Author Topic: 1977 CB750 K7 Resto-mod, Knoxville (Read 97722 times)

madmtnmotors · « **Reply #350 on:** June 27, 2015, 06:02:00 PM »

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 · « **Reply #351 on:** June 27, 2015, 06:12:32 PM »

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 · « **Reply #352 on:** June 27, 2015, 06:18:32 PM »

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 · « **Reply #353 on:** June 27, 2015, 06:30:21 PM »

Quote from: madmtnmotors on June 27, 2015, 06:18:32 PM

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 · « **Reply #354 on:** June 28, 2015, 01:18:02 AM »

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 · « **Reply #355 on:** June 28, 2015, 07:30:16 AM »

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

Will start priming the engine after lunch.

AintNoEasyWay · « **Reply #356 on:** June 28, 2015, 03:33:17 PM »

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.

Desert-SOHC · « **Reply #357 on:** June 28, 2015, 06:08:42 PM »

oohhh pretty

Restoration Fan · « **Reply #358 on:** June 29, 2015, 01:04:56 AM »

Nate,
If you want the bare look, you need to sand them down before you put the clear coat on it.

Really nice job on the paint. It looks fantastic!

AintNoEasyWay · « **Reply #359 on:** June 29, 2015, 02:54:07 AM »

Thanks guys!

So if I sand down the fins before clear coat, I guess I'd have to clean the engine back up, get all the sanded paint off before applying the clear coat. Can I just wipe it down with acetone to get it clean again? Seems like I'd have to rinse it all down again with a hose.

Also Ron, you suggested not to cure in the hot box after applying the clear coat, but the VHT clear coat can has the same instructions for curing paint as the engine enamel can -- 1 hour at 200 F. Is there a reason for not curing the clear coat in the hotbox? Won't the engine reach this temp when it's back in the bike anyway? Maybe I misunderstood your text.

calj737 · « **Reply #360 on:** June 29, 2015, 03:30:18 AM »

Don't use acetone to clean the fins of paint. You won't be able to control where it goes, and you'll take paint from areas you didn't intend. Use a sanding block wi enough to span several fins at once. Sand in a single direction, and the fins will be revealed. Diligent, light pressure, and not too rough a grit.

AintNoEasyWay · « **Reply #361 on:** June 29, 2015, 05:27:04 AM »

Ok guys, here's my plan then:

I'll sand the fins tonight, cover the crankcase & other parts of the engine below the fins to try to keep them clean. My concern is how do I remove the mess I've sanded off so that the paint is still clean for clear coat?

I guess once I'm done sanding I'll clean with air and a damp cloth? Should I reheat the paint again to get all the moisture off before clear coating?

P.S. I saved some advice I wrangled from other threads, hope you guys don't mind I repost it here in case anyone else needs help with sanding fins as well:

Quote from: calj737

To polish the edges of the fins after painting, use a dremeled or sanding block to scrape away the paint. Then green, red, then grey scotch brite pads. One direction for your sanding motion and don't press hard.
...
Sand the fins after the final paint job, it will be easier to keep the paint off them while spraying.

While the prep wasn't perfect before priming, at the end of the day, much of it wont show as the backside is covered by the carbs, and not many eyeball between the fins. Bikes tend to be admired from a few feet away, and the whole appearance of the bike will be beautiful.

Use a sanding block when you attack the fins to help avoid the paper from traveling in between the edges. It will make it much easier to control and you'll come out aces!

Quote from: mkoski

Sure, its actually a really simple process. I didn't really read up on it or anything, I just grabbed some coarse, medium and fine emery cloth (sandpaper would work fine!) and sanded the paint off the fin ends with a sanding block. With the way the fins are cast there are a few high/low spots so I did a bit of sanding without the block as well so that the exposed metal was consistent. One thing I noticed is that I didn't get lines as clean as I hoped where the paint meets the bare metal (big jagged in spots). I will sharpen the lines a bit just by going over them again carefully with fine emery paper again.
...
I should mention my method, actually, as it might help some others out. I first went at it with a block and some medium grit emery cloth to remove most of the paint and then hand sanded with fine emery cloth. This brought it to a decent level but it still wasn't quite to my liking. I decided to try using my 4.5" grinder with a hard foam polishing wheel (which is too hard/fast to polish metal properly) and went along the fins with that. It came out gorgeous. The paint is sanded into really nice lines and the bare aluminum underneath is gleaming.

Restoration Fan · « **Reply #362 on:** June 29, 2015, 07:14:17 AM »

Your plan sounds solid, Nate. Just cover the stuff you don't want to sand. Use the sanding block and sand the edges of the fins. You're going to be surprised at how little you're going to have to sand to get the edges of those fins bare of paint.

Once you have them like you want them, use air and a damp cloth, followed by air again to blow all of the dust residue away.

Then you can clear coat. If you're using a VHT clear coat that says to cure it, then by all means use your heat box again to cure the clear coat after it has been applied. I was referring to the clear that we used, which did not require a heat curing.

AintNoEasyWay · « **Reply #363 on:** June 29, 2015, 07:32:13 AM »

Quote from: Restoration Fan on June 29, 2015, 07:14:17 AM

Your plan sounds solid, Nate. Just cover the stuff you don't want to sand. Use the sanding block and sand the edges of the fins. You're going to be surprised at how little you're going to have to sand to get the edges of those fins bare of paint.

