I spent all day long removing the head to replace the head gasket on my friends 400ex. We get almost done and are putting on the head cover and one of the suckers STRIPS!!! with like no pressure on it, it strips. This is bad, so we put some super strength loctite on it and put it in for a temp fix. Next we get about 4 more torqued down. Move on to one of the long ones and the sucker snaps!!! and the end breaks off. All this at 8ft lbs of torque!!!!. My God, how weak can a bolt be??. Thats the last straw, Im not taking the head off again to get to the stupid little bolt that broke off, only to have some more break by the time we get ready to put it together again. The stripped one sucks too. Friggen 10 hours of work for NOTHING!!!. I told him to take it to a shop or wait about a month till I get up enough nerve to mess with it again.

 

o man that kinda stuff REALLY tics me off...sorry dude!!

 

my motor is still broke...has been for a few months now because of dumb stuff like that...[img]i/expressions/face-icon-small-mad.gif[/img] errrr

 

A general rule of thumb when doing motor work like that is to replace all the bolts with new, high quality stuff and also run a tap through all the threads to make'm nice and clean when installing the new hardware. This usually helps avoid the nasty encounter you've had. Sorry to hear about that, I know how much it sucks.

 

that could cost alot, there are 12 head cover bolts and tons of other ones. Honda seems to like to use a ton of little weak bolts instead of a few big strong ones like yammy. I told him before ill even consider helping working on it, he has to get all new head bolts. Any ideas on how to get the one out that broke off inside? It was one of those really long ones that go way down inside the head [img]i/expressions/face-icon-small-sad.gif[/img] Probably 5 inches long. Im trying to figure out of theres a way without taking the head off again.

Why cant it be like my warrior engine? lol. It reminds me of a harley engine or a american car engine. Everything is big and its not compact. It would actually be a big motor if the stroke wasnt so short. Get into that 400ex engine and I feel like im playing with with a compact easily breakable swiss watch or something.

 

We've had alot of problems with that on our '98 CR 125. Just tightening bolts to spec and they snap. It's not easy finding some of the metric sizes to replace them either. Several times I have had to go back to the dealer and order a bolt or screw. Pain in the butt. Just make sure you watch out for readings in inch/pounds instead of foot/pounds which can be easy to miss sometimes.

 

Alot of the time you twist the bolt when you take it out. Then when you put it back in it twist the other way and breaks. Look at the bolt before you put it back in if it looks funny scrap it. To help stop the problem of twisted bolts hit the bolt with a hammer as you are trying to break it loose. When puting the bolt back in make shure there is no oil in the hole or on the bolt or you will strip the threads about every time. Oil on the threads give you a wrong tork reading.

 

Good information worth repeating.

Chet[img]i/expressions/face-icon-small-wink.gif[/img]

 

Just as crawdad said are you sure your using a mini torque wrench that measures inch/pounds? Not full size that measures Ft/lbs. Even if you dial that full size torque wrench in correctly the leverage you get on the full size is going to cause you to tighten the bolts alot more than spec.

 

We were using both a full size ft lb clicker model and one with a guage as a spare. All the specs in the manual were in Ft lbs except the ones for things that require a screw driver. Also we were taking it real slow, the sucker snapped at around 6 or 7 ft lbs id say, was expecting it to click any second and I thought te snap was a click. Thats the second bolt we've had snap. They are just generaly weak, 7ft lbs!! I could wrap a glove around it and exert that much with my hand and twist it to break it.