Topic: Maui Z1 1973

[Terry in Australia]

Can the original tank be repaired mate? I watch a car show ("Graveyard Carz") where they buy and restore cars that you and I wouldn't even think about restoring because they've been smashed beyond repair, or rusted into the ground, but these guys are so good, they can turn a turd into a gem.

Your tank may need to be cut open from underneath and beaten out, but it's probably worth it if you can't find another one. I must check my OEM Z1 tank and see if it's the very rare early Z1 tank, it's only got one dent on it, from where the bike was leaning against the workbench when I was trying to kick start it, no easy feat with the 1100cc big bore kit.

The guy I bought all of my Z1 engine parts from in the US might have some original fasteners? His Ebay name is Oinkjohnson and he's got tons of Z1 parts, he's currently got a listing for Z1/KZ1000 bolts, but I don't know if they are off a Z1 or not? He's a nice guy, I think his name is Brad, maybe you could shoot him a message and see what he's got?

https://www.ebay.com/itm/203523726901?hash=item2f62f59e35:g:R64AAOSw6Ctg7MQq 

[MauiK3]

I’d need to take the tank to some of the usual suspects here for a look see. Then I’d need to find someone that can reproduce the paint. I may do the repop thing and tackle the tank as a separate project. Good idea.
On another note, my new book came in! I need to do some reading homework.
It says there were 4895 Z1’s built in 1972, mine was October, one of 1345 in that month. Amazing.
28,408 were built in 1973.
I’m almost overwhelmed. I’ll really need to balance total stock with what I can actually do.

[Terry in Australia]

I’d need to take the tank to some of the usual suspects here for a look see. Then I’d need to find someone that can reproduce the paint. I may do the repop thing and tackle the tank as a separate project. Good idea.
On another note, my new book came in! I need to do some reading homework.
It says there were 4895 Z1’s built in 1972, mine was October, one of 1345 in that month. Amazing.
28,408 were built in 1973.
I’m almost overwhelmed. I’ll really need to balance total stock with what I can actually do.

Yeah mate, as I've been saying, the 1972 Z1 is rarer, and arguably more sought after than a sandcast CB750. The good thing about the repop tank is that if you do ride it regularly you can just store the "Unotainium" tank once it's been repaired, for when you eventually sell the bike.

[jaytee-nz]

Years ago, I restored a 1976 Z900 (long gone now) so I'm following your build closely Steve.
Came across this Youtube video today that I thought might interest you, if you haven't seen it before.

[Terry in Australia]

That's a great vid, I watched it several times when I was building my Moriwaki 1100cc Z1-B and 1428cc Arias KZ1000 engines last year, and imagined how fast my bikes would go around Daytona.

[MauiK3]

A few update photos.
The chain is pretty stiff, lots of links that don’t straighten out, lots of built up goop.
The starter will need some serious cleaning up, it works though. I’m glad I have my book by Marsden so I can get as much of it right as I can.
Here on Maui I’m faced with the fact that any bike that is ridden here has to contend with our marine environment. My neighbors Harley has lots of corrosion on it.
Without basically altering it I need to give it a chance to not turn back into what I purchased.
I’m definitely going to try to get someone to fix the tank.

[Terry in Australia]

Yep, if it's an O ring chain it's not original anyway, so you're better off buying a new DID(?) 630 non O ring chain for it.

[grcamna2]

Good to see that APE manual cam chain tensioner:foolproof part 

[Terry in Australia]

They are great Bill, I have them on both my Zed (Zee) engines, but not so good on Steve's very rare 1972 Z1, which needs to be completely original. I believe he's since bought the OEM cam chain tensioner.

[grcamna2]

They are great Bill, I have them on both my Zed (Zee) engines, but not so good on Steve's very rare 1972 Z1, which needs to be completely original. I believe he's since bought the OEM cam chain tensioner.

I installed one on my red and black 1983' GS1100ED with a high performance ported 1170 engine which I sold back in the late 90's and I never doubted that the cam chain was going to 'wrap-up'(which is what the stock one might do)if I backed off too fast at high revs.

