So i decided to check my valve clearance today, intake valves are good 0.05, but my exhaust were tight, now here is the problem, as i was holding down the bucket on the right side exhaust valve to remove the shim to measure, it slipped, so i tried to turn over the engine to try again, and it only went so far and stopped, upon inspection, it looks like the exhaust valve fell into the cylinder( can see it through the spark plug hole).

Has anyone had this happen before? what would cause it?

I now have the motor removed (with the exhaust on because the 2 inner exhaust bolts are stripped) I was wondering what size bolts hold the exhaust on?

on the bight side it gives me an excuse to re-jet (carbs are off already) and do any other maintenance.  I was wondering what i should look at now that the bike is apart

Its an 03 with 37000 km

thanks in advance
Dave

The only thing I can tell you for sure is that the exhaust bolts are 8mm, I think. They're probably about 40mm long.

I've got the same problem with my exhaust bolts, but all 4 are seized. Very badly.
How are you going to free yours?

Also, I just ordered new bolts from bike-bandit with my last order, they were fairly inexpensive. No idea about the size.

the 2 inner exhaust bolts are seized on my GS as well.

I tried everything to get them off and have since given up before I snapped them.

I know people have ended up breaking them off inside the head and I would rather not have to deal with that.

If you figure a way to get them off let me know.

I tried a hex socket, and vice grips I also tried soaking them with penetrating oil a couple times a day for about a week combined with heat cycles from a torch.

I had the same problem, ended up braking both inside the head..... was not a fun experience. I sucessfully drilled and retaped one bolt, but the other.... it ate my drill bit.

If you've got access to, weld a piece of metal to the bolt and use it as leverage. Thats worked for me in the past with stuck bolts.

Conoral11

So i got the inner exhaust bolts out, picked up the irwin socket style bolt extractor, just tapped it on with the hammer and turned them out,


As for the motor this is what i found inside the left cylinder


now i just need 4 new exhaust studs, a new exhaust valve, some new fuel line (tore some taking it all apart), and Ill be set.

as well as 2 255 shims for the exhaust valves

exhaust valves for the GS are EXPENSIVE!. Not as bad as those for an R1, but still ~45 per valve. I did the same thing inadvertantly, but my issue came from messing my timing up and pushing the bike around in gear (accident). Good luck with your repair.. lots of pictures!

I am amazed it broke like that. I am wondering if it hit something and what else has been smacked in there.

I think it broke when the valve snapped back into position, i was holding the bucket down and rotating the crank move the cam away from the shim, the driver slipped and it snapped back into position, the motor hasn't run with it broke, just moved enough to remove the cams.

all in all the motor actually looks good for having 37000 kms on it

luckily the weather is crap lately, 1 or 2 degrees C, so i wont miss to much riding weather
here is a pic from a few weeks ago, i thought it turned out good

If you turn the engine while holding a valve open it will break an exhaust valve off like that when it hits the other valve and/or the piston.  I had a sticking bucking on my 02 GS that I was aware of after my first valve check.  Since it would free up and run smoothly 30 seconds after start up when it began to heat the head I decided to let it go hoping it would free up with miles.  It didn't and it stopped with a bang while cranking the engine to start it one freezing winter morning.  After tearing it down I could see the broken exhaust valve had hit the edge of the intake valve and the top of the piston when it stuck wide open that cold morning.




I repaired my engine with 20k miles on it and have had almost 60k more trouble free miles from it as I approach 80k miles now.

Quote from: gsJack on April 18, 2010, 02:59:35 PM
I repaired my engine with 20k miles on it and have had almost 60k more trouble free miles from it as I approach 80k miles now.

Thats good to know, thanks for the reply

RE: stuck exhaust bolts

Part of the problem is the limited clearance.  Take the forks off the front end so you have room.

If you really want the bolts to come off, here's what I would do:

Get a handheld impact driver for ~25.  These are outstanding tools and you won't know how you lived without one.  They're absolutely essential for older bikes that use philips fasteners on the engine and throughout the bike.

Get a hex driver socket that fits the exhaust bolts, put the socket on the impact driver.  An alternative is to buy a cheap hex wrench set and cut the angled portion off with a dremel.  Then you can put the straight portion in a socket you already have and use it like a hex socket.

With the impact driver you'll almost certainly have the bolts out in a couple whacks with a hammer.

+1 for seized bolts hit them with a hammer a few times and either impact them or use old man strength.  thats how my teacher always does it.  old man strength and some splooge.  if you dont have old man strength then fit a long pipe over a rachet to get more leverage. if its stripped you can always drill it out carefully or use bolt extracter pictured above. i got a craftsman one of those cause craftsman kicks irwins ass

use anti-seize on the bolts to prevent seizure

So the motor is back together, ill find out tomorrow if it will start, i think the hardest part was just getting the motor back into the frame, still have to install sub frame, motor mounts and gas tank, and the rest of the plastics.

what started out as simple maintenence, turned out to be quite a big job.

So i got her back together last night, had some fuel issues, had to bleed the line from the tank to the petcock, and I installed the fuel lines backwards, so i switched them this morning, but she fired right up with a little choke and held idle after a few mins, So far no oil leaks, going to take her for a ride this afternoon to make sure everything is OK
cleaned up pistons

cylinder head

engine back in frame

holds idle, still need to adjust idle

I just wanted to add that I  REALLY need a garage, this shed is a pain to work in

there is a ton of room to put in larger valves in the heads.    ill bet with polished chambers, decked head, and +1mm or so valves you could get some pretty good top end power. 

this gives me ideas.