Camshaft Bearing seizure!! 1979 KZ1000 A3A, MKII

HELP!  Recent ground-up rebuild including all new cam bearings (amongst a host of other parts too numerous to list for this post). Upon first engine start, engine ran for about 40 seconds before seizing a camshaft bearing (#1 Exhaust position). Suspected poor oil passage cleaning on my part - left over swarf???  Removed head and super-cleaned all passages.  Put it back together with new bearing and fired up again.  Same response only now on the #4 Exhaust position.  Getting tired of this!  Aluminum from bearings was melted to cam on both times.  On the last time, the bearing spun and did minor damage to the head.  Appears fixable, with enough meat to support a new bearing.  I've bean able to clean the alum from the camshaft's bearing surfaces.  I'm hesitant to reinstall as I surely don't want to repeat.  Never experienced anything like this before.
1.  Anybody else had similar experience?
2. I've installed a manual camchain tensioner as part of the rebuild.  I'm pretty sure it's not too tight (I've successfully installed several of them over the past 35+ years with no problems)  Truthfully, I'm starting to doubt myself on this one!  Thoughts? Your adjustment advice?
3. Entire camchain circuit has liska steel rollers and HD Tsubaki chain.
4.  I've removed the oil pan and am taking another look at the pump to ensure no obstructions.  I know these engines thrive on volumetric flow more than on higher pressure.  BUT - they need the most pressure at the plain bearings of the camshafts. All other bearings in the engine are roller / ball types.
5.  Haven't put a pressure gauge on it.  Both times, I've kicked the engine over with spark plugs removed until the oil pressure warning light went out.  Usually a good indication of proper pressure/flow. Then reinstalled plugs and fired it up.
A  
B   
C   
D   
E   
F  After about 8 months, looking pretty good.  Now to get it running!!!


Thanks in advance for your indulgence and input!
Bob F.

 

Did you use any type of assembly
lube, or just flood it with engine oil?  Not sure if it matters but would be good to know.

Later, Doug

Where did you get the bearings?

Those look like aftermarket bearings (the OE ones have a chamfer around the oil hole) lot's of guys on here have had problems with these. Did you plastigauge to check the clearance ?
OEM aren't cheap but probably less than multiple sets of aftermarket 

It looks like you have used cheap pattern shells of which most are known have poor tolerances and bearing material which causes this issue .
Get rid of them and fit GENUINE..
Also have you had the head skimmed by any chance ?
 

You may be onto something....  feeling sheepish now!!
I flooded engine and cams with oil.  Used hypo grease for assembly.  20w50 oil in the crankcase.

Some of my best educational moments have also been the most expensive....
TY for your input!!

 

Aftermarket from Japan.  After reading the other comments, I'm of the impression you all are on to something.  At least that will be a relatively simple fix.  Along with better assembly lube.  Will get dedicated Camshaft assembly lube from Napa later today.  That plus OEM (ouch$$) bearings and we'll see how it goes.

Thank you!!

As Wookie58 said also......  Thank you for the info.  Will be obtaining some OEM.

Confirmed!  Got some sh*tty bearings.  Pics below for comparison. 
Once cleaned up, I think there is enough meat on the head to support a proper OEM bearing with sufficient oil supply.  No damage to the bearing cap.  Can't afford to toss/rebuild the head for the amount of damage incurred.  Don't plan on racing around too much on this one.  Will mostly be a show-off bike at local meets, 'gentlemanly' riding through the foothills, etc.

To answer some predictable questions - I did not plasti-gauge the bearings with cams in place.  The cams spun very smoothly on the bench with new (junk) aftermarket bearings in place, and no valves in the head.  No indication of any issues until engine completed and fired up.

Aftermarket on the left.  OEM on right.  Chamfer easily visible on OEM

Same.  Note bi-metal layers in the OEM.  One layer of aluminum only in aftermarket


OEM has production/manufacturer and size stamped on the back side.


nothing on back of aftermarket.


Much thanks to all!  Will post when running..

From Zed...
Also have you had the head skimmed by any chance ?

Head not skimmed. Checked okay for flat when apart, prior to rebuild.  
Tks!

No eBay APP ID and/or Cert ID defined in Kunena configurationSee attached ebay item, #165800038169. "Kawasaki 13034-030 Z1 K1100 KZ1000 KZ900 Camshaft Bushing Set of 8 NEW Genuine"
Appears to be the right bearings.
Y/N ?

No eBay APP ID and/or Cert ID defined in Kunena configuration

Bobf wrote:

See attached ebay item, #165800038169. "Kawasaki 13034-030 Z1 K1100 KZ1000 KZ900 Camshaft Bushing Set of 8 NEW Genuine"
Appears to be the right bearings.
Y/N ?

The shells are the same for ALL Z1/Z9/Z1000/Z1100,GPZ1100 air cooled engines.
There is only one size which is STD and any difference in the number/letter code on them just denotes batch numbers and manufacture dates.