Topic: Senior project for high school - 78 CB750K

[Restoration Fan]

Also, we worked on splitting the cases today.  We had already removed the upper bolts on the case but flipped it up on the side today so we could remove the oil pan, oil pump and all of the bolts on the lower side.  My buddy couldn't come over because of family responsibilities, so we decided to go it alone.

Two questions:
1.  The only two bolts we left in are the two large ones you can see in the photo below.  We put a ratchet on them and tried turning them, but the 14mm socket (seemed to be the one that fit them) is trying to round off the head.  Are these supposed to be removed?



2.  And this is the big one that's two parts.  The manual says to turn the case upside down so that the cylinder head is on the bottom and remove the lower half of the case that way.  But that's kind of like saying "Prepare the rocket to go to the moon.  Hit the button to make it go."  Ummm...could we get a few more details there, please?

a.  Like, how do you guys do this so that you don't damage the studs because turning it upside down means that these studs are going to be holding up the weight of the engine.
b.  It appears the PO used blue gasket sealant between the two case halves because you can see small traces of it in the seams between the two.  Is there some technique to separating the two halves?  Like do you use a razor blade to try and cut that gasket or do you just grab it and yank? 

[Restoration Fan]

I have a front rim for shipping.

tt

toyfuff,
I sent you a PM.  I'll definitely take the rim and gladly pay you for it.  Just let me know in the PM how you want me to pay.  And thank you very much for the offer.

[toytuff]

Replied.

Let me check the condition. Might be the same as yours, might be better.

tt

[Restoration Fan]

I only ever split my cases when the motor is installed on an engine stand. Never done it on a bench. 

Yeah, Logan and I were looking at it and going, "Uhhhh...do they REALLY want us to turn this thing over and have the weight of the engine resting on the studs?"

We decided to work on other stuff for the afternoon and wait until someone on the forums gave us some better suggestions than just "flip it over". 

[Old Scrambler]

Large Wooden Blocks...............several

If I'm seeing correctly..............those large bolts are the galley caps and do not have to be removed. Hint.........are you sure you removed all of the cap-bolts from the top?  If so, insert a thin pry-bar at the rear corner of the cases and tap/pry lightly. They should break lose without much effort.

After cleaning, if the case edges are not damaged, all that is needed is an evenly spread thin layer of Honda or Yama-bond. Do not use anything with the word 'silicone' in it.

[danyo]

I splited cases yesterday. After  removal of top case bolts, then turn upside down ( engine stand) , removal lower case bolts - I could hear pressure release sound (something like pssssss and I was able to pull lower case up with little wiggling. My case was never opened before so no rtv to fight. I subscribed to the thread and I'm watching your progress in hope I can use info from members. I barely have time to work on my project - 1977 cb 750k - so I didn't started my restoration thread - just following yours. Also english is my second language so it's time consuming to build a sentence for me. This forum keeps me belive that I will be able to put everything back together.  Back to my engine - looking much better inside then outside. What is your plan regarding preparation for painting cases. You going to remove old paint ( if yes -how- soda blasting?, paint stripper?) or spray over old paint after cleaning, degreasing.

[Restoration Fan]

I splited cases yesterday. After  removal of top case bolts, then turn upside down ( engine stand) , removal lower case bolts - I could hear pressure release sound (something like pssssss and I was able to pull lower case up with little wiggling. My case was never opened before so no rtv to fight. I subscribed to the thread and I'm watching your progress in hope I can use info from members. I barely have time to work on my project - 1977 cb 750k - so I didn't started my restoration thread - just following yours. Also english is my second language so it's time consuming to build a sentence for me. This forum keeps me belive that I will be able to put everything back together.  Back to my engine - looking much better inside then outside. What is your plan regarding preparation for painting cases. You going to remove old paint ( if yes -how- soda blasting?, paint stripper?) or spray over old paint after cleaning, degreasing.

We have the head and cylinders already off and have been working on cleaning those slowly but steadily.  I'm thinking about taking the cylinders to a place here in Atlanta to try their dry ice blasting on the fins.  It's the same process as soda blasting but it uses finely powdered dry ice instead of soda, so there's no soda residue left.  If that works out well, I'll take the head and the engine casing there to do the same.

Worst case, we'll use aircraft stripper on the engine case to remove old paint but we will definitely not paint over the old paint.

Here's a link to the place that does the dry ice cleaning.  I found them online so I'm going to call and ask for a quote tomorrow morning.
http://georgiadryiceblasting.com

Edited to add:  This brings up a question.  You guys who use soda blasting on your engines, do you allow them to soda blast the top of the cylinders and head to remove the old gasket material or is the aluminum material too soft for that?

[Stoli]

You'll need to prop the engine up so the studs aren't shouldering all the weight, or if you plan on replacing the studs, then remove them before you split the case.

[Restoration Fan]

Answer to your question: soda blasting is quite and will normally remove the gasket material too. As for blasting the head, I'd leave the valves in place and blast. This protects the seats while cleaning the chamber.

