Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)

Nebr_Rex

Member
I'm still working on my camshafts. One for a KZ440 and 2 for a KZ400.
One for the KZ400 is going to receive some more weld build up. It is going
to get more duration added.
A member on KZRider needed some slots milled for adjustable sprockets.
Nobody makes them for the KZ/GPz750. So I offered my services and machined
a set for him along with another set and one for a KZ440. The extras I put up on
evil-bay to see if anyone is interested.
Here are some pics....


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Nebr_Rex

Member
The above pic is a cam for a stock bore early KZ400 engine I'm planning on.
It actually has over .100 more metal on the nose than needed.
It will be an experiment to see how much power 400cc can produce, inexpensively.
The other two cams are roughed in, ready to start fine tuning.


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Nebr_Rex

Member
It has been a long time since I last posted. Some other projects and life in general have had me occupied most of the time. I have developed a way to grind cams for my KZ400/440 engines. The tooling needs one more modification to be fully operational. Cam profiles can be inked out on paper and then transferred and indexed to a master cam. The good portion of the time has been use to come up with an inexpensive profile for both the early and late head designs. This means no welding. just a reduction of the base circle. Because of the early heads valve adjustment design this limits the amount to be removed before it is out of the adjustment range. I have managed to get a little more lift, duration and advance of the centerline, compared to published cam specs. This is only on the intake. I have left the exhaust alone because of the size of the valve and port in relation to the intake. The ports on both heads are almost identical in size. Percentage of the exhaust to intake port and valve size is usually 77% to 83%. Early and late heads are 94% and 89% respectively. Because of the super long opening and closing ramps, 70* vs. 30*, I am considering grinding the exhaust also. The cams I have put a degree wheel to are not close to the factory specs. Other grinds are being indexed by degrees and lift.

Here are pics of a welded cam compared to a stock unit.


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Nebr_Rex

Member
No need to, the welded area is harder than the base metal.
That is why I had to make the tooling to start with.
A file would not touch the weld but leave a mark on the base metal.


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JoshMcMadMac

New Member
Nebr-Rex, I have seen your posts on the KZ forum pointing over here. I have a question you might be able to answer:
Can an 81-82 440 head be used on a 78 KZ400 without too much hassle?
 

Nebr_Rex

Member
Nebr-Rex, I have seen your posts on the KZ forum pointing over here. I have a question you might be able to answer:
Can an 81-82 440 head be used on a 78 KZ400 without too much hassle?
To put it simply, if it looks the same it is the same.
Looking at the heads from the side just above the spark plug. The early KZ400 will have a rectangular cover with a screw head in the center. The late KZ400/440 head will have 2 bolt heads. The late KZ440 and KZ440 heads are the same. 1978 was a transition year some had the old style engine and some received the new engine


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JoshMcMadMac

New Member
To put it simply, if it looks the same it is the same.
Looking at the heads from the side just above the spark plug. The early KZ400 will have a rectangular cover with a screw head in the center. The late KZ400/440 head will have 2 bolt heads. The late KZ440 and KZ440 heads are the same. 1978 was a transition year some had the old style engine and some received the new engine
Wow, it's really that simple? If I have a late '78 400, I can literally bolt in an 81-82 440 head?
 
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