Topic: 1977 CB750 K7 Resto-mod, Knoxville

[AintNoEasyWay]

Engine is done. Time to paint.

[Restoration Fan]

AWESOME!  Getting close to riding time now, Nate.

[AintNoEasyWay]

Stripped paint tonight. Holy $&@! What a mess! Managed to get most of it off, but I'll go back over it tomorrow evening with brass brushes & scotch pads. Then I'll have Friday night to do a few more degreases & wash downs. I plan to use Saturday & Sunday for paint.

[AintNoEasyWay]

Ok, went over the engine with brass brushes & a red 3M sanding sponge I had. That shined up the engine really well & got pretty much all of the remaining paint off. Then sprayed on degreaser & rinsed down with a hose. Went over all of it with the air compressor & some towels to get it all as dry as I could.

Hopefully any remaining water will dry overnight. I will wipe down with acetone tomorrow at lunch, then go ahead & spray the primer coats tomorrow evening. Hope I've done enough prep & I'll have a successful paint job for a long time!

[SOHC4 Cafe Racer Fan]

Give it 2-3 wipes with acetone.

[AintNoEasyWay]

Give it 2-3 wipes with acetone.

Hey Cafe Fan, thanks for the input. I found your old thread on engine paint here: http://forums.sohc4.net/index.php?topic=114550.0

Did you end up using a process similar to what MadScientist describes in that thread?

[AintNoEasyWay]

I'll be using VHT primer, paint, and clear on the engine. All of them are high temp up to 550 degrees fahrenheit.

Since I'll be spraying the engine while it's all together, I was considering using a heat gun before and between coats to help the paint dry properly (I don't have the option to bake pieces in any kind of oven). Has anyone tried this?

[Restoration Fan]

Nate,
See if you can find a large cardbox box that's a good bit larger than your engine.  Line the interior of the box with aluminum foil and then make a hole in the side of the box large enough for you to safely put the heat gun through into the interior of the box.  If you really want to be clever, take a kitchen thermometer and stick it through to the interior of the box so you can see just how high you're getting the interior of the box.

That should be more than sufficient for you to get even heat onto the engine and cure the VHT paint because it doesn't require a super high heat.  I think it's just like 240 for an hour or something like that.

Question:  are you planning to paint the valve cover?   If  you're not taping that and are going to paint those, then you should loosen your tappet covers.  Leave them on so you don't get paint inside the engine but you wanna make sure those don't get painted shut.

[AintNoEasyWay]

Nate,
See if you can find a large cardbox box that's a good bit larger than your engine.  Line the interior of the box with aluminum foil and then make a hole in the side of the box large enough for you to safely put the heat gun through into the interior of the box.  If you really want to be clever, take a kitchen thermometer and stick it through to the interior of the box so you can see just how high you're getting the interior of the box.

That should be more than sufficient for you to get even heat onto the engine and cure the VHT paint because it doesn't require a super high heat.  I think it's just like 240 for an hour or something like that.

Question:  are you planning to paint the valve cover?   If  you're not taping that and are going to paint those, then you should loosen your tappet covers.  Leave them on so you don't get paint inside the engine but you wanna make sure those don't get painted shut.

Very solid advice. Thanks, Ron! I'm going to leave the cam cover polished but paint that angled piece that sits in the very center of the cam cover. It has three screws on the outside and two that go beneath it into the cylinder head. Not sure what it's called.

I'll probably use that as a test piece for paint before I begin going over the whole engine, since it's so small. I'll tape up the cam cover while painting. I assume the paint tape will hold up in the make shift oven?

[SOHC4 Cafe Racer Fan]

Did the repeated acetone wipe downs. I recommend the hot box even though I didn't do it. Someone came up with the foil-lined box later. Really great idea.

[Restoration Fan]

I'll probably use that as a test piece for paint before I begin going over the whole engine, since it's so small. I'll tape up the cam cover while painting. I assume the paint tape will hold up in the make shift oven?

I don't know if it will or not.  That tape is paper-based so it might burn.

[AintNoEasyWay]

I had a red scotch brite pad out to go over my engine last night & saw my dirty, rusty headers sitting in the corner. Figured I'd use the pad on those too while I was at it. The headers cleaned up really well to my surprise. The black is a little dull though, so I'm considering still repainting them. What do you guys think? My engine will be black as well so I don't want any major contrast between the too. I'll just have to see once I paint the engine.

