Big Problem - Need Help Fast

[davidw2155]

I was installing a HotCams Stage 1 camshaft in my 400EX this afternoon and I ran into a MAJOR problem, at least I think it is unless someone can help me out with it. I was following the directions given on Little Sahara's website about installing the camshaft (http://www.lspsonline.com/howto/400ex%20hotcam/index.htm). So far, its the best install guide I've found online.

Now for the problem....I was removing the Cylinder head cover, removing bolts in a criss-cross pattern like it says. A few of the bolts were pretty tough, they didn't want to come out. A was extra careful on those, making sure not to put too much pressure on them so I wouldn't torque them off...or so I thought. I torqued off the two with red arrows on them in the picture.

Now for the solution, maybe. I really, really, really don't want to have to go out and buy a new cylinder head. I was thinking, I am a good machinist, I can drill out the two holes that have the bolts broken off in them, re-tap or helicoil, get a bigger bolt, and go from there? I figure if I will have to get a new cylinder head I might as well try this to see if it works or not.

What do ya'll think about that? Any advice or suggestions?

[Young_Gun1]

I have helicoiled one of them on mine before but it stripped out of the head instead of breaking it off
you just need to be careful

[honda400ex2003]

is it clean off at the base of the head? If not you could get a vise grip or something on it. i am sure you would have thought of that though. If possible you can cut a groove in it to try and get it out. otherwise, you could drill a hole in it and try to get it out with a reverse bit or an easy out. I have never had good luck with the easy outs but have with the drill bits. If you are careful if you cant get it out with a drill bit you can keep drilling it thinner and thinner until you can break it apart adn pull it out. then you could clean up the threads with the correct tap. That is what I would try first. steve

[davidw2155]

Thanks guys, I'll have to try these. They are broken off way down in there on the thread. I just finished installing the cam, but looks like I'll have to tear it all down to bring the cylinder head to a mill so I can drill out the remnants of the bolts.

[dang400ex]

Just glad its not me with this problem. haha

[Honda#4]

Man what a bummer, I can't believe that they twisted off usually there rather easy to get out but aparently that wasnt ur case. Definently do what was suggested and next time put alittle antiseize on to prevent this from happening again.

[cam19aro86]

I broke number 7. I would advise going to the hardware store and replacing all of the bolts with better grade 8 bolts, and don't you dare try to torque them to the 10 ft. lbs. that the clymer manual says, you will never get there. Just speaking from experience. Oh yeah we were tearing my buddies motor down the other day, he also broke number 7.

[dariusld]

Originally posted by cam19aro86
I broke number 7. I would advise going to the hardware store and replacing all of the bolts with better grade 8 bolts, and don't you dare try to torque them to the 10 ft. lbs. that the clymer manual says, you will never get there. Just speaking from experience. Oh yeah we were tearing my buddies motor down the other day, he also broke number 7.

Its not about how strong the bolts are, its about how strong the threads are. You shouldn't be torqueing these bolts down, thats when the problem starts. When the long ones are the problem, they are much more work than the short ones because they go all the way into the cylinder.

The lesson here is these bolts shouldnt be over tightened or you will strip some threads.

[davidw2155]

Yeah, Anti-Sieze will definately be going on all of the bolts when I get it back together. Right now I'm scouring the internet looking for some grade 8 bolts, but a M6 x 118 is a difficult bolt to find, and I think that $7.00 a piece from bikebandit is a ripoff so I guess I'll keep looking.

[davidw2155]

Originally posted by dariusld
Its not about how strong the bolts are, its about how strong the threads are. You shouldn't be torqueing these bolts down, thats when the problem starts. When the long ones are the problem, they are much more work than the short ones because they go all the way into the cylinder.

The lesson here is these bolts shouldnt be over tightened or you will strip some threads.

I had never taken the head cover off before, its been there since it came out of the factory. And the reason the long ones break instead of the short ones is because there is a much longer shank for deflection. In other words, you can be tight in the threads and keep cranking on it because its still moving, but you are just twisting the stem of the bolt instead of the threads - then thats when you snap them off.

And the long bolts have the same amount of thread as the short ones do.

[RaceinCircles]

When I snapped one, I found a kit online that makes the stronger bolts and they even have an allen head for a great fit! All mm and I've never had a problem with them snapping..I've got em on my whole outer engine. Great product. Check ebay..that's where I got em. Good luck

[dariusld]

I'm talking about the threads in the aluminum engine, not the ones on the steel bolts. I don't know if I was clear.

[davidw2155]

Originally posted by dariusld
I'm talking about the threads in the aluminum engine, not the ones on the steel bolts. I don't know if I was clear.

I know, but in this case the steel bolt was actually weaker than the threads in the engine, but I think I would have rather stripped out the threads so I could Heli-Coil it rather than having to drill them out 5 inches deep into the head.

