Author Topic: Maui Z1 1973  (Read 47519 times)

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Offline PeWe

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Re: Maui Z1 1973
« Reply #550 on: November 12, 2021, 12:57:35 AM »
Enough to clean them?
Original paint looks good !
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline MauiK3

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Re: Maui Z1 1973
« Reply #551 on: November 12, 2021, 07:01:43 AM »
For my smashed tank that has very little rust I'm going to try to set up an electrolysis rig to clean the rust out. I'll post progress.
One reason is that none of the usual products is available here.
I could try vinegar and baking soda but I think if I can get electrolysis to work it will be gentler on the metal, may take longer but I have time.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Terry in Australia

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Re: Maui Z1 1973
« Reply #552 on: November 12, 2021, 11:42:10 PM »
For my smashed tank that has very little rust I'm going to try to set up an electrolysis rig to clean the rust out. I'll post progress.
One reason is that none of the usual products is available here.
I could try vinegar and baking soda but I think if I can get electrolysis to work it will be gentler on the metal, may take longer but I have time.

Just do it in a well ventilated area (preferably outside) Steve, none of the pro-electrolysis guys mention the hydrogen gas produced in de-rusting a tank will blow your tank (and you) into another neighbourhood if you create a spark in an enclosed space. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline RAFster122s

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Re: Maui Z1 1973
« Reply #553 on: November 13, 2021, 03:29:32 AM »
Capture the hydrogen gas and if you put it in a plastic bag you can have some fun safely lighting it on fire in a controlled area...
David- back in the desert SW!

Offline Alan F.

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Re: Maui Z1 1973
« Reply #554 on: November 13, 2021, 05:44:31 AM »
It won't be so much hydrogen and oxygen produced so as to cause a dangerous situation unless you happen to be in an airtight space. They say most buildings completely change out interior air every 3 hours? That's a lot of air leaks. Just use a ventilated area without open flame or sparks and you'll be ok. Warm environments work better than cold.

And if you ever want to remove the paint from a tank at the same time, submerge the whole thing in the washing soda solution and turn on the battery charger, that stubborn paint will just flake right off after a while.

Offline MauiK3

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Re: Maui Z1 1973
« Reply #555 on: November 13, 2021, 07:07:04 AM »
My first try is modest, just to see how it goes. I have it outside, a small twisted iron tie wire suspended in the tank with tape at key points to prevent a dead short. If it's not enough I may just go get a bin and submerge the tank but I question if that will work with what's inside the tank. I'm hoping patience pays off.
My charger is set on 2 amps but I may try the 12 amp setting.
This tank effort may not work but it's worth a try to save the original tank.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Alan F.

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Re: Maui Z1 1973
« Reply #556 on: November 13, 2021, 08:35:24 AM »
It'll work, just check your electrode every few hours, it will need cleaning and you will be surprised at the amount of crud it will attract.

Offline grcamna2

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Re: Maui Z1 1973
« Reply #557 on: November 13, 2021, 12:54:53 PM »
The top of motorcycle fuel tanks rust quite a bit over time:find a small telescoping mirror and a light and you'll see.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline MauiK3

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Re: Maui Z1 1973
« Reply #558 on: November 13, 2021, 01:45:04 PM »
It’s been going all morning, I’m going to drain it, clean up, inspect and get it going again. It’s only water and washing soda, no big expense.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Alan F.

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Re: Maui Z1 1973
« Reply #559 on: November 13, 2021, 02:28:03 PM »
You shouldn't need to, I'd just top off. But yeah it's cheap stuff. Very, very good value per dollar, per effort for the results achieved with the osmosis de-rusting method.

I'd suppose for those that have a lot of iron in their water this process will work slightly faster, it takes a bit for those iron ions to reach saturation in the solution before the reaction starts. (I think I stated that correctly)
« Last Edit: November 13, 2021, 02:31:12 PM by Alan F. »

Offline Terry in Australia

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Re: Maui Z1 1973
« Reply #560 on: November 13, 2021, 04:49:13 PM »
It won't be so much hydrogen and oxygen produced so as to cause a dangerous situation unless you happen to be in an airtight space.

I'd be very careful Alan, I had a bike battery explode in an open garage that was certainly nowhere near "airtight", and the damage it caused was scary. I don't know how much more hydrogen is produced by a battery charging than de-rusting a fuel tank, but it's not something to ignore. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline Alan F.

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Re: Maui Z1 1973
« Reply #561 on: November 13, 2021, 07:30:20 PM »
I'm always careful, I learned shop safety from a nine-fingered shop teacher like everyone else.

Offline MauiK3

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Re: Maui Z1 1973
« Reply #562 on: November 14, 2021, 07:19:56 AM »
My setup is outside, no worries.
No pictures ready to post yet but I'm pleased to report that when I changed the fluid and cleaned the electrode yesterday it was looking very promising. I had to refill it so the roof of the tank was covered better.
Along the way the lower half of the engine went back in the frame without incident. Many thanks to my bride of 43 years for the assist.
My two light harnesses came in for the gauges. One was clearly not new old stock, it was old old stock. Had one socket missing the spring and contact. Oh well, my old ones were disintegrated so it's better. I managed to salvage the missing parts from my old ones and solder the contact on where needed, it all works now.
Photos to come.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline MauiK3

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Re: Maui Z1 1973
« Reply #563 on: November 14, 2021, 02:28:33 PM »
Half of the motor in the frame
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline MauiK3

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Re: Maui Z1 1973
« Reply #564 on: November 14, 2021, 02:32:03 PM »
You will laugh but this bit of twisted rebar tie wire is slowly working. The tape keeps it from shorting
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Alan F.