[Terry in Australia]

Yes mate, and as bikes have become more powerful, cam chain tensioners sh1tting the bed has become much more common. Honda went to gear driven cams in their (magnificent) VFR750's after the "Chocolate Cam" debacle of the earlier VF series bikes, but then cheaped out with the second gen VFR800, went back to cam chains, and guess what? More cam chain failure, just like you say, when backing off from high RPM. Same/same for the VTR1000F "Firestorm", I bought one cheap that had dropped a camchain, and my current one came to me with, guess what? A pair of APE camchain tensioners. I'm not unhappy at all that my two Honda VTR1000R (RC51) SP1's, like my VFR750, have gear driven cams.

[Jeff.Saunders]

do not dispose of the old tank (or any of the original parts).  It is possible to repair that tank.

Greg Walker is an avid Z1 collector.  He's got a staggering collection of early Z1's.  Including two of the prototypes which were not even Z1's, but rather V1's.  Plus he has a press bike (one of a handful issued to the motorcycle magazines in 1972 that have unique VIN numbers) - and then he has a good number of low VIN Z1's.  Including Z1F-00010.  The reason I mention Greg - he's done things to restore parts that I would never have considered - like cutting original 4-4 pipes in half to repair rot from the inside.

In terms of restoring versus getting it to be a nice representation, the value difference is considerable - but really the decision is down to what you want from the bike.  If you plan on riding it, then make it a nice representation - as you'd be totally distraught if you damage a nearly irreplaceable part while riding. 

[MauiK3]

Jeff
Yes, good point.
Right now I've got a cam chain tensioner that is from a later model after not finding an original, it will do for now. I'm saving stuff partly because I'm not sure yet what is original and what isn't. I know the front and rear fenders are not original and they are very corroded. I'm pretty sure the rims are not either. The exhaust will be repop 4-4, the originals are long gone. The handlebar controls are almost certainly repops. This almost demands I make a good representation and then maybe consider searching for parts that are more correct. I'll joy ride it but I won't push it, at my age who needs to take risks! I like the idea of fixing the tank, I'm glad I snagged it. I'm going to shop it around to see if someone wants to tackle it. I'll inspect and repaint the motor.
As far as the motor goes, is there a paint that is a close match to whatever the original coating was? I'm guessing it was a satin finish, not very glossy.
For the frame I want to use POR15 with their chassis black top coat. It's very tough and has that not too shiny finish.

[Jeff.Saunders]

Engine paint is satin black.  Most people I know who restore get the engine parts powder coated.  Not easy to do unless you pull the engine apart.

Some of Greg's Z1's.

[MauiK3]

Nice collection! I wonder what numbers they are.
We have a powder coat shop here, I’ll speak with him. I don’t mind taking the motor apart, I’d like to measure and inspect it all anyway. I imagine it will require thorough plugging of all passages, blocking the flat surfaces, etc.
good info, thank you.

[ekpent]

 I googled "Greg Walker Kawasaki" and read some good stuff he had written about Z1 history etc. and learn more about him.  He made the point in one article about the amount of machines going back to Japan to which I can testify from multiple sources is still going on with a feverish pitch.

[Jeff.Saunders]

No 10 is the second bike in the picture.  I'm not sure of the other numbers - but the first one appears to be a prototype or press bike.  The rear shock appears to be at a more vertical angle than usual.  The prototype and pre-production bikes used a shorter swing arm.

No 10 is one I alerted Greg to in 2007, it took until 2010 for him to finally persuade the owner to part with it.

If you take the engine apart, you will appreciate just how over-engineered those engine are.  There are a couple of weak spots in the design.  Mainly the cam chain, cam chain idler sprockets, tensioner assembly, and top idler assembly wear out within 50k miles.

There's not much you can't get to replace parts - internally aftermarket is often better - but it depends on the part.

If you do pull the engine apart, you may find higher lift cams if the PO went to the trouble of putting a big-bore kit in it.  Good used cams are not too hard to find - although the first two years of the Z1 used hollow cams...  yes - hollow - drilled all the way through the cam to lighten it.  They eventually switched to solid cams.

