Kawasaki Z400J1 Restoration

[taysidedragon]

Laverda Dave, when you talk about bolt sizes in a couple of posts, 17, 14 and 10mm, you're talking about hexagon, ie. spanner sizes, not thread sizes I take it.

[AndyD]

Dave,
Looks a great base for restoration - will be good to see how it truns out.

I've had vapour blasting done a few times and I think the key is if there are any inaccessible dead ends, how clean the parts are before blasting (avoiding grit traps) and very careful cleaning afterwards. Most recently used a guy in Slough and they seem to do a really good job and parts come back really clean. I did try on one engine to bung up all the possible grit traps with silicon bungs and this worked to a large extent with only a few being dislodged during blasting. I then spent hours cleaning, flushing and blasting air through everything possible. There's always a small lingering doubt that some grit remained but fingers crossed and the results are aesthetically really pleasing.

Had a look in my fiche collection and I've got a few for the Z400J and happy to scan one assuming the scanner and PC still work (always mention that as the kit is quite old and sat in a cold garage!).
I've got 3 fiches as photo - [ Guests cannot view attachments ]
It takes a while to scan and save the fiches but if you have an urgent area you need first I can always scan a couple of pages quickly and follow with the full fiche if that keeps things moving for you.
Cheers,
Andy

[Laverda Dave]

Laverda Dave, when you talk about bolt sizes in a couple of posts, 17, 14 and 10mm, you're talking about hexagon, ie. spanner sizes, not thread sizes I take it.

Hi Taysidedragon, yes, I normal quote by spanner size but.........I was asked the other day for the tread size as I was unable to provide a part number! The flanged bolt I need has a 12mm head with a 8mm thread size. I have been asked for a thread size before when I was restoring the Morini. The bolt that hold the petrol tank on has a 10mm spanner size, this normally equates to a 6mm thread but on this bolt the thread size is actually 7mm.

AndyD
Thank you for your kind offer, that would be a lifesaver. It's the engine parts list I am after most as that's where I need the O-ring sizes and part numbers for the bolts etc. I tried to place an order with CSMNL as although they dont show the bike in their parts list they do have a printed copy they can refer to. Sounds great but you cannot converse with them by phone only raise what they call 'a ticket' via email. I then had to try and explain the locations of the O-rings and bolts I needed via an email. After waiting two days for a response they said I need to advise them what page in the parts list the part was on! I gave up, if I had the page myself I could have given them the part number . I'm not sure if CSMNL are going to hike their already expensive prices even higher now we are out of the EU?

Ash, thank you for the link, I hadn't seen that listing, I did see one in the USA but it was over £40 exc shipping. Aas its not my bike (or my money) going into the restoration I dont think the BIL will be intrested in spending even more money especially when I tell him the news about the rusty clocks . Hopefully though AndyD has come to the rescue .

I forgot to mention in my update yesterday what I found with the piston rings. When I carefully pulled the barrels off I checked the rings for sticking. They were all 100% in top health but.....on three of the pistons the gap in the top ring was directly +/-5deg in line with the second ring gap! Same applied to the oil rings, none of them were more then 30deg spaced from the ring gap above. All the piston rings were between the 9 & 1 o'clock positions on the pistons. I have been told to gap the rings out at 120deg and three part oil rings at 20mm gaps. Kawasaki must have had a fast production line going and the engine assembly line must have struggled to keep up with demand?

I can also see why Kawasaki are called Kawasaki Heavy Industries, everything on this bike is big and heavy. I need to compare the kerb weight of the Honda 400/4 with the Z400. I know the Z400 has DOHC and the engine will obvioulsy be heavier but its also heavy everywhere else as well from bolt sizes to casting thickness. All the frame brackets and made of thicker material and there's a lot more of them (something like 25 in total).  It is a very interesting bike to work on though especially with it being Japanesse and comparing it to a Honda as opposed to my Jota, now THAT really does have some serious castings and weight to it

Thank you all for the help and advice so far.

[taysidedragon]

Dave, any supplier of metric fasteners will list them by thread size and pitch. Then different head types, sizes and lengths.

Most hex heads are a standard size, but small heads are used quite a lot on motorcycles. Either for access or just a 'special fastener because they can.

