Hey folks!
So I'm having some difficulties finishing my valve shim adjustment. I have a whole long narrative which I can lay out, but I'll spare you all that for a moment and just ask a few questions for starters.
1) Are there any theoretical consequences to cranking the engine over (with a wrench on the crank, of course) while some of the shims are out of the tappets?
2) My RT exhaust tappet won't rotate freely anymore, and comes up higher than normal without a shim and when the cams are aligned correctly for adjusting that particular valve. Any thoughts?
3) And finally, any reason why I can't rotate the crank even if all shims are seated correctly and the bike is in neutral, etc.? It cranks in reverse (only went an inch or so bc I'm not sure what can happen if I go too far backwards - just mentioning it so you know it's free up until a certain point).
Like I said, I can lay out the full story if necessary, but any thoughts on these questions would be greatly appreciated.
Thanks!
Do you have the plugs out?
Try turning it over by putting it in 6th gear and pushing the bike or turning the back wheel by hand, should turn over easily without the plugs.
Sorry, forgot to specify - plugs are out and it was turning over at one point before.
Possibly your shims are too thick and hence the cams have no chance of opening the valves?
What does the top end look like and what is it doing when you try to manually turn the motor? (You should only go clockwise).
Could something have fallen down into the motor and is locking up the cam chain?
If memory serves me correct I wouldnt crank it over with the shims out the buckets, they can damage the cam lobe.
A little more background. The shim was actually .05mm thinner than the previous one (which still had .04mm of clearance, so it wasn't a problem before. Cam lobes look to be okay but one may be slightly scuffed. And I had a rag in the galley and I'm not missing shims/tools so I don't believe anything could've fallen down into the motor. When I put the new shim in, it was hard to turn but eventually went around one full cycle before locking up again at the same spot (the position for adjusting RT exhaust and LT and RT intakes). Just feels like it's at a hard stop.
So now the rest of the story. Besides previously turning it one revolution without all the shims in, I initially had a hard time getting the shim out. The official valve shim tool was giving me trouble (I now realize it doesn't orient perfectly perpendicular to the camshaft when you put it in, but rather you have to angle it in slight to get it to actually stay on and depress the tappet as you rotate it down).
So I decided to try the "screwdriver method." This resulted in me scuffiing the inside of the block just to the left edge of the RT exhaust tappet. Basically scraped some paint off and exposed some aluminum from the block, producing a few shavings (which do not seem large/strong enough to grind anything to a halt). The tappet still rotated freely in there so I cleaned it out as best as possible and got the new shim in.
Now, I'm stuck on that position, the shim has zero clearance (even though thinner than previous (2-60 vs 2-65) and the tappet won't rotate. What's more, the tappet seems a little higher up, closer to the cam than it did before.
I think I maybe upset something below the tappet (the piece in between it and the top spring retainer perhaps?). Or maybe something at the valve/piston? I have no idea.
Hope that's clear enough and looking forward to the replies. Thanks guys.
depending on miles and how hard the service was. could be a number of things. your saying the shim bucket sits higher then normal, and is tight even with a thinner shim, try a thinner shim then that. its possible a burr might be giving the bucket a headache but i can think of things far worse to be causing your problem. the part that worries me is not being able to turn the crank very far. hope you didnt bend/break a valve or have a keeper give up.
Quote from: slipperymongoose on December 07, 2013, 05:20:11 PM
If memory serves me correct I wouldnt crank it over with the shims out the buckets, they can damage the cam lobe.
That will scratch up the cam lobe a bit ... but I rode one with a nice crow's foot look scratch in mine for 40K miles ... It takes oil and holds oil and self restricts its own wear ...
Cool.
Buddha.
Are you sure you haven't broken a valve off the stem? That could explain the bucket sitting too high and the inability to crank over.
Broken valve would cause lockup of crank at position you describe with right piston coming up to top. Have you looked into the plug hole to see if you can see it, I broke my right exhaust valve one freezing cold morning when a too tight bucket held it open and could see it thru the plug hole. You may have dislodged chips that held the bucket down long enough to go bang, broken valve would release bucket upwards..