If I repaint the headers, does the original black need to come off completely or can I paint over that once I've sanded & prepped with some kind of solvent?

Either way, I really need to clean up/de-rust these exhaust collars to get them looking nice. Those stoppers that prevent the collars from coming off (pictured to the right of the collar in the photo below), what are they called & how do I remove them? They seem to just bend off from one side if I pull them off, but I'm not sure & don't want to damage them. They are also pretty damn rusty.

[Restoration Fan]

Nate,
Those little pieces that fit underneath the exhaust collars should be 2 separate pieces.  They should just separate and pull right off.  Put a scotch brite pad on your drill or one on your Dremel and you should be able to sand the rust right off them. 

Or you can purchase a gallon of Metal Rescue and put them and the exhaust collars into it.  It'll take that rust right off of it all.

Regarding your headers, I personally think they look fine as they are but if you want to paint them, just make sure there's no flaking or missing paint.  If there is, you should probably put some stripper on them and remove the paint before spraying them.  If the paint on there is in good shape, just give it a light sanding with some rough grit sandpaper to give the surface some tooth for the paint to grab onto.

[Wobbly]

If they are too far gone (yours are trashed), you should just replace the exhaust-pipe-joint collars. They are still available from Honda (8 x part # 18233-392-000). The joints should clean up okay.

[madmtnmotors]

The collars for the Mac headers are different than the stock collars....

[AintNoEasyWay]

Damn, the stock pipe-joint collars are insanely expensive!

madmtn, if you're right, I'll have to find ones for the mac. Maybe I can get a better price on those.

[Wobbly]

Damn, the stock pipe-joint collars are insanely expensive!

Think so? Wait until they are no longer available from Honda, and then check prices.

[Wobbly]

$ 9.32 a piece at Discount Honda. http://www.discounthondaparts.com/fiche_section_detail.asp?section=2451916&category=Motorcycles&make=Honda&year=1977&fveh=131105

But , indeed, the stock spacer collars won't fit on the MAC pipes.

[madmtnmotors]

That appears to be a Mac header. I do not believe that stock collars will even work. IIRC the Mac pipes are larger O.D. than stock...

Mac collars required.

[AintNoEasyWay]

I'm gonna sock them overnight in rust remover & we'll see what happens. In the meantime, I'll go ahead & start searching for some new ones. Thanks guys.

[madmtnmotors]

There doesn't appear to be anything wrong with the ones you have. The Mac collars are thinner tin and often have a little bit of material joining them together on one side. After enough removals and installs the two halves usually separate but are still fully functional, just now in two separate halves no longer joined. They don't have to look pretty since they can't be seen when installed.

I would try them before replacing them.

[AintNoEasyWay]

There doesn't appear to be anything wrong with the ones you have. The Mac collars are thinner tin and often have a little bit of material joining them together on one side. After enough removals and installs the two halves usually separate but are still fully functional, just now in two separate halves no longer joined. They don't have to look pretty since they can't be seen when installed.

I would try them before replacing them.

Sweet. Each of mine do still have a small piece on one side joining them together.

My engine is all prepared & taped off for paint. I also had to make a hot box by joining a couple boxes together & getting crafty with duct tape since I wasn't able to find a box that would do the job right off the bat. Tomorrow I'll put down at least the primer coats & base color, then go ahead & cure the engine in the hot box.

After the engine's painted, I'm going to have to deal with some corrosion on my swing arm/frame where battery acid leaked. I've read this is a common problem to come across (just another side effect of the PO letting it sit for 3 years). I'll go ahead & take off the swing arm & replace the bushings with some bronze bushings I bought last fall. Might as well go ahead & change out the rear wheel bearings while I'm at it too.

[Wobbly]

madmtnmotors is correct (as usual): the original ones won't fit. If the pictured ones are for the MAC--no wonder they look trashed to me. I thought those were the original Honda ones-and for that they look mighty disfigured. 

[AintNoEasyWay]

Cleaned up those collars with an overnight soak in some WD40 rust remover.

Will start priming the engine after lunch.

[AintNoEasyWay]

Ok, primer & black coats are on the engine & I just heated the engine inside my aluminium foil lined hotbox for an hour at ~200 F. I'll let it cool overnight & then apply clear coat tomorrow during my lunch break.

I'm going to sand the sides of the fins down for the polished, bare metal look. Should I do it before or after I apply the clear coat? Let me know what you guys think.