oh no! my 750!! :(

[rube740]

So I was changing the spark plugs and one of them snapped inside the engine. The hex part did not stay making it impossible to screw it out. It's basically level with the head! The shop told me its gonna cost me more than what the bike is worth. I have a 92 Honda nighthawk 750, any suggestions?

[coffee_brake]

How the heck did you do that?! 

I think you gotta pull the head. Pictures would help right now.
I do have a good head for the NH750, but you'd still have to pull the head so you might as well fix yours.

If you didn't strip the threads it won't be so bad. But even if you did, a Helicoil, applied correctly, will be a permanent fix.
Now if you can get the head off and remove the broken plug, then you can have a qualified mechanic put in a Helicoil and that won't cost so much, since you would bring it to him/her.

Don't be afraid to pull the head, it's not that bad. You'll want a Clymers for this, I found mine to be an excellent resource when rebuilding the Nighthawk 750. And a torquewrench. For the love of Pete, buy a torque wrench. And use it for sparkplugs as well as everything else on the motor.

[rube740]

The threads are stripped and it happened because I'm dum! Thanks for the reply this really helps. I thought the head on a 750 was a huge job? I have the clymers and I'm pretty good with tools. I'm getting a quote on the job now ill keep you updated. Thanks again

[tomb raider]

Ding dong dang, Ya how did that happen, You have a 92 or a 91, you say both 

[rube740]

92 sorry, ill fix that when I get home.

[fortyhourdays]

Like Coffee mentioned, pulling the head isn't that difficult.  I don't know how much putting in a Helicoil costs, but other than that if you have all the tools your only other expense is going to be for a new top end gasket set.

(edit) looks like a new head gasket is about $60 and a new head cover gasket is $35 here: http://www.hbhonda.com/fiche_section_detail.asp?section=124245&category=MOTORCYCLES&make=HONDA&year=1992&fveh=2966

[Soupskin]

If you take it to a shop for a Helicoil, make sure they use the Time-Sert brand, much better quality product.

If you do the grunt work and just take the head in you can get it done for $20- $50.

[rube740]

   So I spoke to a mechanic and he tells me if he has to remove the head and re thread it he will charge me up too 600$. He also said bring it to him so he can see if he can remove the spark plug without removing the head. So what do you guys think? Do it my self or 600$. And ic I do it myself I'm buying a new head.

[hppants]

1.  Don't buy a new head until you have to.  You won't know that until you (or someone) has removed the head, and deems it un-repairable.

2.  Anything the mechanic will do, you can do youself.  I would assume he is considering drilling the center of the stuck plug (NOT DEEP ENOUGH TO PENETRATE THE BOTTOM OF THE PLUG AND THEREBY INTRODUCE ALL KINDS OF CRUD INTO THE COMBUSTION CHAMBER), and then try an easy out to remove the plug.  Why don't you pull the tank and give that a try?

3.  If #2 doesn't work, read your manual and remove the head.  I know, it's intimidating and I would be super nervous trying it myself.  But with the help on this website, a good camera to take pictures, and some organizational skills (containers for bolts, etc.), I'd give it a shot and I know you can too.

I believe you are correct about 1 thing.  Running on 3 cylinders, the bike isn't worth $600.00.  So, you've got nothing to lose, and tons to gain, not the least of which is the satisfaction of knowing you did it yourself.

The 1st step is the hardest.

[floridahawk]

       Why can you just remove the tank, than used a Easyout bolt remover. Its same as if a bolt snapped off. You can do it. Just take your time. 

[coffee_brake]

I have a known good head, if the need arises...

[green427]

       Why can you just remove the tank, than used a Easyout bolt remover. Its same as if a bolt snapped off. You can do it. Just take your time. 

Except you would be drilling through ceramic material with a copper or steel rod in the middle.

[coffee_brake]

No, when you get the head off, you'll be able to get at it from the bottom side. If you are very careful and patient, I think you'll be able to turn the plug from the firing tang on the bottom. Lots of penetrating oil, maybe some heat, and even more patience of course....

[geemann]

+1 to coffee
+1 to pants

dude, this is not peer pressure. but seriously, you can do the fix yourself.  not only will you feel the pride in your own work, but your pocket will not be $600+ lighter.

trust me when i say that no one on this site would purposefully endanger the potential lifespan of a NH by conviencing them to pull the head unnecessarily. this is a very competent and helpful forum.  If you pull the head and run into an issue, we are here.

cheers,
-g

[coffee_brake]

yeah, if I can do it with common hand tools, so can you....

[helmet hair]

Cant remember if I read about it on this or another forum Im on but, have you or anyone else on here ever heard about a liquid solution that dissolves iron based metals out of alloys, came across it in relation to exhaust studs shearing off in cylinder heads, according to the write up if you mix this solution up and dunk the parts in it, it will slowly dissolve the ferrous leaving you with intact threads, assuming the threads were intact in the first place, no drilling involved.
If you want to know more I'll have a hunt around for the article, just remember to remove any other ferrous parts if you decide to try it.

[geemann]

... ever heard about a liquid solution that ... will slowly dissolve the ferrous leaving you with intact threads, assuming the threads were intact in the first place, no drilling involved...

I believe you are talking about Potassium Ammonium Sulphate, better known as ALUM, and i really do not think that would be a good idea for this situation.

HH, you are correct that it will dissolve the ferrous material.  Unfortunately, that would be the wrong material in this instance that rube would want to dissolve.  The metal around a spark plug is usually zinc-chromate, which contains no Fe to speak of.  However, I am fairly certain that the engine alloy of the 750 does contain amounts of Fe.  So, the spark plug would come free, but not because the plug "melted" away.

Not to harp, but for anyone who would like to use this method on an engine (made of aluminum or some ferrous-free alloy) to remove a broken spark plug, I would implore you to remove the head prior to surgery so that when the ALUM finally eats through the ferrous based spark plug (might be a unicorn), it will not contaminate the combustion chamber and oil supply with debris or foreign chemical agents.

Rube, have you made an attack plan yet?

cheers,
-g

[helmet hair]

  "The metal around a spark plug is usually zinc-chromate, which contains no Fe to speak of."  

Geemann, didnt know that little snipett, just shows what you can learn around here.

HH