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Author Topic: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)  (Read 51816 times)

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #200 on: May 13, 2018, 23:03:20 »
    Been busy at work putting in some hours.
Lost some pressure on no. 2 cylinder. Found out why when I disassembled
the top end. The intake valves looked good and the exhaust have carbon build up.
The problem was the sleeve on no. 2 had rust rings about half way down and at the top.
Was able to hone just about all of it out. I was also reminded of why I dislike old
base gaskets. Up next is to reassemble, find true top dead center and install my
degree wheel to take some measurements. Did some math and by removing the
base gasket reduces the volume by 1.7cc and retard cam timing 1*.


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Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #201 on: May 20, 2018, 22:06:05 »
  Top end is back together. Ran a compression test after a quick 1/4 turn from tight lash adjustment.
Right cylinder tested 155 psi and 162 psi for the left. This is without the engine being ran so the parts
can take a set.
  2 more points of interest.
1] The timing mark is not top dead center on this engine.
2] Modified a cam sprocket. If anybody is looking to have one machined just contact me.


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Offline doc_rot

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  • Oh the usual... I bowl, I drive around...
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #202 on: May 21, 2018, 02:23:03 »
Interesting...When I set the ignition on my kz750 twin  I found TDC using a piston stop and the factory TDC mark  was 2  degrees off.

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #203 on: May 21, 2018, 23:25:06 »
To index my degree wheel I had to use a dial indicator. Never paid any attention
to the timing marks before, mainly because they were hiding behind a degree wheel. Looks
it's off 4 or 5 degrees.


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Offline canyoncarver

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #204 on: May 22, 2018, 13:03:11 »
To index my degree wheel I had to use a dial indicator. Never paid any attention
to the timing marks before, mainly because they were hiding behind a degree wheel. Looks
it's off 4 or 5 degrees..

Man, that's surprising that it's off that far.
--

YZF750/1000R The Fly
KZ 750 Twin
ZRX 1100
KZ400 The Rabbit
KLR650, 65 Norton, my never finished shovelhead chopper, an 86' FXR, and an F9 Bighorn
more YZF750R's, more KZ's, a Zephyr750...and the ever unfinished 75' CB550 cafe.
--

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #205 on: May 22, 2018, 23:28:47 »
Man, that's surprising that it's off that far.
And the removal of the base gasket should only account for 1 degree.


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Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #206 on: May 23, 2018, 00:14:39 »
And the removal of the base gasket should only account for 1 degree.


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Scratch that, brain fart, has nothing to do with the altered timing of the cam because of the base gasket removal.


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Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #207 on: May 23, 2018, 21:57:05 »
Installed a dial indicator on no. one intake valve.
Measurements were taken with lash set at 1/4 turn from tight and at zero lift.
Kawasaki measures at zero lash.
Valve opened at 18* BTDC and closed at 73 ABDC. Lift is .308 with lash.
That is 271* duration and 117.5 lobe center. Factory specs say 113* lobe center.
Base gasket removal can account for 1 degree, the rest has to be from chain
stretch and wear. Advancing one tooth will equal 102* lobe center.


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Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #208 on: May 28, 2018, 10:08:08 »
  Set valve lash to zero and duration increased to 276*.
Reset lash to .004 while checking at .040 and .050 valve lift.
At both of those measurements lobe center jumped to 115*
so I'll go with that. Valve lift with zero lash is .317 in..
Duration at .040 is 218*. Compression tested at .004 lash was
150 psi on cylinder 1 and 140 psi on cylinder 2. Advanced the cam 1
tooth, 15.65 degrees. Compression increased to 185 and 167 psi.

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #209 on: Aug 24, 2018, 23:57:18 »
  Picked up some KZ400 parts. I have almost a whole bike. Basically missing the tank, seat, side covers, carbs, tach and headlight.
No title with a 3-74 build date. 2445th bike built with a 2418 engine number. Odometer shows under 7100 miles. Engine has compression.
Going to check engine over with a compression test and then flip the cam sprocket. Plan is to punch it out to 67.5mm, port the head
and some cam work.


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