Author Topic: Kawasaki Z400J1 Restoration  (Read 228 times)

Online Laverda Dave

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Kawasaki Z400J1 Restoration
« on: January 12, 2021, 12:50:54 PM »
Hi All,

Well, now that I'm locked up again for the foreseeable future and unable to continue with my volunteer tour guide work at the Battle of Britain Bunker and the Bee-keeping is now also in hibernation I needed to look around for something else to do. 

The Triton rebuild I have previously posted about has now come to a complete stop due to being unable to rescue the parts I have in for chrome and zinc plating (it’s been 11 months now), and I need some serious machining work undertaken on the barrel but I am unable to visit the engineer to discuss the work.

My Brother in Law who lives 90 miles away wanted me to finish off getting his inherited 1981 Kawasaki Z400J1 running. As I couldn’t go there he sent the bike up to me via a courier.  I’ve posted previously about this bike and its history via another thread:

http://www.sohc.co.uk/index.php/topic,21367.0.html

When I put the bike on the bench I could see it was in a bit of a sorry state cosmetically. I thought Honda frame paint was thin but Kawasaki took it to another level, it’s not even tissue thin, it appears to be one very quick pass of a spray gun and that was it. The rust is actually coming up from below the paint and causing the paint to flake off in large patches. The engine paint is also really poor, bubbling and blistering and just falling off when I tried to clean it with soap and water with a soft brush.

What with all the above and rear shocks that were so rusty on the piston rods there was no oil left inside them and the petrol tank having serious rust issues on the seams and the same with the front mudguard it was time to bite the bullet and strip the bike. So the BIL has decided to go-ahead with the restoration in memory of his late father who purchased the bike in Guernsey whilst on a week’s holiday (PX’d a 250 Superdream for it). It’s a great shame the bike has ended up in the condition it’s in considering it only has a genuine 350 miles on it, it was never fully run in!

So, the engine is now partially stripped down as far as the crankcases, this will make it light enough I hope to enable me to lift it out of the frame. I have labelled, bagged, taken photos and made copious notes of everything as I’ve stripped it. I will repaint the cases and get the frame and all brackets etc powder coated. I’ll send the zinc and chrome parts off to Allen chrome in Hull as he seems to get some good reviews by forum members so worth a try.
My first impressions of the bike are it’s so heavy and over-engineered! The rear shock mounting bolts for example are 17mm, Honda 400/4’s are 14mm, the castings are also a lot thicker and heavier, the cams also have separate bearing caps and a cam cover! 

I know it’s a Kawasaki and not a Honda and it’s got two cams and not one but I guess it’s always good to read about a restoration in the winter to keep us all going. And remember, this is the bike Kawasaki thought would be a successor to the Honda 400/4.

I’ll post progress photos as I go along, here some for now.

Dave
1976 Honda 400/4
1981 Honda CB250RSA
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1982 Laverda 120 Jota
1924 Triumph 550SD
2012 Stanley Battery Drill

Online Laverda Dave

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Re: Kawasaki Z400J1 Restoration
« Reply #1 on: January 12, 2021, 12:54:34 PM »
A few more
1976 Honda 400/4
1981 Honda CB250RSA
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1982 Laverda 120 Jota
1924 Triumph 550SD
2012 Stanley Battery Drill

Offline AshimotoK0

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Re: Kawasaki Z400J1 Restoration
« Reply #2 on: January 12, 2021, 01:44:32 PM »
Really looking forward to posts on this Dave. Such a shame that it has corroded so badly and interesting to compare with the Honda model.

In the early 80's a lad at work dropped his Yellow 400F at low speed and even though the damage was only a dented tank and a torn seat plus mirrors and other very minor damage plus less than 10k miles, the insurance company deemed that the new parts were so expensive that they wrote it off. I bought the salvage, swapped over a tank and seat I had  already, refitted the original air filter system and I was away. Sadly about six months later it was nicked from where I worked. The lad I got it form, decided he had had enough of Honda's and bought a Z400J, which he said he really enjoyed riding, although personally I much preferred the Honda (not it's replacement the 400T though, give me the 400J any day). At the time I didn't even know that the 400J existed and if they did sell in any quantity over here, I have never seen one since my mate at work had one. Not sure if it's true but I think I  heard a few years ago that they are much sought after in Japan ...... but that may be cobblers. 
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Offline Rozabikes Tim

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Re: Kawasaki Z400J1 Restoration
« Reply #3 on: January 12, 2021, 02:29:26 PM »
I have it in mind Suzuki did a 400/4 for a bit too or is it a case of dodgy memory.....

