Well I got the head pulled off!!! - UPDATE

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Well I got the head pulled off!!! - UPDATE


Thank you to all the suggestions on how to get the head off of my bike. Well, this is what I figured I would find after the spark plug on that side was rusty. I'm hoping to be able to get it into the shop to have the pistons hydraulically pushed out. They recommend this technique as it doesn't damage the piston or the cylinders. The left side looks nice, but that right one is nasty.

Well I got the head pulled off!!! - UPDATE


This is what it still looks like after I cleaned it up a bit. Looks like it will be bored out to 40 over after all.
 
Re: Well I got the head pulled off!!!

Ugh, hope it works as planned but think I'd plan on new pistons, after seeing what bore looks like. I've had pistons knurled to fit in slightly over bore d/t clean up hone to get wear tapper out. Worked great even though later tear down showed a lot of the knurles rubbed off.
 
Re: Well I got the head pulled off!!!

Man that left piston top is clean.
Was that ATF and acetone that disolved the carbon?

Bob
 
Re: Well I got the head pulled off!!!

Is it just me? but what pistons are those, I thought commando's had valve pockets?
 
Re: Well I got the head pulled off!!!

Definitely new pistons and rings, THEN have the cylinders bored to fit the new slugs to spec.
 
Re: Well I got the head pulled off!!!

That was ATF that I soaked the pistons in. The left one all I did was wipe it out with a rag. I pulled the push rods out and refit the head back on and refilled both cylinders with ATF while I wait for the shop to have some time to work on it. They may not be able to look at it until the fall, but I will see what I can do until then. Still got more stuff to tear down to get it to the frame.
 
Re: Well I got the head pulled off!!!

stockie2 said:
Is it just me? but what pistons are those, I thought commando's had valve pockets?


Mine didn't have valve pockets orignally (when i got it not from factory per say). I put in some others and they did plus they were dome soo they must make all types
 
Re: Well I got the head pulled off!!!

I've read a number of tales of dropping whole engines or even whole bikes in tub of diesel or kerosene a year or more before attempting any opening up.
 
Re: Well I got the head pulled off!!!

Standard 850s don't have valve cut-outs. It's therefore most important not to just mark left and right cylinders but also front when dismantling.
 
Re: Well I got the head pulled off!!!

The numbers stamped in the top of the head are indicating that the pistons are now 0.20 over?
Or is that something else?

On another note, is the drastic difference in appearance due to one sitting on compression with valves closed and the other open to atmosphere or something else? (If you know)
Russ
 
Re: Well I got the head pulled off!!!

Why wait til Fall (autumn!!) make up a plate to bolt to the top of barrel with a hole over the middle of cylinder. Weld a nut onto bottom of plate and use a bolt to screw piston down a bit of metal plate or wood will protect piston crown. Altenatively tap hole for a grease nipple and hydraulic out with a grease gun. When piston is out if the rings are stuck in their grooves boil them in water until they pop out. Done it loads of times never failed. Good luck.
 
Re: Well I got the head pulled off!!!

A note of precaution.

By the looks off the pistons, I would say that the top end may be fresh. Old, but fresh. This may indicate a failure of some sort right after rebuild. Not knowing the history one can only assume. Due diligence may be in order to validate the true condition overall.

I am saying this so that if you go just so far and upon start up the true nature of the beast becomes known you won't be kicking yourself in the ass for not going where you had to when it was available to you. I am also not saying that you have to split the crankcase, but the timing train and related item have to be gone over.

How does the head look. The head is so critical and should be considered a hobby in itself.

A lot can be done without the big split or engine removal. You can check the cam and lifters, pull the gearbox, see if the swing arm spindle will take oil and check for free play and freedom of movement.

The lubrication system requires a level of intimacy and study to fully understand.

These bikes, simply put, are an assembly of assemblies and for ease of servicing and to save yourself the feeling of being overwhelmed, should be thought of as such.
 
Re: Well I got the head pulled off!!!

No need for any dramatics for the pistons. I pulled the head off this morning and then pushed the bike around in gear a few times and it broke free. I took the cylinders to the shop and they honed them out a bit and they are almost as good as new. I need to clean up the one piston and put the new rings on!!! I cannot believe my luck! Now to finish pulling the motor so I can send the frame out to be powder coated. Here are some before and after pictures.

These 2 are the top and bottom of the bad cylinder before it went to the shop.

Well I got the head pulled off!!! - UPDATE

Well I got the head pulled off!!! - UPDATE


This was the piston out of the bad cylinder.

Well I got the head pulled off!!! - UPDATE


And here is the cylinders after they came back from the shop.

Well I got the head pulled off!!! - UPDATE

Well I got the head pulled off!!! - UPDATE

Well I got the head pulled off!!! - UPDATE


As for the head, it seems to be in good shape, and the bike shop is going to give it a once over, and a cleaning. They will let me know if there is anything wrong with it, but from the sounds of it, it appears to be in good shape.
 
They are not pits, just a little staining I was told. I couldn't feel anything by running my finger over it.
 
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