Topic: Marissa's 1972 CB500

[MauiK3]

Marissa
I am working on my K3 750 cases right now. I cleaned with simple green, wire brush on a dremel, etc. then I carefully washed with brake clean and acetone. I rigged a bag under it to control the runoff. I will be using POR15 aluminum for mine. Duplicolor aluminum is also good, as is VHT.
POR 15 is available at auto refinishing stores.
Steve

[DaveBarbier]

I agree to replace only the broken stud. Perfectly fine to use the existing ones.

If you want to spend more money but have the motor better than new, you'll have to disassemble everything, but send to Nils (Noblehops) and have him vapor blast it.

http://forums.sohc4.net/index.php?topic=164058.0

Finish ends up looking incredible and you can leave it bare. Heck, paint would make it look worse.

If you were getting low compression it could have just been from the bike sitting and the rings being a little stick/rusted. Normally in that case compression comes back up after putting miles on it.


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[Lostboy Steve]

I agree to replace only the broken stud. Perfectly fine to use the existing ones.

Personnaly, 1 stud breaking is often an indication that more will too. The motor is apart now, remove all of them, chase the threads, install new studs, and never look back.

If you want to spend more money but have the motor better than new, you'll have to disassemble everything, but send to Nils (Noblehops) and have him vapor blast it.

http://forums.sohc4.net/index.php?topic=164058.0

Finish ends up looking incredible and you can leave it bare. Heck, paint would make it look worse.

Dave is 100%. Whomever declared powder coat is a problem on these engines is 100% incorrect. Perfectly safe, very common. Vapor blasting is an excellent finish, but will require some maintenance to keep it. Else, you can Vapor Blast then clear coat the motor afterwards to protect it. Aluminum oxidizes instantly and perpetually.

If you were getting low compression it could have just been from the bike sitting and the rings being a little stick/rusted. Normally in that case compression comes back up after putting miles on it.

I agree with Dave 100%. Compression is at best an "indication" not a determination. With new valve seals being installed, it would behove you to have the seats lapped and the guides inspected for tolerances.

I didn't declare it was a problem, but the jury is still out for me on mine. Not the cases but the cylinders. I have noticed a lot of Harley's leave their cylinders and head bare but do the case. My buell was like that too.

Anyway, you're still the authority on small block hondas to me Cal. If you say it's ok, I feel better about it.


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[DaveBarbier]

Pipe is colder than the exhaust gas, therefore the heat moves toward the surface, heating it. That's why you burn your fingers; they're colder than the pipe 

So what you're saying is if you don't want to get burned by the pipes, grab a handful of coals off the grill first, then touch the pipes. Got it.

[RAFster122s]

Do you like your eggs poached or fried Cal?

[DaveBarbier]

Not exactly. But, Dave, I'd like you to try immersing your hands in water, then bring it to a roiling boil (keeping your hands immersed) then grab the exhaust. My thesis is you'll be fine since your skin will have been brought up to temperature by the boiling water.

If it doesn't work out, at least you have a good start on veal stock for supper 

"This veal soup is great, there's more fingernails than I'm used to but it's still nice."

[PeWe]

Also, do you guys recommend replacing all of the head studs instead of just R&Ring that broken one? I'm in the mindset of "Already spent too much, might as well take extra time and money to make sure it's done right"
and don't want to skip any parts I might unintentionally.

Which also leads me to the question of: what do you guys recommend to do when the original paint on the engine is dirty and in rough shape, and every place I've talked to does not recommend to powder coat it because of the heat soaking issues? Do most of you just use as spray can engine enamel? Do you guys leave it bare? I've tried aircraft remover, the orange gel paint stripper, paint thinner, sanding, soaking it for days and it doesn't do a bit of removal on the paint. Is it worth it just to get it hot tanked and leave it bare?

Thanks in advance.

Hi Marissa, I hope you do not mind details about CB750. I guess this cover all bikes.

If you can determine why the stud broke, replace the broken one only. (If you can find one). All if all look bad. The heavy duty studs are rather brittle when over tighten them. I broke an APE cyl stud due to a bad torque wrench. Honda studs are more flexible. The reason to use APE or Kibblewhite studs is the less flexibility. Max torque 22.5 ft lbs, I do  just under it 20.65 ft lbs (28Nm as I did with Honda std)

Rattle can motor paint worked fine for me. I did my CB750 with Motip (color alumin) which is rather durable. Fuel from carbs when changing jets did not ruin the paint. Easy to add some additional spray when it has got some scratches. It look more std than the 2k painted CB750 cases I have seen. Those have thick layer of 2k paint, Mercedes type. Look like engine has been dipped into it. Rattle can paint I use look closer to Honda OEM with all casting marks visible.

I sprayed cyl and head with it later on. My last cylinder is not sprayed since it has nice fresh glass beaded surface. I believe that thick layer of paint can cause higher temp in a hot climate. Hondaman has mentioned that in an old thread.

