Broken Valve Cover Bolt

[Red 250]

First off I have a 2007 Honda CRF 250
Well my nephew checked my valves for me ( which were within specs) He put the bike back together for me as well. I was out of town and everything was good until I went riding the other day and noticed oil on my boot. Luckily we were close to the truck and when we stopped there was oil all over the front of the engine. We loaded up and came home I tore the plastics and gas tank off and I look down on the valve cover and I am missing a bolt so I figure ok were good just buy a new bolt and all is well. Well on closer inspection I notice that the bolt had broken off in the cam (sorry I am not sure what to call this part) But it is the piece that holds the cam in place. it has 2 bolts that hold the bearing in place and one bolt hole that holds the valve cover in place. Now I went down to the local shop to get a new one since it should be a simple part to replace. NO such luck they tell me I have to buy a whole new head because they don't sell just that part. What gives ?? Can this be true?? I was amazed that this part is only available if you buy a new head.
Can anyone help me out and make a few suggestions to help me figure out what to do. This bike is only 6 months old and I don't have the cash to buy a new head. Thanks.......................Red

 

[btm1948]

might have a way to fix that broken bolt

i dont know if it is possible but you might try using an easy out. or try drilling out the bolt. good luck with that and i hope you can get it fixed.


Ben

 

[rmc_olderthandirt]

I was amazed that this part is only available if you buy a new head.
Thanks.......................Red

Yes, this can be true.

I don't know your bike at all but from the descriptoin it sounds like the bolt is broken off in the piece that forms/holds the bearing for the cam.

This is a common arrangement and while the piece looks as if it could just be replaced it is actually a matched set with the head. When the head is made the raw parts are bolted together and then they are machined so that the bore for the cam is perfectly straight and within tolerance. If you replace it with another one (such as off a bike being parted out) it will mess up the "match" and could lead to major problems down the road.

Is there any part of the broken bolt that you can get to? If there is enough to get a pair of vice grips on it could be removed that way. If there is any part of the screw at all sticking up you can use a Dremel tool to grind a screw driver slot in the top. Otherwise, use a center punch to create a starting dimple, then drill a small hole and insert an easy-out (get the easy out first so you know the proper drill size)

Note that these operations will put a lot of metal filings all over the place so either drap rags over everything as a shield or wash the top with a mild solvent when you are done.

If that all fails then you need to pull the head and take it to a machine shop and have them remove the bolt for you. I recommand strongly against just pulling the block off and taking that to the shop as I suspect that those blocks should never be removed.

Rod

 

[_JOE_]

I would imagine from the design of the bolt that it brok off flush with the top of the cam cap. As mentioned an easy-out could work or a small slot ground in for a screwdriver. The cap can be removed by takng out the two bolts on either end, it holds the roller cam bearing. Watch out for the small retaining ring under the cap. The bolt that broke is very small and only takes 10nm of torque(7ft lbs/88in lbs). A quality torque wrench is vital to servicing this engine by yourself. Good luck!

 

[Red 250]

Unfortunatly the bolt is broken off below the top of the hole it is screwed into. I am taking it in tomorrow. They said they can extract the bolt so we will see. I had to take the piece off . I made sure to place each part out so I didn't mix things up..... I understand about the machining it is just upsetting to have this issue after only owning the bike for 6 months. I would have used the torque wrench if I was there but thems the breaks. .....thanks all for the help. .............Red

 

[Ol'89r]

Red.

The cam caps are marked "R" and "L" with a little arrow pointing to the intake side.

Before you try an easy-out you may want to try a tig welder. A tig welder can weld a little bead to the top of the broken bolt until the bead protrudes out of the hole enough to weld a nut to it and unscrew it. We do this all of the time here in my shop. Once the stud is drilled off center or the easy-out is broken off in the stud, you're screwed. I would try a tig welder first.

Where are you located? I could do it for you if you can't find someone in your area to do it. Just PM or email me for an address to ship it to.

Also, be sure to take Joe's advice about the torque wrench. Only use an inch pound torque wrench. A foot pound torque wrench is not sensitive enough.

 

[Red 250]

Hey thanks to everyone who responded. I took it in today and the local guys had the bolt out in about a half hour. They had to drill the top out a bit. There are a few less threads but it looks like it should work. I put the bike all back together but didn't torque anything down yet. I will do that tomorrow. I want to be extra careful about the right torque for all the bolts I removed. I ordered a new bolt and rubber washer for the valve cover and that should be in by Tuesday of next week. So no riding for me this weekend but if all goes well my bike should be ok for the future... Thanks again for the input.............................Red