Z1 Timing Advancer ATU . ...When did it change??

[timyoungman]

I've been checking on the CSMNL web site listed below.

According to the diagrams on CSMNL the Advance /Retard on the 72/73 Z1 is exactly the same as those used on Z1a Z1b, Z900 A4 and Z1000 a/b ....Kawasaki product number: 21148010

I then checked my Z1 engine and it has the same ATU fitted as that fitted on my Z900A4. (The later type ATU stamped 005 )


Here is a picture of the ATU that came fitted to my early Z1 engine.... I haven't touched this since I got the bike and you can see from the rust that it's not moved in years. The TIMING MARK on this is the later type "T" at 20 degree BTDC

fitted to Z1E 14334

Tims ATU.jpg (89.61 KiB) Viewed 2441 times

Inline image


Then I looked at a Web Forum and found the following pictures which shows a DIFFERENT ATU for the early Z1 at with the TIMING MARK at 5 degree BTDC (I am guess the FIRING marks are in the same position ??)

advancerstylesfmarks-2.jpg (142.85 KiB) Viewed 2441 times

So.

Has someone switched the ATU on my early engine ( Z1E14334)

OR

Did Kawasaki change the ATU mid-way through 1973 production ??

I'm a bit confused by the whole thing.

As far as I know my engine ran fine with the later ATU, so should I just stick with it ...I don't want bent valves,

Any info/comments appreciated

[Pigford]

You will not get bent valves by using incorrect ATU type/year, just a bit of timing error. Always set cams using a positive stop thru' the plughole to find TDC!

As for ignition timing, a few degrees here and there won't be too critical - but agree with your comments on varying ATU's.

[Philippe]

Hi Tim
the ignition advancer was changed from number Z1F 32866 (a Z1A frame number).
It was changed to improve the low RPM response.
This and a lot more of information can be obtained in John Brooks' book "Kawasaki Z1 & Z2 1972-73 restorer's parts book". A must have item!
GrtZ
Philippe

[timyoungman]

Thanks for the info.

Philippe, Does this mean someone just fitted a later ATU to my engine then??

Thanks again.

[Philippe]

Hi Tim
yes that's possible. The reason why? No idea, maybe it was damaged, maybe the springs got weak, maybe...
As I always say: what happened with bikes during the past decades? It's hard to say if a 40+ years old bike has all it's original parts... you can only say that if you bought the bike when it was new and you still own it. In most of the cases these bikes had several owners and one owner changed this , another changed that...until it gets to you and than you try to figure out which part is original and which isn't.
It's like solving a puzzle with a lot of parts missing or with pieces from other puzzles added to it. You need correct information and the best way to find that information is in books or at forums written by people who know what they're doing and talking about.
It's a fascinating world...discover it, go for it!
GrtZ
Philippe

[timyoungman]

Thanks very much. I hope to have the engine done soon. Not enough hours in the day !!! :