I have 3 cans more. I'll use same paint on my next project, CB750 K2. I need to remove old protective black paint first.

I washed the cases with naphta first. Then dish washer powder for dishwasher machines in a deep stainless sink with hot water. Dipped the entire case and brushed it. Dried and cleaned with acetone before some additional quick sanding with a paper. Wiped with acetone cloths again. Some axes were still in engine. Last time with most of the gearbox still in. I sprayed the steel quickly with WD40 to protect against flash rust.
Sprayed and let it dry

[SOHC4 Cafe Racer Fan]

That's a great example of how good the spray cans can deliver a nice finish.  Ideally, you should Harden the paint by "baking" it in an oven, but that's not the healthiest thing if you cook food in the oven.  You can also treat it by lining a cardboard box in aluminum foil and using a heat gun to heat up the box.  If you can't do either of these methods, the paint will harden after a few heat cycles running the bike, but until then it will be easier to damage.

Powdercoat is great, too, but requires very extensive cleaning after coating to make sure all of the oil passageways are free from blasting media.  You cannot be too cautious. People have washed their engine parts, blown water and then air through the passages and then even still found grit.

[PeWe]

Paint got time to harden since I painted in July 2012, assembled the engine several months later.
Here a photo of how the case looked before repaint. Whats left of Honda's paint. I did not paint the cases in the 80's despite I pulled engine several times that decade. I think the paint left mostly when sitting in a barn for 19 years.

Good thing with the way I did it is that some axes can be left in cases when washing it. If beading the surfaces all holes must be plugged and no gearbox or other stuff still mounted.  Save some $$ too. Hard corrosion can be brushed off.

I used Caustic soda to clean my hubs and valve cover.
It loves aluminum oxide! Bucket with a few liter of rather strong solution, 2 dl caustic soda in 3 L if I remember correctly. Part in bucket (outside for fresh air and not gas people!) use a dish washer brush and work the solution all over the surface. It react hard so use glasses and long sleeve rubber gloves. The corrosion will turn to black, let it work for a few minutes. Not too long, check after 2 minutes. Leaving it for hours can make the part to dissolve completely I have heard stories about missing heads and cases only steel thread parts left

Rinse with water and remove the blackened corrodes surfaces with steel wool. The surface will turn to a nice old aluminum grey that can be polished further. The heavy alu corrosion disappear very quick and easy.

Photos to show and encourage others.
Note! covers only cleaned with caustic soda and water, finally steel wool. Not sanded at all. The sanding tool on phote for something else.

[Marissa]

PeWe,

Thanks for the examples and the photos of what you did to your 750. Those photos have helped me determine that I think it's best if I just go with a VHT spray engine paint. I've actually used VHT bright aluminum paint on my valve covers for my 300zx and it came out well. I think it will be better for now anyways since I need to save a bit of money on this project.

Still waiting on the top end to come back from the shop. I've been working on polishing a lot of the shinier bits on the bike and trying to restore them to fill up my time without spending more money. But of course it led to me buying a stainless steel Allen bolt kit  hoping to update the thread with some real progress next time.

[Davez134]

I used VHT engine enamel on my 750, and it has held up great so far. I used the wrinkle black and cast aluminum, I don't see a chip on it yet. I might be stating the obvious here, but prep/clean, prep/clean, then do it again before applying the paint. (I also used the VHT primer on the bare metal first) and make sure to heat/cure it before any contact with gas or oil.

[PeWe]

This forum have given me a lot of good inspiration when restoring my bike. All very interesting threads with photos and all professionals knowing everything and more about these old CB's. My project went to another restore and a third later on, same bike within 4 years. Plenty of new parts and more power from the engine. I gave up the economical sense since I see no other bike I want. A nice semi controlled madness. I think it's called passion! It could have been a woman I have lived with for long time too, now a bike that has never turned me down

This thread make me eager to start my K2 project. The cases need new paint looking great again! The good powder painted frame to be welded for a frame kit since someone have cut it.

[SOHC4 Cafe Racer Fan]

My VHT engines:

imagejpg10_zpsf38e82ee by Donald Leonhardt, on Flickr

image_zpscdxixbph by Donald Leonhardt, on Flickr

[Marissa]

Finally got the top end back from the shop, no issues were found in it! So I've been reassembling the engine piece by piece now that I'm back in school. I was able to use electrolysis to remove paint from the cylinder jug; it worked okay. I still have yet to find anything to strip the finish off the engine well- I will probably invest in a media blasting tank at some point in time and use that. I painted everything with VHT flat aluminum so far and it's looking pretty good, I can't wait to install everything else on the engine so it'll have more contrast. Right now I'm waiting on sealing rubbers and piston rings before I can go further.

