Cylinder bolt removal??

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#1
Hi i recently rebuilt my cr250 , unfortunately the torque wrench was not reading correctly and i snapped off a cylinder head bolt when putting the cylinder head on. My question is how do i remove the nut?, and preferably without having to remove the cylinder again. ( The nut has about 2cm left in the cylinder)..
HAPPY NEW YEAR!!!!!!!!!!!!!!!
 

muddy226

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#2
If you mean that the stud has snapped off just below where the head nut normally seats I'm afraid you will have to remove the head again, and then remove the remainder of the stud from the cylinder and replace it with a new one. If you know of anyone with a stud remover that would be best, otherwise the trusty vice grips or stillsons will come into play. I hope I have understood your question correctly.
 
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#3
Yes thats where i mean, its just the stud has snapped off a bit lower down, so i cant get a needle nose pliers in to get it out. Would a smaller length stud go straight in, without problems?
 

Rich Rohrich

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#4
Originally posted by blanc
Would a smaller length stud go straight in, without problems?
Unfortunately no, that won't work. You need to remove all of the broken stud and replace it with a new stud of the stock length. For a given diameter of stud there is a minimum number of threads that need to be engaged for the stud to hold. If you reduce the number of threads with a shorter stud it will likely fail while the engine is running causing the head gasket to leak and possibly warping the head.

It's worth the effort to do a proper fix. :thumb:
 

storytime

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#6
What all the outhers have missed is the fact that HONDA USES A TAPERED STUD! The stud has a flange that helps it seat into the cylender. The head removel is a must as the flange will not be able to get through the hole in the head. If you do unthread the stud you will mostlikly warp the head if too much force is applied from the underside due to the flange. Take the head off
buy a new stud and gasket and do the job right the first time.
 
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#7
[I am still unable to remove the stud , will i have to drill and then tap the cylinder again? If so how exactly do you do that?
:|
 

storytime

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#8
Stud?

blanc said:
[I am still unable to remove the stud , will i have to drill and then tap the cylinder again? If so how exactly do you do that?
:|
:flame: OK, don't sweat it ! If the head is still on you need to remove it. If the stud still has the nut on it and this makes removing
the head impossable try this. If the threds on the stud are buggered up cut off the stud as short as possable, then remove the nut, or you can try splitting the nut not too tough of a job just be patient, go slow and keep nipping away at it.
If the stud still has the nut on it , BUT THE NUT IS LOOSE!
this will allow you to cut the stud below the nut then remove the head.
Now that the nut is off and this allows the head to be removed you are looking at the top of the piston and the cylinder. Put the piston up to the top of the cylinder and this will keep any debres from falling into the ports and into the lower end. Cover the top of the piston and as much of the cylinder as possable to safe guard all but the area of the cylinder that has the bad stud. From the factory the cylinder had LOCKTITE applied to the threds of the stud before it was screwed into the cylinder the only way to release the grip of the locktite is heat. So now you need the use of a good propane torch , be sure the coolent has been drained prior to the heating of the cylinder. Heat the cylinder from the outside
first then from arround the water jacket trying to concentrate the heat into the cylinder just arround the stud boss. Use of a damp rag arround area you do not want to over heat is also a good idea. With patience and any luck a set of visegrips
will remove the stud. The key to heating the stud area of the cylinder is to look for the locktite to bubble up from the threds
of the stud, this will take quite a bit of heating so be patient.
Once the locktite is bubbling ,spray just a little WD-40 or any type of penetrating oil, be careful as this may want to flame up, use a wet rag to controll the flame up, now that the bubbiling is occuring grab your visegrips and unscrew that mean old nasty stud. Clean cylinder with contact cleaner
( after it has cooled down) to get rid of as much old locktite.
If you have the correct tap chase the threds in the cylinder
blow out with compressed air and apply RED locktite to the threds of the stud to be screwed into the cylinder and run it in
put two nuts one on top of anouther and this will allow you to screw the stud in tight. Let the locktite set up for about 20 min. and then reassemble the rest of the head being sure not to use the torque wrench that got you into all this.
You will be and should be proud of yourself when this project is done as many of my friends and coustomers pay me to do just as I have outlined for you. SMILE your about to go riding again :yeehaw:
 
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#9
aahhh, you see thats where the problem lies, the stud has snapped off below the cylinder head about 5mm below the cylinder surface, so it is impossible to get at it with a vice grip or needle nose pliers. Any other ideas? :ugg: .... (Thanks for all replys allready)
 

Danman

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#11
If you decide to go the extractor route you need to get a center punch. If you center punch the broken peice that needs to be removed this will allow the drill bit to start easier without wollowing around and messing up the head. Just make sure you do it hard Also, use the biggest extractor that you can. I have used one that was to small and twisted it off in the bolt. The extractors are hardend and are very hard to drill out. One more tip for the drilling would be to use a left handed drill bit. That way as you drill the hole you heat the part up and it may spin out the remander as you will be drilling the hole "lefty lucy"

Once you get the hole in it you can heat it up and then go for the extractor (also called and easy out).
 

muddy226

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#12
blanc said:
aahhh, you see thats where the problem lies, the stud has snapped off below the cylinder head about 5mm below the cylinder surface, so it is impossible to get at it with a vice grip or needle nose pliers. Any other ideas? :ugg: .... (Thanks for all replys allready)
I think you'll probably need to drill the stud to enable you to use a stud extractor, the screw type with left hand thread, but go gently and ose the heat source to try and break the bond between stud and cylinder first, or fill the cavity on top of broken stud with penetrating agent like diesel or proper stuff and leave at least overnight to soak. One thing I would say is if you feel in danger of doing more damage at any time, stop what you're doing and take it to a professional.
 

bedell99

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#13
hello Guys,

Snapped one of my head stud today while changing my topends. I'm going to bring it to a machine shop to get it removed. I have taken many bolts out, but I don't own a drill press and don't want to damage my cylinder with a hand drill in case i slip. One quick question, Does anybody know if the studs are reverse thread on a Honda's. thank you in advance.:)

Erik
 
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#14
did the same thing on my cr125, still waiting on the new studs to come in. The studs in mine are not reverse threaded.