cylinder head problem

[draku]

hi
I need help.
I have a yamaha fj1200 1991 with 90,000 kilometers
I have to check piston ring, because it seems that has oil consumption.
problem is that I can not remove the engine cylinder head.
I removed the cam shafts, the 4 nuts in the front and rear cylinders and the 12 large nuts from cylinder head studs.
cylinder head seems glued to the cylinder. in fact, side from cylinders 1 and 2 was detached, but from the cylinders 3 and 4 seems stuck.
I tried all the methods that I could think of to remove a cylinder head without deteriorating.
Does anyone have any ideas?
thanks

[fj1289]

Spray everything with PB Blaster and let it soak (even the head gasket area).  Repeat a couple of times a day.  Rap on the head with a RUBBER mallet.  Move, wiggle, etc as best as you can.  It will EVENTUALLY give up and come loose.  DO NOT pry it apart!  Some of the cylinder studs are notorious for building up "crud" and corrosion that seems to fuse them to the cylinder and to a lesser degree the head too. 

Good luck!  And have patience!

[VMS]

You've got everything apart. As stated, just work it over lightly. Yamaha had an insulation on the inboard head studs that deteriorated into a super glue like substance over time. Make sure when you go back together to use new studs, I'd recommend the APE ones, but I AM a little biased. 

Good luck and be patient

[Kopfjaeger]

used to use this stuff called "yield" comes in a gold can is like wd-40 on major major steroids... used to use it to remove rusted bolts and gaskets/flanges off pumps and valves ( industrial power plant type stuff)

[draku]

thanks all for advice
so, the answer is: some chemical stuff and patience 

I must try it

[fj1289]

Good luck!  And let us know what works for you - most of my big difficulties have been cylinder removal - the head generally goes a bit easier (but still doesn't just "pop" off!).  Once you get it to "wiggle" (which you've already done) - you've gotten through the tough part - the rest will loosen up eventually. 

Chris

[andyb]

+1

They stick on pretty hard at times.  A big rubber deadblow hammer is your friend.  And a lot of patience.  And a couple beers.


Of course you could go the alternate route, which is to let a 5 year old "play" with it.  They'll undoubtedly strip the motor down to bare components in no time, just tell them that they're not supposed to!  (At least this is what my parents always said the fastest way to take stuff apart was)...

[draku]

....  Once you get it to "wiggle" (which you've already done) ...

Chris

unfortunately, not yet....
I will try hard...

@andyb
you are right, kids are the best "mechanic"  ever (just one way...)   

[draku]

finally, victory is mine 
problem was that plastic protection over the cylinder studs and LOT of rust...
the inside image its bad ... lot of black deposit on the top of the pistons and on the valves....
that mean oil consumption....
I checked one piston ring and end gap is 0,53 mm.... that mean end of life...must change it (all of them)....

[VMS]

What do you have in there for pistons? I can probably help you out on the rings if you go that route...or maybe its time for a Wiseco big bore kit!

[draku]

here are some pictures

engine


piston (not a good picture)


cylinder head (I put some gasoline to check for leaking...)


cylinder block with 2 piston ring inside (you can see end gap, it is big)

[LA Mike]

cylinder head (I put some gasoline to check for leaking...)


I found that the one of the best ways to check how your head(valves) are sealing is to pour some mineral spirits in the intake & exhaust ports and look to see if it get past the valves and if so how fast.

Mike

[andyb]

Looks like a good cleaning and the usual rebuilding work will do you a world of good there sir!  Keep us posted~

[draku]

even so, I found leak on 2 cylinders
another problem, black paint on the cylinders and cylinder head fins look like it was "boiling". bubbles appears, maybe because of high heat when engine was running...
do not know how to clean .....

[SlowOldGuy]

I wouldn't be too freaked out about the ring gap.  It's best if the gap is a little too large rather than too small.  That's why the ring gaps are "clocked" when the pistons are installed.  When you get the new rings, I'd stay to the larger side of the gap tolerance.

As for the flaking paint on the head.  There are paint strippers you can use.  I got a lot of mine off just blowing compresed air on it.  You could also cut up a sanding sponge to get between the fins.

DavidR.