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Re: Maui Z1 1973
« Reply #565 on: November 14, 2021, 02:49:01 PM »
That's really good that it gets down into both sides of the tank. What an ugly bunch of soup that cooks up!

Offline Terry in Australia

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Re: Maui Z1 1973
« Reply #566 on: November 14, 2021, 03:08:07 PM »
That’s looking good Steve, well done. I imagine that your tank guy will need to cut the bottom out to fix those massive dents anyway, so he can probably clean out any places that you miss with his wire brush. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline MauiK3

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Re: Maui Z1 1973
« Reply #567 on: November 14, 2021, 04:35:40 PM »
Yes, I’m not at all sure how he will do this. A stud gun and heat with a slide hammer may do it too.
Hard to say, I’d like to be there but that would be costly.
Fly to Oahu
Car
Hotel
Meals
Parking(parking is expensive there)
I may go over to pick it up, when we fly Mokulele Air they use 9 passenger Cessna 208’s, no TSA and they are very careful with cargo, you get to watch them load. I can buy a bin large enough, figure out a padding scheme and almost hand carry it back, for what it will cost it will be worth it to avoid shipping damage.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Terry in Australia

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Re: Maui Z1 1973
« Reply #568 on: November 14, 2021, 05:50:14 PM »
Yep, I’ve got a very expensive stud welder that I bought here for a couple of thousand bucks when I was fixing cars, if he can secure the tank so it won’t move he may be able to pull it, but back in the day the trick for damage that bad was to cut the bottom out (easy nowadays with a plasma cutter) bash it out from the inside and weld it back together. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline grcamna2

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Re: Maui Z1 1973
« Reply #569 on: November 14, 2021, 08:59:28 PM »
Yep, I’ve got a very expensive stud welder that I bought here for a couple of thousand bucks when I was fixing cars, if he can secure the tank so it won’t move he may be able to pull it, but back in the day the trick for damage that bad was to cut the bottom out (easy nowadays with a plasma cutter) bash it out from the inside and weld it back together. ;D

I had a fuel tank done professionally where they cut about a 1/2 section piece in the center of the bottom-tunnel area of the tank(away from the front and rear mounts)out,pushed-out the little dents(there weren't many on mine)then sand blasted the entire inside and then nicely welded the bottom section back on.The company then coated the entire inside of the tank with their special coating to inhibit any more rust from ever forming inside there for the life of the tank;the name of the company is 'gas tank renu' and can be looked-up online;they have shops in different locations:I think they have one over in Oahu also? The job is guaranteed for life never to rust inside again;they stand behind their guarantee and will completely restore it for free if it has a problem in the future.I think it's an excellent investment if you plan on keeping your bike.
« Last Edit: November 15, 2021, 12:54:03 PM by grcamna2 »
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Terry in Australia

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Re: Maui Z1 1973
« Reply #570 on: November 14, 2021, 10:13:54 PM »
That sounds like a great business to start Bill, I ground the braze off a K3 tank and seperated both pieces, and it was dead easy to bash the dents out. My bike had been personally imported from Japan, and fell over in the ship, so had a "Pole sized" dent in the tank. Would have been a bugger to pull out as it creased the tank good, but came out easy from within. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline MauiK3

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Re: Maui Z1 1973
« Reply #571 on: November 15, 2021, 10:39:27 AM »
It's hard to get a good photo of the tank interior but it looks ok, no flaky areas. I stopped here, dried it out with my heat gun and fogged it with some electrical spray I have that makes a nice fog in the tank and prevents rust and isn't too runny so the tank can be fixed and painted. I may run a filter on the fuel line at first so I can trap any stuff I've missed.

1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline grcamna2

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Re: Maui Z1 1973
« Reply #572 on: November 15, 2021, 12:58:04 PM »
Steve,have you considered adding a small container of BB's ?
I do that when I get a rusty tank and then shake that tank all around for as long as i can hold my arms up(it's great exercise :o :))and then I remove every last steel BB with a small telescoping magnet and rinse the tank multiple times then dry it:guarantees you get all the loose,flaky rust removed.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline MauiK3

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Re: Maui Z1 1973
« Reply #573 on: November 15, 2021, 03:18:27 PM »
That’s a good idea to get some of the stuff I could not get.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Terry in Australia

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Re: Maui Z1 1973
« Reply #574 on: November 15, 2021, 04:09:49 PM »
I saw a guy tipped some steel screws and nuts into a rusty tank, wrapped a big blanket around his tank and jammed it into his tumble dryer (so it wouldn’t thump around inside the dryer) with the heat turned off and let it rotate for an hour, and the inside looked like new. ;D
« Last Edit: November 16, 2021, 01:10:48 AM by Terry in Australia »
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)