The only issue with soda blasting is the need to clear the residue from the oil passages. Denatured alcohol or Mineral Spirits works well for that. Or even a parts cleaner is fine.

If you are painting the cases at home, after cleaning/degreasing (whichever method you opt for) preheat the cases in the oven. 20-30 minutes on 350 is enough. This will help drive the impurities from the alloy. Then wipe down with Acetone or Dentaured Alcohol (my preference as it completely evaporates) before spraying. You'll get a better bond and the paint will flow just that little bit better.

Return to oven cure paint after no longer tacky.

Great advice, cal.  Does the oven make the house smell really bad or is it pretty much odorless when it's oven curing the paint? 

[Restoration Fan]

She's out of town until Sunday for work, so I'm hoping we can get this thing buttoned up this week and prepped for painting.  Otherwise, it'll wait until she's travelling again.  But that may well be next week.   If so, we're golden. 

[SOHC4 Cafe Racer Fan]

What's that new and interesting aftertaste to the roast?

[Stoli]

I've never noticed the smell to linger. Seems like it is always gone within an hour or two. 

[SOHC4 Cafe Racer Fan]

I'm sure you will get some residue on your food for a while -- maybe not enough to taste it, but enough to ingest it.  Think of eating baked paint! Hey, most of us lived through the 70's and 80's so this probably won't kill you!

[grcamna2]

I live alone and I've done it in my oven many times  . I open the windows while it's baking and then close them later;the smell disappears that way,especially w/ a fan in the window.

[toytuff]

I live alone and I've done it in my oven many times  . I open the windows while it's baking and then close them later;the smell disappears that way,especially w/ a fan in the window.

Remind me to "skip" dinner at your house.

 

tt

[70CB750]

I live alone and I've done it in my oven many times  . I open the windows while it's baking and then close them later;the smell disappears that way,especially w/ a fan in the window.

Remind me to "skip" dinner at your house.

 

tt

Ever observed your wife opening dishwasher - and all wooden stock parts from 1916 SMLE slide out? 

Dishwasher is excellent for removing Cosmoline.

[Restoration Fan]

Today....is a good day!!!!!
Of course, my granddad always said that any day above ground is a good day...so that should have been obvious.

But, we got the cases split.  We built a little homemade stand to hold the cases so that the studs don't get broken.



As a tip for someone else doing this, we found it much easier to get a grip on the lower case half when we stuck screwdrivers through the holes that hold the pins that go through the frame to hold the engine in the frame.


And, voila!  We are now able to get to the kickstarter spring to finally try and determine what's wrong with it.




HOWEVER, we do still have one nemesis.  This little bastage kick spindle stopper pin.  The manual says to rotate the pin to enable removal.  But I'll be doggoned if we can get the thing to move.  We tried channel locks, vice grips, needle nosed vise grips, a screw driver and pretty much anything else we could think of.  Is there some secret trick, like you have to keep your tongue in the left side of your mouth or something?

[toytuff]

Put it in the oven!

You have until Sunday. 

tt

[Restoration Fan]

Put it in the oven!

You have until Sunday. 

tt

LOL. Well played, sir.  Well played!

[danyo]

I soaked that pin in pb blaster overnight and used long nose vise grips to wiggle left and right and pulling up. I believe torch method should break loose that pin quicker

[70CB750]

Better to use vise grips to squeeze the pin than wedging screwdriver in it.   Heat would help - as the last resort - but the bond between steel and aluminum can be broken by knocking on it gently with a hammer.

[toytuff]

350 degrees for one hour or until golden brown.

 

I'm dying here....lol!

tt

[Stoli]

Just use some wire cutters like in the picture you posted. Vise grips won't work. Put something between the case and the cutters to protect the case and that will act as a fulcrum. Grasp the pin with the wire cutters and that's your lever. You will be able to rock the pin out a little at a time. Heat is good for things that are corroded in place but that pin has sit in oil it's whole life. You just need the right force to move it.

[Restoration Fan]

I have a question about something neither Logan nor I understood last night.  The kick starter gear itself.  When the engine is assembled, it connects to the oil pump gear.  Shouldn't that kick starter gear turn all the time to make that pump work?

But when we manually spin the final drive gear there (the one connected on the other side to the front sprocket), there seems to be nothing tying that gear to the kick starter gear.  Am I just misunderstanding how that works?

[Stoli]

The gear does turn all the time when the engine is running. But it does not have a direct linkage to the kickstart shaft that it is mounted on. The linkage between the kickstart shaft and that gear (presumably you have a problem with yours) will only engage when you turn the shaft by "kicking" the bike over. Sort of like pedaling a bicycle  -  the rear wheel will keep turning even after you stop pedaling.

Do you understand why the wirecutters work to remove the pin while vice grips and pliers don't? The cutting edge of the wire cutters dig into the sides of the pin allowing enough of a grip to "pull" it out of the hole. Anything else you use will tend to slide on the pin because it can't get enough traction. You will wind up with small dents in the pin where the cutters dug in but the pin can be reused (although it should be pretty easy to find a replacement).