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Author Topic: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)  (Read 52773 times)

Online Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #90 on: Sep 08, 2013, 19:09:28 »
Done grinding the cam for now. It just needs to be cleaned up to be
checked with a degree wheel. Also did my valves. This method is a
little more accurate than my old Sioux valve grinder. That thing is out
of round about .002 for .004 total. Good enough for old pushrod V8s,
but not small engines. Next is to lap the valves, since the seats are in
great shape. Then I can tear down the top end and install the other
block and Wiseco pistons. And see what the new lobe profile looks like.
And one last thing, there is a Fluke oscilloscope on the way via eBay.

Pics are of the same lobe, before and after getting dressed down on
both ramps. And an exhaust valve.


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Online Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #91 on: Sep 08, 2013, 19:11:44 »
The valve.

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #92 on: Sep 14, 2013, 00:21:06 »
Pics of the old pistons and the new. Head is torqued down and I stared
to degree the cam. With valve lash set at zero on the intake, valve lift is
.358 vs. .288 on the cam.

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #93 on: Sep 16, 2013, 22:21:22 »
Cam is finished. Will post final specs tomorrow.
But valve lift is .350.
Pics of the opening ramp.

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #94 on: Sep 16, 2013, 22:22:51 »
Pics of the closing ramp.

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #95 on: Sep 18, 2013, 02:47:04 »
Cam timing turned out to be

 43/73, 296 dur., 105 c.l., 350 lift intake,        vs. 27/73 stock
 63/39, 282 dur., 102 c.l., 308 lift exhaust.    vs. 70/30 stock

 I still need to open up the slots on the cam gear so I can advance
the timing some more. That way the exhaust will be at 110 c.l.
like the stock setting. And the intake will be at 51/65, 97 c.l..
Which is 21 more overlap, 16 more dur., and the valve closing
5 sooner. Resulting in more cylinder pressure and better breathing
because of valve events and a 10.3/1 compression ratio.

It was time consuming to get equal cam profiles by hand. I only used
a die grinder a couple of times. Otherwise it was a file and emery cloth.
Typical procedure was to remove the rocker box, cam caps, chain, cam.
Remove some metal and reinstall everything. The check the degree
wheel pointer for t.d.c., then valve lash and set up the dial indicator.

.

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #96 on: Sep 28, 2013, 22:53:12 »
The mailman dropped off a package the other day.

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #97 on: Oct 05, 2013, 21:29:25 »
Finished with the cam. Had to trim down the right side base circle.
It had some negative valve clearance by a few thousands. Advanced
the cam one tooth (15.6 ?) ending up with these measurements at
the valve at zero lift. 

Intake      48/65 (stock 27/73)  98.5 l.s.   (113), 293 (280), .350 ( .305?)
Exhaust.  71/28 (stock 70/30) 111.5 l.s. (110), 279 (280), .308, 76 (57) overlap

Summary: intake advanced 14.5, 13 added duration, closes 8 earlier
                    exhaust advanced 1.5, overlap increased 19




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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #98 on: Oct 08, 2013, 00:42:04 »
Fired it up for the first time today. Ran 'alright' up top but lousy down low.
Swamped jet needles, that made an improvement. Then I noticed the head
pipes turned a blueish/purple. Checked the timing mark against the rotor
reluctor alignment. Yep, timing was little retarded. Elongated the holes in
the timing plate by about an 1/8 in. Timing looks real close. Need to
retorque the head before I can check it with a light.


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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #99 on: Oct 17, 2013, 18:30:27 »
Update:
  Welded up some duct work to run filters while I experiment
 with the relocated pickup coils. I used some of that aluminized
exhaust tubing from the auto parts store.The low carbon crap
doesn't weld for shit. Along with some rubber plumbing connectors
from the hardware store. Topped with some K/N filters for a
Triumph. It idles ok and top end sounds good. But just above idle
to about 6k is lean. Jetting is; stock 35 pilot, raise .060 in., idle mixture
screws 3 1/2 turns out and main up from 88 to a DynoJet 130.
Needle is a 2A, same taper as a 1A but starts sooner. And way
smaller then a 10A. Going to try raising the needle some more.
Thought I would throw this out there, maybe it could help someone
else running CV carbs.

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