A steel rule, vernier caliper and a pitch gauge are workshop essentials to work on these bikes!

ps. People like Probolt do a little measuring gauge with holes and pitch gauges for working out what you need if that is easier. 👍
https://www.pro-bolt.com/progauge-bolt-measuring-tool/

[AndyD]

Dave,
No problem.
Do you know which fiche is the best for your bike - from the 3 pictured it shows 1980 as J1 and 1981 as J2?

Cheers,
Andy

[Laverda Dave]

Andy,

The bike is a 1981 model so it's a J1. I think the only difference between them was the front brakes were changed on the J2 onwards and the paint colours were constantly changed as they all were back then!
Thanks for your help with this.

[AndyD]

Dave,
Good news - the scanner and PC fired up despite the cold garage and I managed to scan the full fiche in reasonably quickly.
The file is just about 10mb total - can email across if you let me know address etc.
Quality varies hugely on the scans of these old fiches but if any important bits aren't legible on any pages let me know and I can check if it's clearer on one of the other fiches.
Cheers,
Andy

[Laverda Dave]

Although things appear to be a bit quiet with the restoration and I haven’t posted for a while a lot has actually been happening behind the scenes!

The frame has now been blasted and powder coated by Microblast in Windsor (they advertise in Classic Bike) and its due back with me on Monday. All the zinc I sent off to Chingford Tec on the recommendation of my usual plater who is currently off sick with claw hand (a nasty affliction to get if you are a polisher). I am due to get these back on Monday as well. The outer engine cases have been polished although not to a mirror shine as I want to keep the bike ‘stock’ looking.
I have spent the last three days hand sanding the rims and spoke edges of the wheels with wet and dry to remove the corrosion from the alloy but without rubbing off any of the surrounding black wheel paint. To say it’s been laborious is an understatement! 80, 180, 240 and 400 grades used in succession. Removing the old tyres was a nightmare, being the originals and 40 years old and after being stored in a shed with no air inside them left the tyres vulcanised to the rims, I could not break the seal no matter how I tried. In the end I had to cut the tyres with a hacksaw to allow me to get inside and prise them off! Still, the wheels are nearly done now and they are starting to look good.

I have ordered a set of Bridgestone BT45 tyres from HGB as they look suitably old school and will be getting these fitted on Monday as well. Once the tyres are on I will give the alloy a final polish with Solvol. With regards to the wheel paint, the Kawasaki applied black paint has been applied to the rough castings of the wheels and the paint is therefore flat. I have cleaned the paint with engine cleaner to get the grime off but I’m not sure what to do to bring the paint back to a nice black finish, I tried car wax but that just dries white as the casting is so rough below the paint finish. Does anyone have any ideas how to make the black paint stand out, I was going to try furniture polish as it contains silicon and doesn’t need rubbing off? Suggestions welcome if anyone has any  .

Piki (Redice on here) is making some new decals for the tank and tail piece after I managed to get a small piece of the original off using a hair drier and brute force. Kent 400 is going to refurbish the speedo and rev counter as the paint on those has corroded and I don’t fancy trying to separate the top and lower sections without the proper tools and know-how.

Hopefully I can get to work on the front forks over the weekend, like everything else they are full of accumulated grime. I drained the fork oil out yesterday, it was rancid!

Thanks to Andy D on here for scanning and sending me the parts list. I was able to order all the spare engine and frame parts I needed from Z-Power quoting the original part numbers, this made life really easy and took the guesswork out of ordering parts that may not be correct.

Unfortunately the proposed repaint of the tank, mudguard tail piece and side panels will now blow the budget, I’m about £250 over my original estimate (made before I undid a single nut). I think it was a bit of a risk just to get the tank and front mudguard painted without showing up the rest of the paint and especially as it’s a metallic colour, Kawasaki Grand Prix Silver. The BIL is pretty relaxed about it though and agrees it’s better to do a complete job so I’ll crack on for now.

In the meantime and when it gets dark in the evenings, I am busy completing the NOVA and writing a letter of explanation to HMRC as to why no import tax was paid 40 years ago when the bike arrived in the UK from Guernsey. I spoke to a very helpful lady at HMRC who advised me exactly what to do and why I should write a letter of explanation. I normally dread calling HMRC but on this occasion it was a real pleasure.

I’ll post some progress photos next week once the frame is back.

