Page 1 of 2
GT750 Broken head bolts
Posted: Mon Jan 12, 2015 8:59 am
by JSJamboree
Ive spent the last hour or so searching for assistance with this issue, but no one seems to have this issue. In fact I have read many posts where people stated they have never had this issue once, let alone 6 times.
Every small head bolt broke off in my jug. Now, two of them broke off above the jug, 1 broke off below the jug (PO) and the rest broke off at the jug. One of them that broke off above the head I was able to extract by grabbing on with a pair of vice grips and rocking back and forth until it became loose. The second one I tried broke off at the jug. So, it does seem the issue here is corrosion in the threads. I had to use a shim system to get the head off, so the jugs are going to require a puller. My issue there is I cant secure a puller since all the bolts are broken off.
I dont want to use an easy out, because there is a 100% chance it'll break off in one of them then I couldn't even get a machine shop to drill them out.
Black = slightly above the jug, but not enough for vice grips
Blue = Broken at the jug, pretty much flush
Red = Broken below the jug
Green = clear
Anyone have any advice?
Re: GT750 Broken head bolts
Posted: Mon Jan 12, 2015 3:39 pm
by Suzukidave
It sure would help to be able to put the block right on a mill table or drill press so the remaining studs could be carefully milled or drilled out . Being you are going to need a puller plate to get the block off the cases and not having the small bolts available to hold the plate down will be a problem .What you could do but will take more work to make the puller is put together a puller plate that uses the intake and exhaust ports to hold the plate down . It would look close to the normal puller plate with the push down bolts above every stud hole but instead of the normal holes drilled for the hold down bolts .. 6 ~ [ shaped steel brackets will have to be cut out that will fit over the top of the puller plate and also slip into the openings for the intakes and exhaust . I have seem one of these used by another list member and he said the design worked very well . All the parts cut out of 1/2" steel should do the job .
Re: GT750 Broken head bolts
Posted: Mon Jan 12, 2015 4:15 pm
by JSJamboree
Suzukidave wrote:It sure would help to be able to put the block right on a mill table or drill press so the remaining studs could be carefully milled or drilled out . Being you are going to need a puller plate to get the block off the cases and not having the small bolts available to hold the plate down will be a problem .What you could do but will take more work to make the puller is put together a puller plate that uses the intake and exhaust ports to hold the plate down . It would look close to the normal puller plate with the push down bolts above every stud hole but instead of the normal holes drilled for the hold down bolts .. 6 ~ [ shaped steel brackets will have to be cut out that will fit over the top of the puller plate and also slip into the openings for the intakes and exhaust . I have seem one of these used by another list member and he said the design worked very well . All the parts cut out of 1/2" steel should do the job .
Do you remember if the top L was fastened the plate at all or did it just rest on top? I would have concern that it would bend/snap the intake runners since they stick out so far.
Re: GT750 Broken head bolts
Posted: Mon Jan 12, 2015 4:44 pm
by Suzukidave
The device was described but i dont remember seeing a picture , designing a way for the top of each [ to attach to the top plate to keep them from slipping off would seem to be a great idea . Having the lower part of the [ extend as far as possible into the intake and exhaust port also would seem to be a great idea to place the pressure of the pull on the "meat" of the block . Thinking about it i suppose on the intake side the bracket could be made to fit over the intake stub .. again more work but maybe stronger ?
Re: GT750 Broken head bolts
Posted: Mon Jan 12, 2015 5:33 pm
by Cliff
Have you tried to remove the cylinders yet? Don't forget to remove the short bolt at the back under the intake for the right cylinder!
IF you can get the cylinders off the cases, you can try to weld nuts to the broken studs, let it cool and see if they will come out. Or take it to a machine shop.
Re: GT750 Broken head bolts
Posted: Mon Jan 12, 2015 5:51 pm
by Desert_75
I saw your post over on DTT, hopefully you get them out soon. In the meantime...
http://www.ebay.com/itm/1974-1975-SUZUK ... 1241976564" onclick="window.open(this.href);return false;
Re: GT750 Broken head bolts
Posted: Mon Jan 12, 2015 10:59 pm
by JSJamboree
Was laying here in bed and I was thinking. Instead of [ brackets... Why not just use C clamps.. This would ensure everything is tight and sturdy..I need to get some 1/2" plate, then it's on to testing.
Also yes, I have tried to get it off already. Took off the nut, and then beat on it with a rubber hammer under the exhaust outlets as described in my manual. Not even the slightest of budge. Instead of breaking the water jacket, just going to work on the plate idea.
I'm really hoping that I get it off and am able to get it all fixed up after that. The cylinders look really good, head domes looked good, Pistons looked good. just a bunch of broken bolts.
