Topic: Maui Z1 1973

[MauiK3]

I’ll try that, good idea.

[MauiK3]

Back to these one size bearing shells. I’ve never seen a discussion about what to do if there is a little too much clearance, there are no “plus” sizes. Since the valve springs push the cam up I think the only part that matters much is the upper shell, the lower Is there to fill the gap and set the oil film up.

[Terry in Australia]

Good job Steve, I’ve been following this thread so long, I really want you to succeed, I would (almost) kill to have an original Z1 parked beside my Z1-B hotrod, but there are no “barn find” early Z1’s on this side of the ocean. You might not feel like it right now, but you’re a very lucky man.

[Terry in Australia]

Re: the cam shells, most people look at it the other way, the cam chain pulls the cams down against the bottom shells, so the top one is just the filler until the moment that the valves begin to open. Excessive clearance would cause some additional top end noise, (obviously too much clearance would be catastrophic) but wouldn’t cause the “seizure” you’ve described, if anything excess clearance would guarantee that the cams don’t seize, not that cams seizing in Z1’s is even a thing, in my experience.

[Stev-o]

I certainly wish I could help somehow but this is a head scratcher.

Here's a link to his thread on KZ rider...

https://kzrider.com/forum/11-projects/616295-1973-z1-maui?start=408

[ekpent]

Looks like some good helpers on his thread there.

[craz1]

Looking at that damage to those bearing I keep on going back to contamination. It sure looks like grit has gotten in there to cause damage like that. have you dropped the oil pan and looked very carefully for any grit that may have settled.

[MauiK3]

This motor is been apart and washed very clean, flashlight checked, etc. The oil pan has been free of anything foreign. I wish it were that simple. I'm going to do like Terry suggested. Strip the valves out, put the head back on and turn it to see oil delivery etc. I'm also going to try to determine, again, if these bearing shells are somehow distorting at assembly. I'm really grasping here, this should have been pretty simple to get running. I can't tell you how frustrating this is, these engines aren't and shouldn't be this fussy to get running, many, many have been successful.

[grcamna2]

Steve,I'm 'pulling for you' to find the issue with those camshaft bearings;as you mentioned, "these engines aren't and shouldn't be this fussy to get running".The thing has had a cursed problem caused to it earlier before you received.. it shouldn't be this difficult.
I would consider another head temporarily to diagnose what's causing it,if that's possible?

[PeWe]

No hard particles in the oil around the cams?

[grcamna2]

No hard particles in the oil around the cams?

Would be interesting to get an automobile battery with jumpers,then isolate the cam chain from the lower crank sprocket,no plugs and no camshafts.
Then hook-up some type of rubber tubes to each camshaft bearing journal oil output hole in the head and attach each one to it's own separate white cup;then give it a long crank-over(a few minutes,intermittently?)and see what you find in each one of those white paper coffee cups?

[craz1]

The problem with beads is one grain can do the damage you see. There could be beads packed in just behind those plugs. I do see you made covers to help protect the head. Not sure if I saw any plugs in the outer cylinder stud holes for that head. They need to be plugged before blasting. Im sure you saw that when you removed those covers you still had beads all over. If you didn't block any of those cam lubricating holes there is no telling where beads migrated to. I see you also used a fine bead.

[grcamna2]

The problem with beads is one grain can do the damage you see. There could be beads packed in just behind those plugs. I do see you made covers to help protect the head. Not sure if I saw any plugs in the outer cylinder stud holes for that head. They need to be plugged before blasting. Im sure you saw that when you removed those covers you still had beads all over. If you didn't block any of those cam lubricating holes there is no telling where beads migrated to. I see you also used a fine bead.

Could removing the head then a serious flush of all the oil passages fix this ?

[craz1]

One would think so but many engines have been ruined through dry bead blasting. Im just expressing my thoughts on what I see. The way I see it is if those cams were binding ever so slightly I would expect that engine to run for quite some time (especially if he used assembly lube) before the expansion would start to slow things down and finally lock up,  things would be very hot and you might see some discoloration on the cam. Sounds like the engine locks up only after several minutes and those bearings look horrible.

[MauiK3]

All openings had a tape seal and then the wood cover which was also sealed with tape. There was a lot of soaking and water, air, simple green water, air, sloshing, etc work.
I’ve got the cams out. Before I remove the head to take the valves out I’m going to do some air blowing from the plug on the right side to see where air comes out. Then I’ll remove the head, take the valves out and put it back on with the cams and try to turn it with the starter to see oil flow. (No plugs)
Happily I think the cam will clean up and still be in spec.
I’m also going to count cam chain links just for grins.
I’m also going to get a gauge for oil pressure. It’s only rated as a two pound system.

