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KZ1000 Cylinder Head Swapping
- beefsquasher
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I bought a whole head on eBay because as long as I'm in there I might as well replace the whole head (broken fins, messed up exhaust stud bosses, ported out wayyyy too big by the previous owner, leaking oil due to gasket surfaces being pried apart by the PO, etc.)
So here's the question: It's a '79 head and everything seems to be the same except that there are 4 ports on the exhaust side of the head, on the spark plug side of the camshaft housing that don't match up with my '77 cam cover and gasket.
I assume these are for emissions/air injection/crankcase ventilation or something else equally worthless. I can't see where they go. Can I drill, tap, and countersink a hole square to the gasket surface into these and then plug them with a small threaded plug, or am I just wasting time?
-Dave
1977 KZ1000 Mutt - 1075, Kenny Harmon Cams .400", RS34, Kerker, Dyna S
1997 Honda XR250R
1977 Yamaha XS360
1972 BMW R60/5
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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- PLUMMEN
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Still recovering,some days are better than others.
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- beefsquasher
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I'm just going to swap over the Andrews 2x cams and add a set of APE cam sprockets appropriate to the 15t crank I have , so I expect no problems there. Should I replace cam bearings? Use the ones from the original head or the new head?
-Dave
1977 KZ1000 Mutt - 1075, Kenny Harmon Cams .400", RS34, Kerker, Dyna S
1997 Honda XR250R
1977 Yamaha XS360
1972 BMW R60/5
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- beefsquasher
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-Dave
1977 KZ1000 Mutt - 1075, Kenny Harmon Cams .400", RS34, Kerker, Dyna S
1997 Honda XR250R
1977 Yamaha XS360
1972 BMW R60/5
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- PLUMMEN
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Still recovering,some days are better than others.
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- beefsquasher
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Going back to the question about plugging the emissions ports - does it make a difference if I plug them at the top (easy) or plug them at the hole in the exhaust port (hard). Thats a pretty big hole in the exhaust port! Is this going to disrupt exhaust flow?
I am planning to mildly port this head (increase bowl volume, blend and smooth casting flaws, blend rear seat ridges, port match).
Once again, am I wasting time, or do I simply have a nice clean, usable '79 head to sell back on eBay?
Also, any porting tips? I have already read many of the existing posts on the subjects and it seems pretty cut-and-dried. Any specific points?
Am I asking enough questions?
-Dave
1977 KZ1000 Mutt - 1075, Kenny Harmon Cams .400", RS34, Kerker, Dyna S
1997 Honda XR250R
1977 Yamaha XS360
1972 BMW R60/5
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- PLUMMEN
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Still recovering,some days are better than others.
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- Jack
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79 KZ 1075 MKll
79 KZ 1500 MKll dragbike
Gone but not forgotten:
3 X 73 Z1's
1 X 74 Z1A
1 X 75 Z1B
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- larrycavan
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I finally have th eBay head apart. Everything looks really good and fresh - valves, guides, seats, bearings, and so on (a few threads need helicoiling - no problem).
Going back to the question about plugging the emissions ports - does it make a difference if I plug them at the top (easy) or plug them at the hole in the exhaust port (hard). Thats a pretty big hole in the exhaust port! Is this going to disrupt exhaust flow?
I am planning to mildly port this head (increase bowl volume, blend and smooth casting flaws, blend rear seat ridges, port match).
Once again, am I wasting time, or do I simply have a nice clean, usable '79 head to sell back on eBay?
Also, any porting tips? I have already read many of the existing posts on the subjects and it seems pretty cut-and-dried. Any specific points?
Am I asking enough questions?
-Dave
Open the throats to 32mm.
When measuring the bowls, take them to 34mm.
Raise the roof 3mm in the guide boss area.
Don't get any low spots in the runners.
Don't make the entrance of the port any larger if you have 26, 28 or 29mm carbs.
Here's how to measure the bowl.
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- PLUMMEN
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yeah that sounds really simple now dont it? run for your lives boys! :woohoo:beefsquasher wrote:
I finally have th eBay head apart. Everything looks really good and fresh - valves, guides, seats, bearings, and so on (a few threads need helicoiling - no problem).
Going back to the question about plugging the emissions ports - does it make a difference if I plug them at the top (easy) or plug them at the hole in the exhaust port (hard). Thats a pretty big hole in the exhaust port! Is this going to disrupt exhaust flow?
I am planning to mildly port this head (increase bowl volume, blend and smooth casting flaws, blend rear seat ridges, port match).
Once again, am I wasting time, or do I simply have a nice clean, usable '79 head to sell back on eBay?
Also, any porting tips? I have already read many of the existing posts on the subjects and it seems pretty cut-and-dried. Any specific points?
Am I asking enough questions?
-Dave
Open the throats to 32mm.
When measuring the bowls, take them to 34mm.
Raise the roof 3mm in the guide boss area.
Don't get any low spots in the runners.
Don't make the entrance of the port any larger if you have 26, 28 or 29mm carbs.
Here's how to measure the bowl.
Still recovering,some days are better than others.
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- beefsquasher
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So the throat is the area just above the valve seat and the bowl is the area farther up around the valve guide?
I'm running 34mm Mikuni RS carbs, if that makes a difference. I know they're too big, but that's what came on the bike so I'm gonna use them.
I got some heavier springs and am clearancing the cam area so that I can drop in some larger cams when I get some more dough together.
Is is worth it to go larger on the cam than my existing Andrews 2x cams (approx .360 lift) with my current setup?
-Dave
1977 KZ1000 Mutt - 1075, Kenny Harmon Cams .400", RS34, Kerker, Dyna S
1997 Honda XR250R
1977 Yamaha XS360
1972 BMW R60/5
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