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Heads and Cylinders All about your porting, compression, rings, cylinder and piston modifications to your bicycle engine

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  #1  
Old 03-22-2009, 04:16 AM
Fletchsd80 Fletchsd80 is offline
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Default Help- Tightened head bolt too much!

After having black stuff leaking out of either the head gasket, or the spark plug hole today when I got my engine running for the first time (probably oil although it was black like the grease?); I got out my torque wrench and tightened the head bolts to 13 pounds. A little while later I decided to try and up it to 17 just to be safe. One of them either stripped or broke off because it just turns endlessly now. I immediately lowered the others down to 15.

Does anyone know where I can get a matching bolt? Spookytooth has the entire head assembly, but I'd hate to have to pay for that when I just need the bolt. I will open it up tomorrow and see if it broke off or was just stripped.

Earlier when I took off the head, two of the bolts stayed in and the nuts came off, and two of the entire bolts came out with the nuts...is that supposed to happen? Are those broken as well? If they were broken I would assume that you couldn't tighten them when you put them back in?
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Old 03-22-2009, 07:02 AM
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spad4me spad4me is offline
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Default Re: Help- Tightened head bolt too much!

Sick bike parts sells a stud replacement kit.
There are two sizes 6 mm and 8 mm.
Or you can make your own using threaded rod purchased from Ace, Lowes.
I hope it just snapped off and did not strip the engine threads.

All of the nuts bolts and fasteners that came with your kit are really cheaply made..
The nuts and bolts holding my rear sprocket on.

Broke off one day. LOL

Last edited by spad4me; 03-22-2009 at 07:04 AM.
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Old 03-22-2009, 05:23 PM
Fletchsd80 Fletchsd80 is offline
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Default Re: Help- Tightened head bolt too much!

THanks Spad,

I went to try and get the head off, and that damn thing must be stripped because I turn it endlessly without it loosening! I'm at a loss now as to how to get the damn thing out of there? I have to get the head off or I might as well buy a whole new engine!

BTW I've had those sprocket bolts break on me too.

Last edited by Fletchsd80; 03-22-2009 at 05:24 PM. Reason: adding something
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Old 03-22-2009, 05:43 PM
toytime toytime is offline
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Default Re: Help- Tightened head bolt too much!

Were going to have to get you a smaller set of tools. If you can't get that stud out,force it upwards. Use vice grips if you have to. It will come out. I have the feeling you have those acorn nuts.

Last edited by toytime; 03-22-2009 at 05:47 PM.
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Old 03-22-2009, 05:54 PM
Fletchsd80 Fletchsd80 is offline
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Default Re: Help- Tightened head bolt too much!

Quote:
Originally Posted by toytime View Post
Were going to have to get you a smaller set of tools. If you can't get that stud out,force it upwards. Use vice grips if you have to. It will come out. I have the feeling you have those acorn nuts.
I do have the acorn nuts, and when I could barely grab a hold on it with the pliers to try and lift up on it, the acorn part (round top) came off. So now I just have a regular nut that won't come off. I can't tell if the post is turning with the nut or not. It would be great if all it was was a stripped nut and not a broken or stripped post.

I am not very mechanically knowledgeable as far as tools go. So I need vice grips? Anything else? If I force the whole post out, won't I definitely strip the engine threads?

Thanks
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Old 03-22-2009, 06:12 PM
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Norman Norman is offline
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Default Re: Help- Tightened head bolt too much!

to repair stripped threads in the block you can use a device called a helicoil thread repair kit sold at most auto parts stores should have them for metric and american the directions are in the kit or if you want to replace all the studs with american you can tap the block for the american thread
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Old 03-22-2009, 06:37 PM
toytime toytime is offline
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Default Re: Help- Tightened head bolt too much!

It sounds as if the nut may have stripped. I only say that because you say it turns but won't come off. It should be so easy for you to see what is turning. Use a wrench so that you can see the parts as you turn. This can be fixed so don't worry. Do you own a set of vice grips?
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Old 03-22-2009, 07:15 PM
Fletchsd80 Fletchsd80 is offline
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Default Re: Help- Tightened head bolt too much!

Quote:
Originally Posted by toytime View Post
It sounds as if the nut may have stripped. I only say that because you say it turns but won't come off. It should be so easy for you to see what is turning. Use a wrench so that you can see the parts as you turn. This can be fixed so don't worry. Do you own a set of vice grips?
The head is still on because I cannot get that nut off. I can't see if it is turning the post with it because the washer and lock washer are in the way and it is not high enough up to see the post. I don't own vice grips, and I cannot grab the post at all.
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Old 03-22-2009, 07:18 PM
Fletchsd80 Fletchsd80 is offline
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Default Re: Help- Tightened head bolt too much!

Quote:
Originally Posted by Norman View Post
to repair stripped threads in the block you can use a device called a helicoil thread repair kit sold at most auto parts stores should have them for metric and american the directions are in the kit or if you want to replace all the studs with american you can tap the block for the american thread
That's good to know thanks Norman! Now at least I know I don't have to order a new engine. I stil need to get that nut off though. I'm thinking of just taking it into a machine shop. Maybe I can get the threads fixed in the block if they are damaged there as well. I have no idea what they would charge for that.
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Old 03-22-2009, 07:29 PM
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Pablo Pablo is offline
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Default Re: Help- Tightened head bolt too much!

Yes we sell a full kit like this:

Sick Bike Parts

So the nut spins on the remaining stud, but won't even come off? Wow that be stripped. A couple things come to mind since you can't get a nut splitter in there. Easiest would be to remove all the other nuts, have a buddy pull up on the cylinder while you turn the wrench in the reverse direction....this should put enough pressure under the nut to get it off. If that doesn't work, grind the nut off with a moto tool....or grind slot in the top of the stud and use a big screwdriver to take the stud out.

Indeed our studs are high grade 8.8 and nuts are good quality to prevent this hassle.
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