Crf250x/r head bolt broken(pics)

[Crf250x kid]

I'm 15 and I have a 2006 crf250x and I just sent my head in to get a valve job. I just got my head back and decided to start the rebuilding process.

I started off with the cylinder and got all that installed.

Now that I have the cylinder installed, I put the head on.

The head and cylinder are now on. Time to tighten down the cylinder and head to the bottom end of the engine. Remember, the manual says 29 foot pounds.

Ok so I know how to use a torque wrench I'm no dumbass. Okay everything's going smooth and I'm really excited for this weekend when all of the sudden this happens:

So, with that being said, I tracked down the engine blow up picture online and found out that the part is part number 14 on the picture below.

Well folks, tomorrow is the big day. I get to order 4 more bolt/studs (the part that broke), and I have to order 4 new acorn nuts.

One more question: it says that the bolt/stud threads are 10mm and the acorn nut is 9mm. That is what it says online. Is this accurate? I would think that they would be the same mm.

Also, the acorn nut screwed on to the bolt too much, causing the blot to go through the top of the acorn nut(as seen in picture 8). That is wrong.

Finally, I can put a pair of locking pliers and spin the broken bolt(bottom half of the bolt in picture9). I am scared to keep spinning in incase I could strip the threads that the very bottom of this bolt is threaded into. I'm wondering If I could just twist it out and then twist a new one back in.

Thanks!!!

Edited April 17, 2014 by Crf250x kid

[Crf250x kid]

Bump

[martin truszkowski]

hi that bolt was stretching and bottomed out in the nut then twisted of but your having a go at getting it back together so fair play to you young lad,use a good quality locking plyers to remove the bit that is left in the case to help to remove it use a propane tourch to heat the area around the stud get the case area good and hot and that broken piece will come out much easier.Martin.

[Crf250x kid]

hi that bolt was stretching and bottomed out in the nut then twisted of but your having a go at getting it back together so fair play to you young lad,use a good quality locking plyers to remove the bit that is left in the case to help to remove it use a propane tourch to heat the area around the stud get the case area good and hot and that broken piece will come out much easier.Martin.

i figured everything out. Thanks for your advice. I got a pair of vice grips on it and twisted it out. I'm going to need 4 new studs and 4 new acorn nuts. I used a little ingenuity to figure this one out. Damn, I think I'm the master at taking top ends and cylinders out now. Just waiting on the parts now. I'm going out this weekend and I'm leaving tomorrow and my bike is in pieces. I hope I don't break anything else or I'm gonna blow a head gasket.

[The Inquisitor]

I looked at both OEM's for the cylinder and head for the 06 250X.

 

1) Probably not a big deal overall BUT you do need know the VIN of your bike to pick the correct info.

 

2) I would not assume that the part's for an X and an R are the same.

 

3) With that said, what I see for a 06 250x A.......

4) And I wouldn't confuse the description from below with the size of an actual wrench or socket.

# 16 - 90232-MB6-680 NUT, CAP (9MM) - I've never done my head BUT from your pic's I can't see that this is 9MM (either thread size or outside nut size.

# 14 - 90031-KRN-670 BOLT, STUD (10X135) - This doesn't look like 10MM either.

I'd be really surprised if the OEM part's aren't correct since these part number's are 7 year's old.

I'm a bit shocked the stud sheared but.... is there any way your torqe wrench is messed up or not set correctly??

If the nut bottomed out on the stud BEFORE it reached 29 ft-lb, then something is not right. see below

As far as removing the stud's, As martin said and maybe also soak with some penetrating fluid, BUT they may be for some reason reverse threaded into the cylinder (maybe why the nut bottomed out). You could wait until you get the new stud's or maybe someone else can confirm.

Only tip's I've got - Loctite where you need Loctite, anti-seize where you need anti-seize.

You could also try this in the 250X forum in case this is an x issue

I'm stoked your doing this yourself dude!!!! Good luck - hope you get out and rip for the easter weekend

Edited April 17, 2014 by filterx

[Go Big Red]

i figured everything out. Thanks for your advice. I got a pair of vice grips on it and twisted it out. I'm going to need 4 new studs and 4 new acorn nuts. I used a little ingenuity to figure this one out. Damn, I think I'm the master at taking top ends and cylinders out now. Just waiting on the parts now. I'm going out this weekend and I'm leaving tomorrow and my bike is in pieces. I hope I don't break anything else or I'm gonna blow a head gasket.

First of all, congrats on doing the project yourself.  This stuff happens to all of us, and will probably happen to you again.  It just does, but you move on and keeping plugging along.

 

Second, X and R head are very similiar.  It is a common mod for X owners to replace their head with an R head.  It slips right on and used the same hardware for most bikes from 2004 to 2007 and probably 2008

 

As far as why this happened, it could be a number of things.  Previous owner might have over torqued and stressed the stud.  Your tightening might have just been the last time that the bolt could take that kind of stress.  The engine, in its life, could ahve been overheated to where it changed the strength of the stud.  Very unlikely, but plausible.  In any case, if you ordered the studs and nuts for your bike from a dealer or off the Honda parts fiche, they will be the correct parts.  Install them to the coret torque specs and you will be fine.