Metal shavings locking the bucket in the up position?
You mentioned metal shavings and that the bucket now does not turn freely.
As always, thanks for the thoughtful replies, guys.
So I had a look in the right plug hole and I saw what looks like the valve, dropped all the way down, just sitting on the piston. I could see the valve stem and everything. That means the valve or something in between it and the tappet up top broke and the valve just dropped down, right?
Which means ultimately the head has to come off?
My guess in this case and it's only a guess is that one of those chips/shavings got wedged in between the tappet and it's bore and held the valve open just long enough to cause an internal collision. At least you know what needs to be done now; off with the head!
By the way, there is nothing between the valve and the tappet unless a keeper somehow got loose in there.
Yep, thanks Jack.
It'll be a couple days before I can pull the head. I'll be watching videos and reading the manual in the meantime. I'm definitely in over my head now (if I wasn't already!). I don't imagine the fix will be really simple and I certainly don't have anything beyond the standard hand tools. From reading other posts, it seems the thing to do would be to just get the head off and take it to a mechanic...
Quote from: younastytwin on December 08, 2013, 11:31:00 AM
Yep, thanks Jack.
It'll be a couple days before I can pull the head. I'll be watching videos and reading the manual in the meantime. I'm definitely in over my head now (if I wasn't already!). I don't imagine the fix will be really simple and I certainly don't have anything beyond the standard hand tools. From reading other posts, it seems the thing to do would be to just get the head off and take it to a mechanic...
What is left may be salvageable. Just leave everything as-is and take it to a machine shop. Trust me.
(from a guy who is way in over his head time and money-wise and wishes he had just taken the original head to a machine shop)
Pictures of inside of bucket (tappet) and top of valve/spring assembly:
(http://img.photobucket.com/albums/v443/jcp8832/bucket_valve.jpg)
And my broken exhaust valve:
(http://img.photobucket.com/albums/v443/jcp8832/valve1.jpg)
Actually it can be better to have a broken valve than a bent one if you have a tight bucket, the bucket can be very difficult to get out. I was able to reach up thru the valve guide from inside of head to drive out the remaining piece of valve stem and the too tight bucket with a long punch and hammer.
Thanks again, Jack and company. I can see a lot of the stem through the plughole so either I broker mine higher up on the stem or something else came loose/broke. I'm going to pull the head tomorrow night so we'll see.
One last question - with 12k miles, is it likely that I'll be able to re-use the head gasket and O-rings, or is that asking for trouble?
If you re-use them, you're not asking for trouble. You are DEMANDING trouble.
I think if you have to ask if it is OK to re-use gaskets, you should be using new. Gaskets are cheap compared to having to take it all apart again because the re-used gasket didn't seal.
Only re-use if u absolutely have-to.
You don't re-use head gaskets. Period.
Except...yes, there's always an exception....the Gipsy Major engine in my 1940 Tiger Moth had bronze heads and copper head gaskets. You could anneal the copper gaskets and re-use them.
(http://www.airplane-pictures.net/images/uploaded-images/2013-6/29/300301m.jpg)
Kudos on the kite!! :thumb:
Fair enough. That was my initial instinct but just wanted to confirm since head gaskets alone are $50! Thanks all.
Quote from: younastytwin on December 12, 2013, 09:32:46 AM
Fair enough. That was my initial instinct but just wanted to confirm since head gaskets alone are $50! Thanks all.
Cereal box card board and some copper spray paint?
Don't you mean cereal box cardboard and toothpaste?
Quote from: the mole on December 13, 2013, 01:15:34 AM
Don't you mean cereal box cardboard and toothpaste?
I thought tooth paste was for teeth?
Quote from: younastytwin on December 12, 2013, 09:32:46 AM
Fair enough. That was my initial instinct but just wanted to confirm since head gaskets alone are $50! Thanks all.
