catastrophic headgasket failure with pics.

[Brian902]

I heated my cylinders in the Barbecue to 200 degrees and came out to find the cylinder had slid down the sleeves.

After a day of scratching my head, I reheated the cylinders to 200 degrees, on the Barbie,
took the cylinder back into the work bench, dropped each sleeve back in and job done.

In your case I would get the machine shop to plane the head until one even surface with the minimum amount of planing.

 

[malloym]

When you bore jugs its because you are putting much larger pistons in stock cylinders. If you look at a stock set of jugs there is more material between rim and stud hole. His are bored all the way out to the holes. NOTHING WRONG with doing it this way but tolerance is the key and maybe when they put them in they were perfect and 300 miles of heat changed it. There also can be a possibility that they cracked inside under the heat because not enough material. Seen that before. That's why they make new kits with bigger jugs. I never done one that big on a XS650 but I have done the kits and much bigger material. Again take into account both may have not screwed up your 30 year old jugs just may have quit. Good thing is sleeves still useable and you only took out a gasket motors blowup and rods come out the bottom when this gets close to crank.

these are NOT stock jugs. I purchased LA cylinder big bore jugs and had the machine shop install them. i can't remember if they were flush or not from the begining

 

[5twins]

The "jugs" are the cylinders. I think what you meant to say is these are not stock sleeves but rather LA Cylinder big bore sleeves.

 

[xjwmx]

Thanks, DADDYG. Great info as always. Somehow I missed reading they were aftermarket and oversize! No eye for detail...

 

[member3480]

I got what he meant. I use the term jugs as the other part SLEEVE is the parts you bought. I have seen that kit. You can't mill it down either because the piston is going to travel the same distance weather the sleeve is down or up. If you have to take 60,000 or more off them you just ate up all the difference between the top of the piston and the valves.
What I would do is take them back to machine shop let them take out the sleeve which is lower INSPECT for damage if none press them back in BUT !!!!! use some kind of sealant that will bond the metal to metal and heat not affect it if that's your only option. Me I would buy another set of jugs and put the sleeves in them . May happen again when motor gets hot if these jugs are damaged. Sorry I am only telling you from blowing up many race motors because I tried something that didn't work.

 

[xjwmx]

Maybe the jugs fit the sleeves and the shop just pressed the sleeves in too far. That's possible, since the op doesn't know how they were when he first got them back. Easy fix if that's the case. If it's just that it would be a shame to get new jugs.

 

[650Skull]

after 300 miles on my new engine build the headgasket blew. L.A cylinder sleeves installed by the same machine shop I always use. I'm running wiesco 80mm pistons. you can see near all the stud holes the gasket was leaking. these bigger sleeves go right to the edge of the locating dowels. I also noted the sleeve is just a hair lower than the jug. any ideas as to the cause of failure? I also want to add that after 100 miles the left inner stud kept coming loose, even after a proper retorque. I was getting compression out of the hole. another member on this site had the exact same problem but has failed to respond to me.

if you guys need any other photos or better pics just let me know.

also when the bike was running, everything seemed good, nice idle, plugs had a nice coffee color, good power, etc.. then the gasket let loose.

The sleves seem to be the same as 270YAM's, 91mm OD. If they are 270YAm explains, (with pics), the problems with using those sleeves in original 650 Barrels in post 5 and 6 HERE. Seems the bottom case has to be bored in line with the barrels

 

[650performance]

I agree about milling the head surface to obtain a truly flat surface. You can then buy a copper head gasket that is slightly thicker than the stock (measure when compressed) gasket in an amount equal to what has been shaved off.
The copper gaskets work perfectly with high compressions even when some minor surface irregularities exist. Plus, they can be reused. Michael Morse at 650 Central has some. Check with him re the available thicknesses.