 

Good call on replacing all four.  If someone over torqued one, the others probably got the same treatment.  And do double check your torque wrench.  29 ft/lbs is not a not, but that is a long and skinny stud.  

 

Now, get the parts, get it fixed, and enjoy the fact that you did the work and the bike runs because of what you did.  Wish I would have been smart enough to tackle projects at your age.  You are well ahead of the game when it comes to enjoying bikes for a lifetime. ?

[Crf250x kid]

I looked at both OEM's for the cylinder and head for the 06 250X.

1) Probably not a big deal overall BUT you do need know the VIN of your bike to pick the correct info.

2) I would not assume that the part's for an X and an R are the same.

3) With that said, what I see for a 06 250x A.......

4) And I wouldn't confuse the description from below with the size of an actual wrench or socket.

# 16 - 90232-MB6-680 NUT, CAP (9MM) - I've never done my head BUT from your pic's I can't see that this is 9MM (either thread size or outside nut size.

# 14 - 90031-KRN-670 BOLT, STUD (10X135) - This doesn't look like 10MM either.

I'd be really surprised if the OEM part's aren't correct since these part number's are 7 year's old.

I'm a bit shocked the stud sheared but.... is there any way your torqe wrench is messed up or not set correctly??

If the nut bottomed out on the stud BEFORE it reached 29 ft-lb, then something is not right. see below

As far as removing the stud's, As martin said and maybe also soak with some penetrating fluid, BUT they may be for some reason reverse threaded into the cylinder (maybe why the nut bottomed out). You could wait until you get the new stud's or maybe someone else can confirm.

Only tip's I've got - Loctite where you need Loctite, anti-seize where you need anti-seize.

You could also try this in the 250X forum in case this is an x issue

I'm stoked your doing this yourself dude!!!! Good luck - hope you get out and rip for the easter weekend

thanks for your input I appreciate it. Yeah my parts will be in tomorrow and I'm leaving tomorrow

[Crf250x kid]

First of all, congrats on doing the project yourself. This stuff happens to all of us, and will probably happen to you again. It just does, but you move on and keeping plugging along.

Second, X and R head are very similiar. It is a common mod for X owners to replace their head with an R head. It slips right on and used the same hardware for most bikes from 2004 to 2007 and probably 2008

As far as why this happened, it could be a number of things. Previous owner might have over torqued and stressed the stud. Your tightening might have just been the last time that the bolt could take that kind of stress. The engine, in its life, could ahve been overheated to where it changed the strength of the stud. Very unlikely, but plausible. In any case, if you ordered the studs and nuts for your bike from a dealer or off the Honda parts fiche, they will be the correct parts. Install them to the coret torque specs and you will be fine.

Good call on replacing all four. If someone over torqued one, the others probably got the same treatment. And do double check your torque wrench. 29 ft/lbs is not a not, but that is a long and skinny stud.

Now, get the parts, get it fixed, and enjoy the fact that you did the work and the bike runs because of what you did. Wish I would have been smart enough to tackle projects at your age. You are well ahead of the game when it comes to enjoying bikes for a lifetime. ?

i thought it was weird how the stud went through TWO of the acorn nuts. Ten, the nuts are a special part that I can't get at Home Depot, more of my time wasted. All I can do now is sit tight and pray that nothing else gets broken. . I hope I get to shred it up in ocotillo wells this weekend! Yeah I have been interested in engines and motors all my life, so I self taught myself on YouTube and whatnot. I actually just figured out how engine work last year

[The Inquisitor]

OK I'm assuming your got a Clymer or similar manual for doing your work.

As well, I'm not a professional mechanic so........

Did you order your part's on line or through a Honda Dealer. I do most of work myself on both Yamaha on Honda's and my local dealer's have been really good when I've needed advice etc.

Replacing the stud's - My Clymer does not explain this. I can't see that it would hurt to put oil on the thread's going into the engine BUT with that said a light lube or maybe a little good quality grease (which you should have anyway) might not hurt. I would also buy a can or 2 of compressed (come's in handy for lot's of things if you don't have compressor) and carefully blow out the hole's. Make sure the piston and any critical area's are covered to prevent crap getting in.

I would follow this vid even thought it's for an exhaust on a car block.

Hardware - Our bike's are metric and some of the hardware (nut's and bolt's) are somewhat specific as you found out. I bought a Japanese bolt kit from my dealer for about $25.00 which helps for most common hardware but most likely not for larger stuff like the stud bolt's. You need to make sure you use the correct thread pitch (ie fine etc) I would take one of the new stud's to an Automotive shop (Napa or something) and have them size a couple of correct nut's so you can install the stud's as per the above vid. DO NOT use the in-correct nut's and cross thread when installing the new stud's or your hooped!!!. Use the OEM nut's to install the head since they are acorn style for a reason.