Re: GT750 Broken head bolts
Posted: Tue Jan 13, 2015 7:19 pm
by aslsmm
Removing these cylinders has cause more head ache for me than any other bike. Having said that there is a way on the kawasaki triple forums that might work. You need to thread all the large bolt holes, then you need these
Re: GT750 Broken head bolts
Posted: Tue Jan 13, 2015 10:56 pm
by Suzukidave
I also made up a set of the puller bolts years ago but found out the the cast in stud holes are not all the same , some are cast in just a bit larger so they may thread for the big bolt but the threads will not be deep enough to hold the pressure . All of a sudden the threads will start to pull out of the block . Seems these blocks get extra stuck and the puller plates are the way to go to get them off .
Re: GT750 Broken head bolts
Posted: Wed Jan 14, 2015 3:52 pm
by old racer
Cliff wrote:Have you tried to remove the cylinders yet? Don't forget to remove the short bolt at the back under the intake for the right cylinder!
IF you can get the cylinders off the cases, you can try to weld nuts to the broken studs, let it cool and see if they will come out. Or take it to a machine shop.
I have used this method many times with great success,But i have never tried it on the 750 cyl.
But it's still just a snapped stud, so if it were me i would weld nuts on the remains of the stud.
Re: GT750 Broken head bolts
Posted: Wed Jan 14, 2015 8:28 pm
by JSJamboree
old racer wrote:Cliff wrote:Have you tried to remove the cylinders yet? Don't forget to remove the short bolt at the back under the intake for the right cylinder!
IF you can get the cylinders off the cases, you can try to weld nuts to the broken studs, let it cool and see if they will come out. Or take it to a machine shop.
I have used this method many times with great success,But i have never tried it on the 750 cyl.
But it's still just a snapped stud, so if it were me i would weld nuts on the remains of the stud.
Yeah, Tried it on one. I put down a washer with a nut on top, welded it solid.. The weld just snapped.
Re: GT750 Broken head bolts
Posted: Wed Jan 14, 2015 8:36 pm
by JSJamboree
JSJamboree wrote:old racer wrote:Cliff wrote:Have you tried to remove the cylinders yet? Don't forget to remove the short bolt at the back under the intake for the right cylinder!
IF you can get the cylinders off the cases, you can try to weld nuts to the broken studs, let it cool and see if they will come out. Or take it to a machine shop.
I have used this method many times with great success,But i have never tried it on the 750 cyl.
But it's still just a snapped stud, so if it were me i would weld nuts on the remains of the stud.
Yeah, Tried it on one. I put down a washer with a nut on top, welded it solid.. The weld just snapped. At this point im working on getting a puller plate with C clamp setup to try that first. Hopefully I'll get the cylinders off, then I can just drill out the bolts.
Re: GT750 Broken head bolts
Posted: Sat Jan 17, 2015 10:25 pm
by JSJamboree
well today didn't go so well with the Jugs. I got a plate made (out of 3/8 not quite 1/2). And I used C clamps to hold it to the head. The first attempt 3 of my 6 c-clamps broke from the stress. They werent the best quality but I still didn't expect that.
Went out and bought some new clamps and not much better. The clamps just cant hold it to the top so the sides are bending. Around the 1 c-clamp thats big and old, I actually shattered the threads on the bolt (with a really loud pop) because there was soo much pressure on them. My impact cant drive any of the bolts down farther and they are starting to bend themselves from the torque ( they are grade 5). I then tried to hammer a thin wedge between the cylinder and the case as a last resort, I couldn't get anything to budge even with that. At this point im not sure there is much more I can do. Honestly if it was bolted to the head, I dont see how the threads would hold in the allum.
Any last resort ***** up the jugs but save the case method? It'll be cheaper to source a jug than a full motor in shipping alone.
Re: GT750 Broken head bolts
Posted: Sun Jan 18, 2015 3:48 am
by Suzukidave
Yep .. it looks stuck all right but i have seen plenty just this bad . Stick with it ...oil down the stud holes and heat around the base of the block with a propane torch to get the metal expanding ... gotta break that bond . Its something how this process will bend 3/8" steel . Trying to get a wedge between the block and the case isnt a good idea , if you mess up the sealing surface of the top case it would be bad .
Re: GT750 Broken head bolts
Posted: Sun Jan 18, 2015 8:13 am
by titan performance
You could probably make a simple jig device in order to guide a hand drill into the broken studs, and repair them with coils, leaving the jug where it is. But looking at the forces it has already resisted, I don't think I would then trust the repaired threads to lift the jug. I would say that something has to give using the method you are, ie the ports....you just need to beef up the tools to take the strain. As one of the other guys said, don't try putting tools between the case and the jug. I've not had this issue with a 750, but have suffered similar with 500 barrels, sorry, jugs, rusted to the studs. After using all of the penetrating fluids, and the jugs still not pulling off....I freed them eventually with persistent shock treatment. It's hard to find somewhere to hit it upwards, but with the puller under tension and repeated beatings with a very heavy rubber mallet, and a club hammer with blocks of wood, I eventually shifted it....little by little.