[Terry in Australia]

Yep, My Z1-B has a 20 psi gauge on it Steve and I’m always surprised at how low the oil pressure is, but some folks think that low pressure equals low volume, which is incorrect. Kawasaki and Suzuki GS engines (because they stole the engine design from Kawasaki) run low pressure, high volume oiling systems, so you’re looking for a good flow of oil, not a dribble.

[MauiK3]

Head is off, gauge is on the way for later use.
Before I took the head off I applied air pressure to the plug opening near the points. Since there are 8 holes at the cam bearings I applied some light assembly grease over each hole (cams out). I puffed air pressure and it popped each little grease blob at each hole.
Removed the head and there are signs of oil at the studs, that’s good.
Took the valves out of the head and I’m looking for size, alignment etc type problems. I’m assembling a shell, torquing the cap down and using a snap gauge to check for ID and roundness, takes time. Next I’ll put cams in and check again for binding and if there is I’ll try to figure out why. I don’t think it’s warped but I’ll check that too, I can use my table saw top, it’s pretty flat.

I’d like to somehow check pump output. I’ll take it out and devise a drill drive setup in a bucket.

[Terry in Australia]

Head is off, gauge is on the way for later use.
Before I took the head off I applied air pressure to the plug opening near the points. Since there are 8 holes at the cam bearings I applied some light assembly grease over each hole (cams out). I puffed air pressure and it popped each little grease blob at each hole.
Removed the head and there are signs of oil at the studs, that’s good.
Took the valves out of the head and I’m looking for size, alignment etc type problems. I’m assembling a shell, torquing the cap down and using a snap gauge to check for ID and roundness, takes time. Next I’ll put cams in and check again for binding and if there is I’ll try to figure out why. I don’t think it’s warped but I’ll check that too, I can use my table saw top, it’s pretty flat.

I’d like to somehow check pump output. I’ll take it out and devise a drill drive setup in a bucket.

Good job Steve, I think if you put your head back on less valves, drop the cams back in (timed) with the oil pressure gauge attached and crank the engine on a good battery for a couple of minutes, that will give you a more honest idea of how well your oil pump is pumping, or not.

Obviously not as good as it would with the engine running because the starter motor won't crank it over as fast as if it was if it was idling, but it should give you a good indication. I'd love to see a short video of it all working, if you've got a cell phone with a camera?

[RAFster122s]

Don't get too carried away with testing the output if using the starter. They aren't designed to run that long continuously and you can cook a starter or cause it to fail as the windings will get tattoo burning hot from running for very long.
I wouldn't do it beyond a couple minutes at most and less if I could. Since it is a high volume pump you should be getting a pretty good idea of the volume coming out in a minute.
Any way to rig up you drive to pull the pump out of the bike to test volume ran off a different source? Anyone know what rpm the pump is driven at in operation?
The output of the pump is one part of the equation but as you already have pointed out looking at and comparing the volume for each output in the cam caps for those bearings  must be considered as well.
The oil pressure normally we see on gauges is measured relative to crank bearings...

Hope you can figure out what has caused this problem as it is both expensive and maddening-ly frustrating to have to go through this...

[MauiK3]

Still working through things. I only found some damaged bearing shell material around the cam area. I’m going to try to figure out how fast the pump turns and try to rig something up in a bucket.
Extreme times……extreme measures

[Terry in Australia]

You can test it all you like outside of the engine in a bucket, with a drill etc, but that will only tell you if your pump is working outside of your engine, you need to test it in your engine to see if there is a restriction caused by blasting grit, old bearing material, old gasket particles, old sealant, etc.

Using the starter may not be ideal (but Z1 starters are notoriously rubbish and CB750 starters bolt right in) but if used only for a few seconds at a time with no valves or spark plugs in the head, and therefore no compression to fight against, it shouldn’t hurt anything, and the benefit of doing this is you can actually see how much oil is moving up to your head, and if all oil passages are clear, if your cams are straight, and hopefully, what’s causing this highly unusual issue.

[MauiK3]

Agreed
Just to satisfy my curiosity I put the pump in a bucket with engine oil, spun it by running a buffing wheel against the gear and it pumped oil, which I expected because it turns the oil light out. Messy
Still looking, working up to the no valves, no plugs crank over.

[Terry in Australia]

Good job Steve, I wish I was there with you, looking over your shoulder!

[PeWe]

We could be a biker gang from Sohc forum.
Drinking beers/drinks and chatting about various ideas.
Hopefully creap distance to a nearby hotel

[MauiK3]

The hotels near here would come get you with their Suburbans or Teslas. I'm on the the south side of the island about 1/2 mile from the ocean that is lined with hotels and condos. Just south of me starts the area called Wailea and then Makena where all the really expensive hotels are and homes of part timers like Jeff Bezos (Amazon), Peter Thiel (formerly of PayPal), Paul Simon, Steven Tyler (Aerosmith) etc. You'd be amazed at their property tax bills, more each quarter than I make in a year.

Diving back in today to look at more unlikely reasons for my problem.