Don't go cheap. You'll redo it in no time if it even works. Buy the right thing unless you don't depend on your gs for reliable transportation.
the more the miles the less the O=rings are going to be forgiving for reuse. the head gasket, unless damaged in removal (creased,kinked, torn, or otherwise distorted) can generaly be reused once completely cleaned up of factory coating and degreased then given a couple coats on both sides of spray copper gasket. ive reused headgaskets several times in this manor. the headgasket doesnt hold back oil pressure or a cooling system that can become pressurized when hot. anywhere there is paper gaskets almost always need replaceing. rubber O-rings, copper crush washers need to be inspected and judged carefully before reuse.
truth be told, you could cut up a stop sign scrape it clean, degrease it and spray it with that copper sealant and use it as a headgasket for the GS engine. compression would be alittle low because its so thick, but it would work and hold up fine.
Had to leave the bike alone for a few weeks over the holidays but I'm back in there and determined to get this thing straightened out.
1) I now have a new head gasket, o-rings and cam chain tensioner gasket. Do I need new copper washers for the cylinder head too?
2) I've got all 8 nuts off the cylinder head (washers appear to be stuck on - I guess they're "crushed" on?) and removed the little bolt on the outside of the head up front. BUT I cannot get the head off. I've tapped the back side with a rubber mallet, tapped the front side with a rubber mallet and piece of wood. I've tried to carefully pry using a wide blade screwdriver on the back side just under the intake ports. I've gone around with a hammer and thin-blade screwdriver at the seam to try to loosen it that way. And no movement that I can see at all. All I seem to be doing is taking off paint and risking cracking a fin.
Any ideas/suggestions?
Thanks again, guys.
The copper washers are crush washers. They are cheap and yes you should replace them.
You have to pry from various points to get it off. Pry a little at a time all the way around. Eventually it will separate.
The cams must be loose or off because the cam chain will hold it on.
Be careful you do not pull the cylinders off with the head. (been there, done that...)
Insure you are prying apart where they join.
Thanks Adidasguy.
Finally figured out that it was those crush washers that were holding it in place (are everybody else's washers just loose on there after you remove the cylinder head nuts?). Once I unstuck those from their seats/studs, I managed to get the thing loose.
BUT NOT BEFORE cracking the seal of the cylinder gasket on the front side. Little bit of oil bleeding out now. It didn't totally come off the crankcase though.
Can somebody confirm/deny that I now have to pull the cylinder off as well and replace that gasket (as opposed to just putting the repaired head back on and torqueing the whole thing down.
Quote from: younastytwin on January 10, 2014, 05:46:33 PMCan somebody confirm/deny that I now have to pull the cylinder off as well and replace that gasket (as opposed to just putting the repaired head back on and torqueing the whole thing down.
Confirmed. Lots of sand and crap gets into the front center stud channels which are exposed at the front. When you lift the cylinder it's very likely it gets between the cylinders/block or in other places it shouldn't be.
Often they come a little loose. It can be expected since you've removed the 8 nuts holding that thing on there.
So far, I just leave it and it torques back down just fine. Never had a leak.
If I changed cylinders or had to completely remove them, I'd put a new one on.
Quote from: Badot on January 10, 2014, 06:07:16 PM
Quote from: younastytwin on January 10, 2014, 05:46:33 PMCan somebody confirm/deny that I now have to pull the cylinder off as well and replace that gasket (as opposed to just putting the repaired head back on and torqueing the whole thing down.
Confirmed. Lots of sand and crap gets into the front center stud channels which are exposed at the front. When you lift the cylinder it's very likely it gets between the cylinders/block or in other places it shouldn't be.
Really good point there, Badot. It's not a bad idea to make a decent hose-out of this front area....around the bottom front of the cylinder-block, and around the cross-engine installation stud.....a regular thing....like when the bike gets an overall wash. It's somewhat surprising the amount of sandy crap that builds up there.
I just found this thread.
Do you want the workshop manual?I downloaded mine as a PDF file off the internerd somewhere.It shouldnt be hard to find -or i can send you a copy
You know,i've been thinking.Could it be that the valve has simply lost it's collets (while you were playing about above them) and dropped onto the piston with no damage at all?
I guess you'll find out soon!