Once you get it back together and running - Use Maxima Maxum 4 Break-In Oil and maybe the old filter if it's not too dirty or new worse cast. Let it run on idle until the bike warm's up. Stop it ASAP if anything sound's weird. This maybe over kill BUT I would run it for 10 or 15 min, then drain the oil and replace the oil and filter. If thing's are running right, doing and oil & filter change right away will help in case there was any metal shaving etc left over from the re-build. You just spent a bunch of time and cash on your re-build so oil and filter is cheap in the bigger picture. (think ya got this covered).

Giving her a good clean once it's running will help to see if anything's leaking.

I have a 05 250R.I run an hour meter, magnetic oil drain bolt and use Maxima Synthetic Blend 4-Stroke Oil. I change my oil 10 to 15 hour's and check every ride and change if oil looks really dark. Change oil filter every 2nd change and tranny oil (Maxima) every 2nd engine oil change. Keeping track of your engine hour's, keeping the air filter clean and doing regular oil changes is the best advice I can give on keeping your motor in top shape.

I too grew up with just a mom and did my first complete car engine re-build when I was in grade 9 auto. Luckily I had some good guy's around who took me under there wing..

If your REALLY stuck I'm on-line tonight for awhile and some Friday. Send me a PM since this thread may get a bit long

Edited April 18, 2014 by filterx

[Crf250x kid]

OK I'm assuming your got a Clymer or similar manual for doing your work.

As well, I'm not a professional mechanic so........

Did you order your part's on line or through a Honda Dealer. I do most of work myself on both Yamaha on Honda's and my local dealer's have been really good when I've needed advice etc.

Replacing the stud's - My Clymer does not explain this. I can't see that it would hurt to put oil on the thread's going into the engine BUT with that said a light lube or maybe a little good quality grease (which you should have anyway) might not hurt. I would also buy a can or 2 of compressed (come's in handy for lot's of things if you don't have compressor) and carefully blow out the hole's. Make sure the piston and any critical area's are covered to prevent crap getting in.

I would follow this vid even thought it's for an exhaust on a car block.

Hardware - Our bike's are metric and some of the hardware (nut's and bolt's) are somewhat specific as you found out. I bought a Japanese bolt kit from my dealer for about $25.00 which helps for most common hardware but most likely not for larger stuff like the stud bolt's. You need to make sure you use the correct thread pitch (ie fine etc) I would take one of the new stud's to an Automotive shop (Napa or something) and have them size a couple of correct nut's so you can install the stud's as per the above vid. DO NOT use the in-correct nut's and cross thread when installing the new stud's or your hooped!!!. Use the OEM nut's to install the head since they are acorn style for a reason.

Once you get it back together and running - Let it run on idle until the bike warm's up. Stop it ASAP if anything sound's weird. This maybe over kill BUT I would run it for 10 or 15 min, then drain the oil and replace the oil and filter. If thing's are running right, doing and oil & filter change right away will help in case there was any metal shaving etc left over from the re-build. You just spent a bunch of time and cash on your re-build so oil and filter is cheap in the bigger picture. (think ya got this covered).

Giving her a good clean once it's running will help to see if anything's leaking.

I have a 05 250R.I run an hour meter, magnetic oil drain bolt and use Maxim oil. I change my oil 10 to 15 hour's and check every ride and change if oil looks really dark. Change oil filter every 2nd change and tranny oil every 2nd engine oil change. Keeping track of your engine hour's, keeping the air filter clean and doing regular oil changes is the best advice I can give on keeping your motor in top shape.

I too grew up with just a mom and did my first complete car engine re-build when I was in grade 9 auto. Luckily I had some good guy's around who took me under there wing..

If your REALLY stuck I'm on-line tonight for awhile and some Friday. Send me a PM since this thread may get a bit long

thanks! I'll contact you if I have any issues. It's pretty impls though

[The Inquisitor]

Cool

 

I justed edited my last post re oil

 

One more thing....

 

Once the stud's are installed, you should measure from the head to the top of the stud to make sure they are all the same length. (might a have been a good idea to do this before you took them out but..)

 

I could not find a spec as to what this distance should be BUT if one stick's out way farther that the rest for example, the acorn nut will not tighten that side of the head correctly. This may be obvious

Edited April 18, 2014 by filterx

[Crf250x kid]

Cool

I justed edited my last post re oil

One more thing....

Once the stud's are installed, you should measure from the head to the top of the stud to make sure they are all the same length. (might a have been a good idea to do this before you took them out but..)

I could not find a spec as to what this distance should be BUT if one stick's out way farther that the rest for example, the acorn nut will not tighten that side of the head correctly. This may be obvious

i only removed one of four studs. I see what you mean, I'll take that into consideration tomorrow evening. Thank you

[Garage_Dog]

I ran across this thread while searching for cylinder stud removal.

The part # states a 10mm bolt because that is the size of the threads that go into the cases.  The other end where the acorn nuts bolt onto are 9mm.  I searched high and low and it is very difficult to find 9mm nuts.

I wonder how things worked out for the OP?