts look good, but don't write off the good old heli-coils, I managed to bust 6 of my 8 exhaust bolts on my GS1000S after electrolysis (no, nothing to do with hair removal) had chemically "welded" the original plain steel bolts into the alloy casting.

              To remove the remains, I did the tiny drill bit, then next size up, then next size up etc etc, until I had removed the remains of the old bolts (and, sadly the internal thread) and inserted heli-coils. I've had my new pipe on and off several times since with no problems, but of course I'm using stainless bolts now.

              "Easy outs" would have to be the greatest misnomer in engineering history, I don't think I've ever seen one work, and they are a buggar to get out when they snap as they are so bloody hard. I've just finished removing the remains of someone else's folly when they tried to remove a broken inlet manifold screw, then busted off any easy out, so just left it and put the bike back together.

              It took a die grinder to remove and I'll have to fill the crater with "Devcon" then helicoil it before I can use it. Ah well, it fills my days, ha ha! :twisted:

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                #8
                I think I did it now... I have two engines and no head.

                Hey, I found Timesert at www.timesert.com
                They look like a cool item to me.
                Jack

                Comment

                  #9
                  Hey guys, whats your problem with Helicoils? They are so easy to do, just drill out the damaged hole with the correct size drill, re-tap with supplied tap and wind in the thread insert. Easy! Easier than timeserts (I've used both)

                  Helicoils were the preferred method of thread repair and strengthening when I was trained as an aircraft engineer, and are used by many companies to strengthen threads in light alloys.

                  I helicoil all my cam cap threads before reassembling a head as its much easier to keep clean, and you can be sure at least one thread will fail when fitting the cams; when doing one with the head in situ I use a vacuum cleaner while drilling to remove swarf.

                  Easi-outs on the other hand do require some skill to use, but don't write them off. Firstly buy good quality ones, not Chinese. Then use them only in the right situation. If your screw broke off because its seized in place, then an easi-out won't get it out either, except with great care, lots of penetrating oil and heat. Even then....
                  However if your screw breaks in a clean thread as you tighten it up then thats what easi-outs were designed for.

                  Keep on pluggin away Ben

                  Comment

                    #10
                    Well, you won't beleive the way two of the bolts broke off... I had loosened (not yet removed, loosen first, then back all the way out is the way I was taught) all the bolts on one cam cap, and had started loosening the bolts on the other cap. After loosening two, as I moved to loosen the other two there was a SNAP and the cap came off nice n easy... so basically the bolts had had all the abuse they could handle, as I hadn't replaced them yet, so they were probably stock 78 bolts. I guess the heat and pressure cycles got to themand they became too fragile to hold a verticle pressure. I'm thinking helicoil after checking a few sites with timeserts... I can't afford 70+ dollars for 5 inserts... c'mon, I can get an assortment of heli kits from ebay for 30 dollars. I'm kinda hesitant about spending much more money on this 750 engine, as I really wanna do-up the 1000. Right now the plans are to port and polish, degree the cams, with lumpier cams, **maybe** a big bore kit and 29mm smoothbores, if money allows. Polishing the clutch, stator, timing, cam cover and possibly just polishing the whole thing. another color scheme would be to polish the covers, paint the engine flatblack and clearcoating over the polished covers with a smoke clearcoat. I'm also still awaiting word on whether or not the school is going to allow me to build a "sleeper" blower for the 1000 as a UROP. The professor I talked to got pretty excited about it, but the dean was a little more hesitant. I'm also going to submit another UROP to convert the 1000 to "hidden" fuel-injection, by gutting the carbs and installing fuel injectors in that, than developing custom fuel maps. I don't think they will allow me to do both, but maybe if I develop all the drawings on my own I can use the equipment in the school to cut and assemble it.

                    Comment

                      #11
                      The TEC II fuel injection computer works well and its manual is available for download on the internet. You ought to check it out but it is expensive. There are also groups of people on the internet who are developing free schematics for injection systems.

                      Steve

                      Comment

                        #12
                        That's still a ways off yet... I have to come up with 600 dollars in 3 weeks so I can visit my fiance in spain, before she comes back... after that I have to start saving for the wedding... my parents don't exactly support the idea of the wedding, so it looks like full cost is on me, her and her parents... I will definately check it out though, if it's expensive, I'll get my comp engineering major buddy to do a UROP on one, afterall, we do get paid for UROPs

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