1977 kz650 head with exhaust gas recirculation?

this is the deal . still working on a freinds 77 650 , he says head was changed by PO for drag race purposes but doesn't know to what year or displacement . i've searched parts fiches for somthing similar but still nothing . this head has 4 holes on top ,same surface as the bolts that secure cam cover . they are in the sparkplug area on exhastcam side . PO had bolts and jbweld jambed in there , but there's no threads inside , got them clear and shot some air in and it came out the exhaust port on some but not all , so , anybody know what these are for , and what kind of head this might be ????????

The Covers were to house reed valve plates as well. It is all part of a fresh air injection system, to add fresh air into the exhaust to help burn the excess gasses. Pollution control. There are block off plates available for several of the sizes, not sure which size the 650 is. They would still have the reed valves in place then the block off plate covering it. Some have blocked the port that goes down into the Exhaust with a plug, I believe you can first thread the hole and then screw in a plug. The missing threads, well 2 of the 4 bolts are long, they go right through the valve cover, down to the head surface. The other 2 go into the valve cover, that's per each side.
If you look at any of the parts diagrams they will show the set up for the USA model bikes. EPA you know.

thanx motor head, no reed valves on camcover . these holes go down into the head itself towards the exaust valve area and angled towards the center of the piston , they are flush with the head surface and are outside of the camcover . never seen this before, and thought someone knew something i should be concerned about or if this is normal and what i should do , or recognise the description and clue me in as to what its from.

Photos would abviously help out a lot.

Perhaps the original cam cover with reed valves (say a US model subject to EPA regulations) was replaced with another cam cover that didn't have the reed valves (such as from a Canadian model).

This is one way to eliminate the EPA paraphernalia without needing to plug/cap the air intakes, or connect the air intakes, or install aftermarket caps without air intakes.








Some of the parts diagrams on kawasaki.com for example show both style cam covers for a particular model, one with the air intakes (US) and another without (Canadian).

If needed, here's a link for help with navigating the kawasaki.com site and locating info such as parts diagrams, part numbers, models sharing same part, availability, etc.
Click > kzrider.com/index.php?option=com_kunena&...w&catid=13&id=376734

Good Fortune!

sorry bout the no picture thing , camra is dead . thanxs patton , i think after seeing the bottom drawing , the head is newer and the older camcover just dont cover the passage . i was confused in thinking that the passage would supply hot exhaust gasses under pressure out these holes not drawing in air . i feel like an idiot , i just couldn't understand sending exhaust gasses into the cam area . duuu if i only had a brain . thanx fellas

Am thinking the previous owner was correct about plugging the now un-used "clean air injection" (un-threaded) passageways in the later model head. Which the PO seemingly accomplished with bolts and JBWeld.

Some folks fill the passageways with JB Weld, without bolts.

Others, as mentioned by Motor Head, tap the passageways and thread a screw or bolt into them.

Unless the passageways are closed by whatever means, the passage would supply hot exhaust gasses under pressure out these holes...sending exhaust gasses into the cam area where a cam cover without the reed valve design is fitted.

Good Fortune!