Once you have them like you want them, use air and a damp cloth, followed by air again to blow all of the dust residue away.

Then you can clear coat. If you're using a VHT clear coat that says to cure it, then by all means use your heat box again to cure the clear coat after it has been applied. I was referring to the clear that we used, which did not require a heat curing.

Excellent. Thanks, Ron.

I've also gotta get my rear wheel off to replace the sprocket and of course to remove my swingarm and replace bushings there. I don't have sockets large enough to deal with the nuts on the rear wheel and swing arm, so I'll have go to get those tonight. Oh, and I totally forgot that I want to paint the angled piece that sits atop the cam cover (it's been covered up with the rest of the cam). Now I'll have to go buy more paint since I used all my primer and black on the engine.

I also need to get some carb float drain tubes. My bike didn't have any when I bought it, and I'd hate to ruin this paint if I get a leak when I first start the bike back up. I think I've seen flybox1 say that you can use windshield wiper tubes or something for this? I'll have to do some searching, but maybe one you knows right off hand of an alternative to the originals.

AintNoEasyWay · « **Reply #364 on:** June 29, 2015, 11:30:26 AM »

Anyone have an idea why swing arms are so cheap on eBay? I was expecting them to be significantly higher.

SOHC4 Cafe Racer Fan · « **Reply #365 on:** June 29, 2015, 03:15:55 PM »

If it's a stock bike, they are not worth much without the rest of the chassis. If you are replacing the stock 750 arm, you may want to swap it out for a 550 arm (approx. 1 inch longer). Or, if you are going FULL restomod, check out the MotoGP Werks/CalFab aluminum swingarms (not cheap), or you can have CMR Racing in Canada make you a boxed-style race arm out of chrome-moly.

AintNoEasyWay · « **Reply #366 on:** June 30, 2015, 09:34:35 AM »

Sanded the fins down last night. I was hoping to clear coat today but there are a couple areas I want to touch up with black paint first. Clear coat will have to wait until tomorrow. The closer things get to completion, the harder it becomes not to rush things. It's really hard to resist right now. I just want it back in the bike so I can see whether or not the rebuild was a success. Life lessons...

calj737 · « **Reply #367 on:** June 30, 2015, 09:44:15 AM »

looks pretty darn nice from here!

AintNoEasyWay · « **Reply #368 on:** June 30, 2015, 09:47:25 AM »

Thanks, cal!

When I spray the clear coat, should I leave the chrome pieces and polished cam cover taped off? I assume I should only clear coat what I've painted, but just want to be sure.

calj737 · « **Reply #369 on:** June 30, 2015, 09:48:21 AM »

Correct, protect what you don't want cleared. Either remove or cover it.

Are you replacing the stock fasteners? I noticed you left them in place and painted them.

70CB750 · « **Reply #370 on:** June 30, 2015, 09:51:33 AM »

Quote from: AintNoEasyWay on June 30, 2015, 09:34:35 AM

Sanded the fins down last night. I was hoping to clear coat today but there are a couple areas I want to touch up with black paint first. Clear coat will have to wait until tomorrow. The closer things get to completion, the harder it becomes not to rush things. It's really hard to resist right now. I just want it back in the bike so I can see whether or not the rebuild was a success. Life lessons...

Is it gunmetal color?

AintNoEasyWay · « **Reply #371 on:** June 30, 2015, 09:59:49 AM »

Quote from: calj737 on June 30, 2015, 09:48:21 AM

Correct, protect what you don't want cleared. Either remove or cover it.

Are you replacing the stock fasteners? I noticed you left them in place and painted them.

Yes, I have all new fasteners from here: http://www.metrocast.net/~spillane/index_004.htm. So I'll replace those after all the paint is finished.

Quote from: 70CB750 on June 30, 2015, 09:51:33 AM

Is it gunmetal color?

Hey 70, are you referring to the clear coat? Not sure what you mean. Here's the clear coat I have: http://www.amazon.com/VHT-SP145-Engine-Enamel-Gloss/dp/B000CPIMW6. It's gloss, so I'm guessing this is going to affect the way the black looks. I used VHT flat black for the paint.

I think I'd like it to have more gloss to the finish. What do you guys think? I have to go pick up more black paint this evening so I could always get a different clear coat too.

70CB750 · « **Reply #372 on:** June 30, 2015, 10:01:05 AM »

No the actual color of the engine.

AintNoEasyWay · « **Reply #373 on:** June 30, 2015, 10:03:28 AM »

Quote from: 70CB750 on June 30, 2015, 10:01:05 AM

No the actual color of the engine.

I just used two cans of VHT flat black SP130. It may appear like gunmetal in some areas because of the way the light hits it. Which is okay with me because my tank has a similar stripe down it.

calj737 · « **Reply #374 on:** June 30, 2015, 10:04:06 AM »

I prefer a satin finish on the engine, personally. I like semi-gloss to gloss on the frames. The satin is a bit more contemporary in my opinion.

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Author Topic: 1977 CB750 K7 Resto-mod, Knoxville (Read 97722 times)

Wobbly