Taking the head off (and putting back on)

[bayrider]

Hi folks,

  Kinda long post, I hope it's not too rambly.

  The background: a few weeks ago, when adjusting the valves, I undid two camshaft cap bolts (different caps, both holding down the timing chain guide), and they weren't easy. Turns out I stripped the threads in the head which they screw into, and I couldn't get them torqued back to spec. It's fixable, I know, but I really didn't want to disassemble things further. The bolts are 46 mm long, and the holes they thread into are more like 54 mm deep. So I got 50 mm bolts, and one of them torqued down. The other stripped further. Well, I've kept the head cover on at night when I'm not working on it --- don't want the spiders getting in. Today I took the cover off, played around a little, and then noticed I didn't have one of the dowel pins in the middle of the head cover. They were both stuck into the head pretty good, so I got complacent with checking them, but sure enough it's gone. I've spent about an hour with a flashlight looking in there, and I don't see it, so I fear it's dropped down the center.

Maybe I'm wrong, but I don't see a solution to this in which I don't take the camshafts out. I figure at minimum I've got to get the timing chain and gears out of the way if I want to find the pin down at the bottom. And I figure if the camshafts are coming off, I might as well take the head off and actually fix those stripped threads. heck, they might all be stripped at that point. Sounds fun, but I have two fears:

  1) I strip the actual head bolts when taking the head off. In that case I've got to take the bottom end out, and then I'm getting out of my comfort zone.

  2) There is a problem remating the head during reinstallation. Haven't seen it said here, but on the EX500 forum I think, but my understanding is that if the head comes off, let's say for a new head gasket, the surfaces really have to be lapped before being remated. Something about the design of this engine, with the timing chain running in the middle, being "flimsy" when disassembled, and that leads to bad mating and gasket blows if it's just stuck back together. Maybe that's BS, you tell me.

  So I've got three questions, for any folks who can weigh in:

  1) Could I come out of this without removing the camshafts? The still-stripped thread is a toss-up on a yet-longer bolt doing the trick, but if the missing dowel pin is down the center, is there even hope of just getting it with a magnet?

  2) If I take the head off, should I be worried about stripping the head bolts?

  3) If I take the head off, do I need to take the bottom end out and lap the surfaces before remating? I'd probably throw a new head gasket in there, if it's open, but I don't think I can do a lap-job myself and I fear that having it done otherwise will be a pain, at best.

  Thanks for any help.

[bayrider]

Updating for any unlucky folks who find themselves curious how this turned out... I ended up getting the dowel pin back. It was down in the central valley, and just needed a bit more coaxing to come out. Patience is key. As for the cap bolts that caused my crisis: I got hold of some 55 mm bolts, and my neighbor helped me cut them down to 53 mm. The book says 104 in-lbs, but apparently that's a mistake --- the forum was 87 in-lbs, so that's what I went with. Man was I sweating on the last few turns!

  So I'm a little lucky, and didn't need to do further disassembly. I did run into a pretty major coolant leak at the valve cover, but new o-rings on the coolant pipes (should be 14mm, but it was easier to get #11 where I'm at) fixed that up for me, and broke a terminal on the thermostat ground line, but that's also an easy fix. I also found that one of the valve cover bolts is gnarled to all heck. Ran it through a die, but it's toast, so I'll need to replace that. Still, I started it up and we're sounding pretty good.

And to think, I already ordered a replacement head on ebay, and a little f-ing (read: pricey) plate to lap it with. I guess if I do need/want to do a rebuild, I'll be ready to go. Cheers folks, ride safe.