Oh and BTW.If the valve is intact ,you'll want to test to see if it's bent.There is a simple and easy way to leak test them which will show if they're bent.Just ask me about it if it gets to that
Thanks Ron (and company). I'm using a Clymer manual paired with the BaltimoreGS rebuild videos. And yeah, finally got the head off, and unfortunately, the cylinder as well.
Valve was broke so I'm outsourcing that portion of the repair to my local mechanic. I've ordered a new cylinder gasket because the cylinder came off and the mating surfaces got some road debris all over them as described by folks above.
I've tried to clean both the crankcase and cylinder mating surfaces as best as I could (and praying nothing too serious fell down in the case itself - although can I assume that it'll get caught up in the oil filter as long as it's not too big?).
Next steps are to clean the sooty piston domes as described in the manual (anybody know what kind of "soft scraper" they might be referring to? Just a soft bristle brush or something?), replace the cylinder gasket when it arrives, get the cylinder back on, and then hope my mechanic's done fixing that valve in the head. Then get it all back together and pray to any and all gods that it runs ok!
Alright, time for an update. I got the cylinder jug back on after replacing the gasket and cleaning the piston domes. My broken valve was repaired and I got the head back on.
I had a little trouble getting the cams back on, especially the exhaust. Every time I began tightening the caps down the chain would jump a link on the sprocket and screw up my alignment by one pin. I'm guessing this was because the cam lobe of the left exhaust valve was having to push the valve shim/bucket down as I tightened it down onto the head. I finally got it on byalternating tightening the left and right (A and B) cam caps more frequently. I just barely brought it down on each side so it seated evenly.
The cams look like they're in there okay and the motor turns over but I wonder if there's not still some sideways tension on the chain over the exhaust cam sprocket. And I wonder if this has something to do with the tach gear drive. Is there anything that needs to be done to ensure the gear on the camshaft properly aligns and meshes with tachometer drive gear below it? Or does it automatically line up when you tighten the cam down?
Thanks again!
Tach gear is automatic so no worries there. It will line up properly either right away or when the cam is wiggled a little.
Insure you did put in the washers on the left end of the cams.
When tightening cams and you encounter it pressing on the valve, rotate the motor clockwise a little. There is a position where no valves are pressed on and you can tighten down all cam journals.
Remember the front cam guide (we left it out once - oops! Might be why the timing was off 1 tooth after we put it back in.)
We have a second set of hands hold the cam chain tensioner screwed in so there is no tension as we put the cams in and tighten things down.
As mentioned, if engine rotated so no valves are being pressed you can tighten down everything and even release the cam chain tensioner. The chain will hold the cams down. After journals tightened, rotate engine more to verify your timing.
Also insure you havethe cams in the right way. The right ends will have that notch which you use as an alignment guide. Other than the intake being backwards, I can't think of what would cause sideways tension on the chain (other than the end washers being in wrong).
Awesome, thanks Adidas. Ok, good to know on the tach gear. Looks like it's spinning in there so I'm calling it fine. And yes, the washers on the left of the cam are on there and spin freely, so I think I'm also good there. Front cam chain guide is in there as well. Like I said, everything lines up properly and spins freely so I think I might be being a bit paranoid.
One other question - does the little cap in the back of the cam chain tensioner (the one that covers the hole with the screw inside) need to be on there absolutely. As in, does it keep it oil from coming out or anything? I don't think oil goes in there but just wanted to check since I tore the thing in two getting it out of there.
Awesome, thanks Adidas. Ok, good to know on the tach gear. Looks like it's spinning in there so I'm calling it fine. And yes, the washers on the left of the cam are on there and spin freely, so I think I'm also good there. Front cam chain guide is in there as well. Like I said, everything lines up properly and spins freely so I think I might be being a bit paranoid.
One other question - does the little cap in the back of the cam chain tensioner (the one that covers the hole with the screw inside) need to be on there absolutely. As in, does it keep it oil from coming out or anything? I don't think oil goes in there but just wanted to check since I tore the thing in two getting it out of there.
The cap keeps it clean in there so it doesn't get gunk in there that would make it get stuck.
Some bikes don't have it and no leaks from there.