One issue I did find however is the clutch cover and gasket... Wish I took a picture of it but regardless, I'm hoping someone else encountered this issue and can explain what is wrong. Inside the clutch cover, the kickstart mechanism is spring loaded, and the end of the spring (on the left) sits behind the gasket between the mating surface of the cover, the gasket, and the rest of the transmission. I'm assuming this has to be here, but with the new gasket and allen bolts I'm using, it's apparent that the cover can't sit flush, and will leak out the bottom right beneath where the dip stick sits. I know this could not seat fully flush beforehand because there is no opening for the end of the spring to sit even with the rest of the surface, and I replaced the Allen bolts with the original bolts to see if it made a difference but it still leaks. Not sure what else to try, anyone have any advice?

[SOHC4 Cafe Racer Fan]

One very effective method of cleaning engine parts is vapor blasting.  Check out www.restocycle.com  It is run by Nils Menten here on the forum (who is also an Ikon suspension dealer).  Vapor blasting leaves a like new and peened finish to the aluminum.  You can paint it, powdercoat it or leave it bare.

[PeWe]

One very effective method of cleaning engine parts is vapor blasting.  Check out www.restocycle.com  It is run by Nils Menten here on the forum (who is also an Ikon suspension dealer).  Vapor blasting leaves a like new and peened finish to the aluminum.  You can paint it, powdercoat it or leave it bare.

Those parts on that site look like art. For a shelf beside the TV in the living room

[SOHC4 Cafe Racer Fan]

One very effective method of cleaning engine parts is vapor blasting.  Check out www.restocycle.com  It is run by Nils Menten here on the forum (who is also an Ikon suspension dealer).  Vapor blasting leaves a like new and peened finish to the aluminum.  You can paint it, powdercoat it or leave it bare.

Those parts on that site look like art. For a shelf beside the TV in the living room

I suppose you could put a piece of glass on top and do that! 

[Stev-o]

One very effective method of cleaning engine parts is vapor blasting.  Check out www.restocycle.com  It is run by Nils Menten here on the forum (who is also an Ikon suspension dealer).  Vapor blasting leaves a like new and peened finish to the aluminum.  You can paint it, powdercoat it or leave it bare.

Those parts on that site look like art. For a shelf beside the TV in the living room

I prefer them on my bike and on the road!

[PeWe]

Maybe late now...about engine paint that was up on previous page.

Do not use the paint for really hot surfaces like exhaust pipes, heat resistant paint 650°C.
This will NEVER harden when applied on cases, cylinder and head. I did that mistake for many years ago when people sprayed the cylinders and heads black. My cylinder softened extra when warm and looked always dirty.
The period of glass beaded cylinders and heads saved the look of my bike.

I used, (and did again yesterday) engine paint for 150°C (300°F). I used it on my Honda cylinder and head too.

[Marissa]

A little progress. Right now I'm having trouble getting the cam chain on the sprocket. I've tried it as many ways possible:

tried getting it on the sprocket first, then cam through,
tried putting the sprocket 1 inch to the left of where it sits, letting it rest and trying to put the chain on that way,
tried putting it through the cam then onto the sprocket, etc.

Before you ask, no the chain isn't caught. I've spun it over multiple times to make sure I wasn't crazy. Am I just not being aggressive enough with it? I was able to get the assembly all together without the chain tensioner installed, but obviously there's no way to install it after. Everything seems to be installed as the cylmer manual says to. The cam guide is on perfectly.
The more I dig, the more issues I find I don't even know if I like this bike anymore, haha.

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr check out my rigged tool to remove a broken cylinder bolt!

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr presents in my oil pan

[goldarrow]

Triple check and be sure that the chain tensioner is seated properly where it belongs, before torque down the head nuts

[goldarrow]

Untitled by Marissa Simos, on Flickr

Untitled by Marissa Simos, on Flickr

Chain tensioner in These pics don't look right

[Scott S]

 It's not. The tensioner isn't seated in the "cup" in the case.

[DaveBarbier]

It's not. The tensioner isn't seated in the "cup" in the case.

+1 Put the tensioner in it's pocket. You'll probably have to lift the head and cylinders a little.

But even with the tensioner in it's pocket it'll probably still be difficult to get the chain and sprocket on the cam.

I put the chain on the sprocket, slide the cam through, then lift the sprocket with chain on the cam. Before this though, I loosen the tensioner's locknut, reach down with a large flathead screw driver and push the tensioner "bow" away from the chain and then tighten the lock nut. That will give you more chain slack.

Progress! Doing good so far!

[Lostboy Steve]

It's not. The tensioner isn't seated in the "cup" in the case.

+1 Put the tensioner in it's pocket. You'll probably have to lift the head and cylinders a little.

But even with the tensioner in it's pocket it'll probably still be difficult to get the chain and sprocket on the cam.

I put the chain on the sprocket, slide the cam through, then lift the sprocket with chain on the cam. Before this though, I loosen the tensioner's locknut, reach down with a large flathead screw driver and push the tensioner "bow" away from the chain and then tighten the lock nut. That will give you more chain slack.

Progress! Doing good so far!

+2 and I usually install mine the same way.


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