[K2-K6]

Sounds like good progress Dave,  and quite a fair amount of work for you.

Black paint on wheels,  I use things like this on black finish surfaces of anything thats not polished paint.

https://www.ebay.co.uk/itm/AUTOSMART-HIGH-STYLE-TYRE-SHINE-SILICONE-DRESSING-VALET-500ML-BOTTLE-TRADE-USE/283584527221?chn=ps&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&itemid=283584527221&targetid=1139674279347&device=t&mktype=pla&googleloc=1006886&campaignid=12125451284&mkgroupid=120711383910&rlsatarget=pla-1139674279347&abcId=9300480&merchantid=113623010&gclid=EAIaIQobChMI_uSAnLGI7wIVkgCLCh1iCwW5EAQYDSABEgLw6PD_BwE&pageci=22da20d6-5473-4f15-8f61-28332dad94f4&redirect=mobile

If you have polish white residue on the black you can use a stiff bristle brush with this to get it in the nooks and crannies.

[Laverda Dave]

Thanks Nigel. I have a bottle of tyre shine in the garage that is silicon based so I'll give it a go. I used it on the MX5 to dress it up before we sold it, never thought of using it on anything other than car tyres so will give it a go.

[McCabe-Thiele (Ted)]

Interesting restoration project, when I owned a Suzuki 750GS  I was very disappointed in how rusty everything steel became. All the handle bar fittings etc went rusty. Clips springs cable ends you name it and it rusted. Bought it as a part exchange against a private car sale. Sold it after 3 months of summer use - put me off the brand.

[Laverda Dave]

At last some progress I can actually see!
Unwrapped the frame in the garden today and gave it a clean to remove any blasting grit that may be lurking. I'm very impressed with the finish, no runs, blobs etc anywhere. I placed old bolts in any threads as advised by Alan (MCITD) and this saved a lot of time. Microblast in Windsor get my recommendation, this is the third frame they have blasted and coated for me over the last 5 years. This one with everything included and 30 odd brackets was £280.
I fitted the hardest part first, the main stand and spring, luckily I placed washers between the spring coils before taking it off so another lesson learnt the hard way previously put into practice!
Next up was the lower and upper yoke and ball bearings. When I stripped the bike there were 19 upper and lower ball bearings but the parts list specifies 20 lower? Anyway I put 20 back despite only 19 coming out (and this bike has never been apart) maybe someone couldn't count on the Kawasaki production line (and that will explain something else I found during the strip down but that is for another day!).
Whilst all the above was going on the main loom was in the dishwasher. This is now hanging up to dry.
Next up will be the forks and the wheels that I spent three days rubbing down and cleaning.
This is the part of a restoration I like, when you can see a result for the hard work.

[K2-K6]

Looks that they've done a nice job there Dave.

Like the sheep in the background too 

Also think the cast wheels on these are some of the best looking of the manufacturer kit of that era,  believe they are Morris mag copies.

[AshimotoK0]

Looks brilliant Dave ..that's going to be one rare bike when finished with such minuscule mileage.

What are your plans for the exhaust system. On the 300 mile CX500 I got from, a very wet shed,  it was heartbreaking to see both silencers totally rotted out at one end but the other end being so clean inside that there was hardly a mark on the original grey internal coating. They are pretty thick walls on the CX silencers too.

If this is any good ..  if it is I can't see why DK have such a low price on it. also just noticed they have TWO R/H ones listed ?

https://www.ebay.co.uk/itm/Kawasaki-Z400-J-Z550-B-1980-1981-Right-Exhaust-Outer-Downpipe-Collector-Can/313346016012?hash=item48f4e0c30c:g:Xm8AAOSw2slf2kAg

[Laverda Dave]

Funnily enough Ash it was the exhausts that were the cause of the restoration! The BIL had the original pipes replated as they had rust spots over them. When he paid his £600 🥴 to get them back for me to fit they really showed up the rest of the bike as in they no longer matched the rust on the tank, the paint flaking off the engine  and the corroded wheels. It was after this he agreed to the restoration. So....the exhausts are now perfect and the rest of the bike is being restored around them, how unusual is that, normally genuine exhausts are the one item that will hold a rebuild up due to cost and rarity! So far I've had to buy two non original bolts and an exhaust collar that went AWOL at the platers.