 

[270YAM]

I had the same thing happen on my 850. Well similar anyway, I was running a copper gasket so it leaked instead of blew out. It leaked back down the stud holes and into the crankcase and was throwing oil out the breather like crazy!
The machinist bored out the jugs (the aluminum bit with the fins) heated it up and dropped the sleeves in, leaving the sleeves slightly higher than the deck. Once it had cooled he machined the top flat- sleeves not sunken too far in or protruding, all dead flat ready for assembly.
The problem was he failed to keep downward pressure on the sleeves while they were cooling, and the aluminium block shrunk in height at a greater rate to the iron sleeves. This formed a gap underneath the flange at the top of the sleeve (the gap of course cannot be seen) as soon as the block gets up to temp the sleeves slide down and fill that gap, leaving insufficient crush on the head gasket causing it to leak or in your case, blow.

Sounds like it no big deal at all, just take a skim off the top and level it all up again.
A thicker base gasket is also an option for compensating the loss of deck height, or you can measure up and make sure it all fits and just run with standard gaskets and a bit of extra compression.

If using copper gaskets I would recommend a coat of Hylomar spray on the gasket for better oil sealing, because the copper is not as spongy as a composite gasket

 

[malloym]

I want to thank everyone for the feedback and insight. I'm going to call the machine shop tomorrow and probably take it back to them. 650 central offers a thicker overbore headgasket which might help. i'll keep everyone posted.

 

[270YAM]

The sleves seem to be the same as 270YAM's, 91mm OD. If they are 270YAm explains, (with pics), the problems with using those sleeves in original 650 Barrels in post 5 and 6 HERE. Seems the bottom case has to be bored in line with the barrels

If they are 80mm LA Sleeves the OD will be smaller than 91mm, and the lower end should drop straight into the crankcases without any machining.
I am pretty sure 750 sleeves don't break throughout the wall of the cylinder casting when installed, but that can also depend on the original casting as they can vary a fair bit

 

[TwoManyXS1Bs]

When we resleeved cylinder blocks, we would place a heavy steel plate atop the assembly during cooling, to prevent sleeve upward creep. May want your machine shop to reheat the cylinder block and reseat the sleeves, with something on top of the sleeves only, to guarantee that the flanges are fully seated.

 

[malloym]

If they are 80mm LA Sleeves the OD will be smaller than 91mm, and the lower end should drop straight into the crankcases without any machining.
I am pretty sure 750 sleeves don't break throughout the wall of the cylinder casting when installed, but that can also depend on the original casting as they can vary a fair bit

you are correct. these are the 80mm LA sleeves

 

[member3480]

Your making the right decision to take them back they can see if they made a mistake or it can be corrected easy. I know if they were a good machine shop they would have never let you take them if one is lower than the other. I think when you installed them they were even and the heat made the change . Just make sure if they take anything off ask how much because you are going to have to make that up with a larger gasket or you will have your next problem.
Good luck hope it works out easy for you.

 

[malloym]

UPDATE!!! 2/10/14

So I took the jug back to the machine shop and they have to remove .006 to get it true again. they were super cool and did it that same day. I reassembled the engine and it starts right up. I took it for a spin around the block and it feels very strong. I do have some concerns::

I'm getting a light popping from the right exhaust during idle. any ideas? I did install a fresh set of plugs. I didn't recheck my valve adjustment after reassembly ( well not yet any way)

how many times are you guys re-torqueing the head after a new build??

is it possible for the cylinders to drop again??

 

[DIRTY DOG]

I'd check the valve adj. do a plug check make sure it's not running lean,if all is ok then ride it a little to brake it in a little then rechek cam chain adj valve adj carb adj. if all is ok ride the hell out of it.

 

[cra-z1]

Glad you goy it sorted

 

[XSLeo]

I do the first torque when I assemble the engine, let it set overnight, torque.
Install in bike, Start it up, let it get warm, shut it down. Let set overnight, torque.
Start it up ride it about 50 miles. Drain oil check the oil and filters for debris. Torque.
Run it 100 miles, drain oil. Check oil and filters for debris. Torque.
I stop torquing when I can't add more torque. By that I mean when I check the torque the bolt wont turn at what the torque wrench is set at.
It may take only the two first times to hold torque or it may take more.
Leo