Yes Dave bring it on lets follow this!
One day I'll have the time to restore it, not just talk and dream....

Online SteveD CB500K0

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Re: Kawasaki Z400J1 Restoration
« Reply #4 on: January 12, 2021, 02:31:14 PM »
I think the GS400 was a twin.


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Offline Rozabikes Tim

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Re: Kawasaki Z400J1 Restoration
« Reply #5 on: January 12, 2021, 02:34:27 PM »
I know there was a twin but something is saying a 4 too???  Was it a GSX 16 valver?
One day I'll have the time to restore it, not just talk and dream....

Offline Rozabikes Tim

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Re: Kawasaki Z400J1 Restoration
« Reply #6 on: January 12, 2021, 02:37:51 PM »
Bless Google [ Guests cannot view attachments ]

One day I'll have the time to restore it, not just talk and dream....

Offline SumpMagnet

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Re: Kawasaki Z400J1 Restoration
« Reply #7 on: January 12, 2021, 03:05:06 PM »
The Z400J was basically a sleeved down 500 .... and they stretched it to a 550 as well. So the 400 is very understressed. I had one back in the day, and it was a tough old beast. But...yes...the cosmetics were awful in terms of paint quality. It was a good solid everyday machine.

I had a GSX400F as well. Loud Alfa pipe...it was a buzzy little thing, but fun in the right conditions. I took it on a weekend trip from London to Aberystwyth...and I was utterly shattered when I got back. It was never in the power and never in the right gear on the twisties, or on the main roads. Was the first and only bike I have had with a gear indicator on it. Oh..look..I'm in 6th.... I didn;t care then...and IO wouldn;t care now! Had a sticky cam chain tensioner....which meant you would start it up one day and it was smooth and silent. Next day...it would rsattle like it was about to die! I convinced myself it wass a baby Katana...and lived with it until something better came along!
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Online Laverda Dave

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Re: Kawasaki Z400J1 Restoration
« Reply #8 on: January 13, 2021, 07:48:09 PM »
A bit more progress today aided by a packet of fig rolls!

The head came off with a few taps. I fully stripped it and cleaned all the parts in the trusty parts washer. All now left to dry overnight before bagging up. No wear at all in the barrels and they still have some feint honing marks. I cleaned the top of the pistons while the barrels were still on (same with the combustion chambers). A big sigh of relief when I found no rust in the bores and none of the rings were broken or stuck in the pistons after spending 39 years in the same place in the bores!

Tomorrow will be more stripping of the engine and removing it from the frame. Only issue so far are removing the gaskets, Kawasaki must have invented superglue, they are stuck fast and take a good soaking before they even start to give up their grip on metal!

A question for anyone who knows about Kawasaki's, can the rubber pucks on the end of the cams be reused or should they be replaced? They are held in with liquid gasket.

Ash, I checked out a few Japanese websites, appears that even ratty Z400J's sell for upwards of £7k! Problem is these are dealer prices and then there's to £2k shipping costs etc. I hope the bil will want to keep it and get a bike license to actually ride it!
1976 Honda 400/4
1981 Honda CB250RSA
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1982 Laverda 120 Jota
1924 Triumph 550SD
2012 Stanley Battery Drill

Offline Bryanj

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Re: Kawasaki Z400J1 Restoration
« Reply #9 on: January 13, 2021, 08:26:16 PM »
Are you meaning the half moon bits held down by the rocker cove? If dont ever remember changing any BUT these are now a lot older!

Online Laverda Dave

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Re: Kawasaki Z400J1 Restoration
« Reply #10 on: January 13, 2021, 08:43:41 PM »
That's the ones Bryan. They are still pliable hence my question if they can be re-used. The motor has hardly been used so maybe it's because they've not been through endless heat cycles they could still be useable. The cam chain tensioner system is of an industrial
scale compared to a Honda 400/4!
1976 Honda 400/4
1981 Honda CB250RSA
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1982 Laverda 120 Jota
1924 Triumph 550SD
2012 Stanley Battery Drill

Offline SumpMagnet

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Re: Kawasaki Z400J1 Restoration
« Reply #11 on: January 13, 2021, 08:50:35 PM »
If they are still pliable, then they should be fine. Just so long as they keep the oil in.
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline AshimotoK0

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Re: Kawasaki Z400J1 Restoration
« Reply #12 on: January 13, 2021, 10:45:16 PM »
Seems that the rumour i heard was true  ;)

http://motorcycle.goobike.com/motorcycle/bike/stock_8201718B30200

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“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

 

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