Z1B Mid-Summer Refresh

So over the past few years I've noticed two things:

-The stator grommet had developed a slow oil drip/leak

-The oil light would stay on during hot starts until I revved the bike up past 3k rpm.


After replacing the oil pressure sensor and re-routing the oil cooler lines so the cooler wouldn't drain the oil on shut-down, the problem persisted.  The next logical issue is that the original oil pump is worn out and when the oil is hot, has a hard time building pressure.


When I saw that tariffs on Japan were on temporary hold, I placed an order with PAMS (Plus Alpha Mechatronics Service) in Japan.  They're the same shop I got the ignition from last year.  Absolutely fantastic site with an amazing R&D effort into old Z/KZ bikes as well as Nissan Z's.  They actually just released a new performance head for Z/KZ engines.


Here's a google translate link to their shop update page.  Really awesome tech articles.

PAMS Japan Diary (Translated)

https://www-pams--japan-com.translate.goog/diary/?_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp

Anyways,  I hadn't had a chance to ride the bike for about two weeks and walked into the garage to see this:





I guess I can't put off the repairs any longer.

Here's the accumulated parts for the mid-summer refresh:





We have a vapor blasted oil pan from Johnnys Vintage, a new Stator from Ricks Electrics, an oil filter with magnet from PAMS, an upgraded oil pump from PAMS and a viton stator grommet from PAMS.

 

The oil filter is pretty fancy:







The oil pump is new manufacture with 13% greater oil volume flow and a pressure release valve (to prevent pump damage before the oil gets up to temp)

and the Viton Stator Grommet.  This one will not swell and leak when exposed to gasoline.





I had purchased the ricks stator because the last time I did the stator grommet, I wasn't happy with where I cut the wires on the stator.  The stator from ricks comes with a grommet attached however these wires are about 2x the diameter of the stock stator wires and are a really really tight fit through that stock grommet.  I figure I'll use the one that came with the ricks stator and save the viton one for if/when the ricks one starts to leak.


Beefy wires:






 

Beginning work with draining the oil, the magnetic drain plug didn't have much debris:





After draining the oil, I wheeled the bike into the house to escape the heat:





Then I pulled the oil pan.  One of the reasons I picked up a new one is the existence of repair welds on the original one.  you can see them on both the outside and inside of the pan.  There wasn't much debris in the bottom of the pan either thankfully.

Then I was able to pull the oil pump and inspect the screen:





Then I had to swap the drive gear over to the new pump.  I pulled out my Z1 documentation binder to reference the translated instructions I had printed.







I want to pull apart the old pump to see what the gear clearances are and see how far out of spec they are, but he JIS screws are huge and incredibly tight.  I need a bigger JIS screwdriver and a soft jaw vice.


Cleaning off the gaskets from the bottom of the engine was a nightmare. I ended up picking up a carbide gasket scraper and being as gentle and careful as possible.  Eventually I got all the material off.  I plan on just running the gasket and no yama/honda/kawa-bond, but if there's a leak or weep, I may change my mind.





Installing the pump wasn't hard, except for the constant oil drip from it after I primed it with oil as per the instructions.  Ensuring the dowels are in the appropriate spots, installing the new o-ring, and properly torquing the bolts was pretty straightforward.  I had cleaned all the screws for the oil pan in simple green, cleaned the threads, and sprayed out all the holes with brake cleaner.  I also made sure to install the new oil filter-pan o-ring.





Tomorrow I'll torque the oil pan bolts down and get to replacing the stator.

Pulled the stator cover today... part of the neutral switch came with it.



I was able to get this part unscrewed with some needlenose pliers:


 
I ordered a new one, though it was revised to be a bullet/push on connector rather than a screw on so I'll need to change the connector on the harness.  Should be here by the mid-next week. Here you can see the end-state of my previous stator grommet replacement and wiring job... I wasn't happy with it when I did it, and I'm not happy with it now.  Hence the new stator.

Lots of fancy there. Do they explain why the need for the "oil pressure" relief? These are roller engines not plain bearing and preference volume over pressure.

asphalt900 wrote:

Lots of fancy there. Do they explain why the need for the "oil pressure" relief? These are roller engines not plain bearing and preference volume over pressure.



 

From the PAMS site:

https://www-pams--japan-com.translate.goog/diary/?p=22224&_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp

"By the way, this type of relief valve is installed on the pump body only for the GPz1100. The opening pressure of this relief valve is 4.4 to 6.0 kg/cm2.
 
When that pressure is reached at the outlet of the pump, it releases oil into the oil pan so that no more oil pressure is applied to the oil line after the pump.
However, in reality, once the engine has finished warming up and the engine temperature reaches the appropriate temperature of around 90°C, the oil pressure of the Z series does not reach that level due to the structure of the crankshaft.
The reason why such a relief valve is installed is that the viscosity of the oil is very high from the time the engine is started until it warms up to a certain extent, which puts a heavy burden on the oil pump rotated by the crankshaft and prevents excessive oil pressure from being applied to the oil line.

Incidentally, engine oil heats up very slowly compared to the cylinder head of an air-cooled engine or the coolant of a water-cooled engine.

In winter, if the vehicle is equipped with a large aftermarket oil cooler, it is not uncommon for a tuned Z series engine to take more than 30 minutes to reach the appropriate temperature in the city. In that case, the oil viscosity would remain high for a long time, and even though the engine would try to turn, the pump would be put under a lot of strain, causing increased friction and power loss. Therefore, especially in the GPz, where the original oil cooler has been enlarged to deliver the best performance from the Z series, it seems that a larger oil cooler was adopted to achieve a balance from when the engine is cold until the engine is finished warming up."

 

Got it! Here's some additional info if it helps. Those plastic Neutral switches, they crack even on the NOS shelf! An alternative, if you can find one is the 13151-018 metal version. Identical to the plastic one, still retains the original "forked" connector with Phillips head screw. They were used on the Kawasaki F11 250's. And while you're in there fiddling, look at that bypass oil switch. They refined them thru the years, drilling a relief hole in the plate. They are datecoded by the way, last photo, unless replaced.        

I recently changed out my oil pump (Z1B) because I had a whine in the engine.  The pump face plate showed wear marks where the gear was rubbing.  I think it was the original pump but couldn't verify that.  I should have taken it to a Kawi dealer and asked for warranty!

asphalt900 wrote:

Lots of fancy there. Do they explain why the need for the "oil pressure" relief? These are roller engines not plain bearing and preference volume over pressure.

The original Zed engines have an oil pressure bypass valve in the roof of the oil filter housing to relieve excess pressure build up and damage to the oil filter when cold.
The later 998/1089 J/GPZ engines do not have this so they fitted a relief valve to the oil pump.
When fitting a J/GPZ pump to an early 903/1015 engine the relief valve on the pump needs removing and a blanking plug fitted.
The same goes when fitting the Pams pump.

Ha, you beat me to it Zed! I was going to mention the singular ball/spring and hardware but didn't.