[RAFster122s]

Godfrey’s Garage does tank work, but be very aware that the tank restoration you are talking about doing is likely some serious coin. Jeff has done many custom hybrid tanks stitching two different tanks together. He is very skilled.
Given the rare nature of the early Z1, the tank would be worth it, if you were selling the bike or selling the restored tank outright. But, you might pass the price of a repop tank in rebuilding the original…

[MauiK3]

Does anyone have a photo of what a Kawasaki fastener looks like? My Honda fasteners have the figure 8 sort of symbol on them.
I don’t think I’ve come across even one so far.
The frustrating part here is what the PO disposed of, I’ll have to get as much as I can but I know I’ll never find it all.

[Terry in Australia]

I've got heaps of Kawasaki bolts here Steve, but I wouldn't know whether they were from a Z1 or KZ1000, GPZ1100 etc, so the only bloke here who'd know would be Jeff. Re: your frustration, you need to balance that with the knowledge that you didn't pay very much for a bike that, if restored properly, is worth more than a sandcast CB750. I wouldn't be too upset if it was me.

[MauiK3]

I have a slip from a local machinist, now retired, who did some work on it in December 2009. I spoke with him and verified the work.
It’s been bored 0.020” over which corresponds to about the 0.5mm first over pistons. I’ll be checking but that makes it about a 917cc engine.
The head was done, valves lapped and the cylinder block was “resurfaced”
This may explain the higher than stock compression I found.
There are receipts from Z1 Enterprises in the same time frame for cam chain tensioner parts, 66.5 mm pistons and associated parts including valve guides and seals.
I don’t think it’s been ridden much since then, I saw it run in about 2012. From what I’ve found, it may never have run well due to old caps on the vacuum ports (the ones on the engine), plug wire ends with high resistance and some other stuff that was overlooked like a plugged slow circuit in one carb.
The inside of the engine should be in pretty good shape (I hope).
I’m going nuts waiting for carb parts so I can start it, I’m trying to figure out compressing a video so I can post it.

[MauiK3]

Terry
You are right, I just need to my best and be happy with it, as I’m sure I will.
I take joy in that I’m going to bring it back from what surely would have been a bad end.

[Terry in Australia]

Terry
You are right, I just need to my best and be happy with it, as I’m sure I will.
I take joy in that I’m going to bring it back from what surely would have been a bad end.

Yeah mate, you've done well, so even if it's never back to "factory" original, it's still a very collectable bike, and I for one am envious. It sounds like the engine has had a recent birthday so probably doesn't need much, if any, work so that's a bonus, you only need to worry about the small jobs that the owner didn't get sorted. I really think you'll end up with a very nice bike when you've finished with it.

[RAFster122s]

Just upload the video to your YouTube account or similar place and then post a link to the video after you set permissions that anyone can view it.

Buying old bolts from Oink and having them replated if needed (they probably do given your high corrosion environment) and then ensure they are chromate conversion coated, clear, yellow,  blue or whatever version Kawa used is going to be your best bet.
Replating fasteners is a lot of work for most of us as there is lots of cleaning and wire brush and light buffing going on for each fastener. It is satisfying work and it is a good skill to have.
We Honda owners are lucky Yamiya carries repro bolts new with the little infinity type symbol as well as the plain head zinc chromate bolts.

[Terry in Australia]

Just upload the video to your YouTube account or similar place and then post a link to the video after you set permissions that anyone can view it.

Buying old bolts from Oink and having them replated if needed (they probably do given your high corrosion environment) and then ensure they are chromate conversion coated, clear, yellow,  blue or whatever version Kawa used is going to be your best bet.
Replating fasteners is a lot of work for most of us as there is lots of cleaning and wire brush and light buffing going on for each fastener. It is satisfying work and it is a good skill to have.
We Honda owners are lucky Yamiya carries repro bolts new with the little infinity type symbol as well as the plain head zinc chromate bolts.

If you go back a page or two David, you'll see that Steve does his own plating. You can buy repro Kawasaki bolts from the same guys who sell the repro tanks etc, but this bike should have as many OEM parts as possible, as it's not your "run of the mill" Z1.