[ae13291]

wow good thing mine dident snap when i did mine, although they were pretty tough to break loose and sounded squeaky when removing, i also used antiseize on mine now, you can try slowly drilling to one size bigger and bigger until the actual rest of the bolt comes out

[cam19aro86]

Mine didn't strip, it broke. These bolts were torqued from the factory. You need a higher strength bolt, but Im not saying try to torque the cam cover to 10 ft. lbs., and yes the manual says that is the torque rating. Oh, at the hardware store, well we have Mid-states bolt which has about every bolt you could imagine for cheap, I bought a 7mm x 120mm grade 8. It was a little long but didn't have the washer built in, so with a flat washer it ended up being a 7mm x 118mm. Honda uses a weird size bolt so you can't get them anywhere. Look for the ones about 2 mm longer without a washer.

[Gibson]

Originally posted by cam19aro86
I broke number 7. I would advise going to the hardware store and replacing all of the bolts with better grade 8 bolts, and don't you dare try to torque them to the 10 ft. lbs. that the clymer manual says, you will never get there. Just speaking from experience. Oh yeah we were tearing my buddies motor down the other day, he also broke number 7.

That's wierd, when i tore my motor down, i twisted the shank on number seven also, i wonder what's up with that:huh

[davidw2155]

We've got a pretty good Fastenal here in town, I'm gonna go check them out today, if they don't have it I finally found one online, its not a flange bolt, but it will work just fine. Honda's size is really wierd (M6 x 118) why don't they just use something standard like a M6 x 120, even though its pretty hard to find too.

[davidw2155]

So now im trying to take the head off, there are 4 cap nuts and washers and they are TIGHT! I don't want to break them off too, are there any tricks to taking these off that won't damage them or break them?

[davidw2155]

Ok, I finally got them, I set my torque wrench at 70 ft-lbs when I was loosening them before I finally got them off, they didn't want to come off.

[davidw2155]

If ya'll couldn't tell, I'm posting these as I go so if someone has the same problems they can come here and see whats up.

Well, turns out the bolts were not broke off in the cylinder head, but in the cylinder itself, which is good because now I can see them (I didn't know the bolts went all the way into the cylinder). But the bad thing is now I have to take off the cylinder...uggg. And now I will have to redo all the timing because I had to take the cam chain off too. This is turning into a bigger headache than I originally thought it would. It's ok, I'm learning...

[davidw2155]

Also, While im in here i will be replacing all gaskets, is there anything else I need to look for, check, or replace?

Originally posted by cam19aro86
I broke number 7. I would advise going to the hardware store and replacing all of the bolts with better grade 8 bolts, and don't you dare try to torque them to the 10 ft. lbs. that the clymer manual says, you will never get there. Just speaking from experience. Oh yeah we were tearing my buddies motor down the other day, he also broke number 7.

I was trying to be "professional" and going to spec one day so I decided to use the torque wrench. well it was hard to see the adjuster so what looked like 7ft lbs was 9ft lbs and as i'm saying i dont want to go anymore or they will snap and at that moment it snapped and clicked fo 9ft lbs lol they should have used bolts that are threaded to the head. They usually snap were the threaded part meets the unthreaded or were the case meets. They made the bolts snap so the treads dont pull out of the motor which is smart but maybe going to a 10mm bolt would have been a much better idea. The thing you forget is the extra torque put on the bolt from the length of it. The longer the bolt the more torque at the end. Ratchet/sockets are a horrible idea for tightening engine bolts unless they are torque because of the extra leverage and you cant feel for the bolt. I always remove with a socket and install with a regular wrench. like mentioned try making a slot to put a screw driver in or drill a hole and tap in a bit with a hammer and back out with a drill. I just did that with my footpeg bolt and it worked great.

[davidw2155]

Thanks for the advice. I just got back from the machine shop, got them both drilled out and one of them cleaned out, but I've got a lot of stuff to do tonight so I had to call it quits early. I think they will work, at least the one that I cleaned out looked OK, we'll see.

Mine snapped off right where the thread meets the shank of the bolt, right on the top of the cylinder. I found some Grade 8 bolts online, I'm going to get three of them and replace the one I didn't break as well because I'm sure this won't be the last time this engine is in pieces and I don't want to run into this again.

I just wish I had the money to bore it to a 416 now that I have it all apart. Guess I'll just have to wait.

[dang400ex]

I think you should go ahead and do the 416 or the 406 kit. Sooner or later your gonna do it anyway. And you know you need more power.

[davidw2155]

Originally posted by dang400ex
I think you should go ahead and do the 416 or the 406 kit. Sooner or later your gonna do it anyway. And you know you need more power.

Are you gonna pay for my upgrade right now? And don't worry about power, I got plenty :D