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Author Topic: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)  (Read 50561 times)

Offline teazer

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #10 on: Aug 21, 2012, 02:31:19 »
Interesting project.  Are  you sure about those 34mm carbs?  That's a big carb for smallish 4 stroke cylinder.

Offline Shermanator86

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #11 on: Aug 21, 2012, 08:40:11 »
What gave you the idea I have trouble with intake bolts?
The big carb boots are on purpose.
They are for vm34s Mikunis which are a round slide carb not the stock bs36 Mikunis.
Along with the port that is going to be bigger,but relocated 3/16 in. horizontally and 3/16 in. vertical.

Wasn't saying you would have any problems, just stating what happened with mine.
1978 kz 400 single carb, now 440 top end hybrid
http://www.dotheton.com/forum/index.php?topic=28708.0

2008 Suzuki SV650

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #12 on: Aug 22, 2012, 16:24:01 »
Yes I'm sure about those carbs.
Stock the power peaks at 8500, Mr. Hyde will peak at 10000.

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #13 on: Aug 22, 2012, 17:02:35 »
Wasn't saying you would have any problems, just stating what happened with mine.

Sorry about sounding a little harsh.
Did you use the little trick I learned the hard way years ago?
That is leave a nut on the bolt to help clean up the cut so you can get a nut on said bolt.
But by all rights when inserting a bolt/stud into aluminum we should be using anti seize.
And how many of us have used anti seize on carb boots?  I know I have'nt.

On a side note about head milling and pistons for the 400,use the Wiseco KZ650 piston with the above mentioned milling will net you :65x62,411cc,10.45/1( early head ) and 9.65/1( late head )
With the 440 use the Wiseco KZ750/4 piston with the above milling will net you :69x62,463cc,9.3/1.
The valve pockets are not at the same angle but will work with the stock cam.
« Last Edit: Aug 27, 2012, 20:55:42 by Nebr_Rex »

Offline Shermanator86

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #14 on: Aug 23, 2012, 08:45:12 »
Sorry about sounding a little harsh.
Did you use the little trick I learned the hard way years ago?
That is leave a nut on the bolt to help clean up the cut so you can get a nut on said bolt.
But by all rights when inserting a bolt/stud into aluminum we should be using anti seize.
And how many of us have used anti seize on carb boots?  I know I have'nt.

On a side note about head milling and pistons for the 400,use the Wiseco KZ650 piston with the above mentioned milling will net you :65x62,411cc,10/1
With the 440 use the Wiseco KZ750/4 piston with the above milling will net you :69x62,463cc,9.3/1.
The valve pockets are not at the same angle but will work with the stock cam.

No worries, I wish I had thought about using a nut on the end of the bolt. I just ended up hitting the end with a file to clean it up.

How much porting are you planning on doing to the intake side of the head? I've heard that there is a lot to be gained with these engines getting them to breath a little better.
1978 kz 400 single carb, now 440 top end hybrid
http://www.dotheton.com/forum/index.php?topic=28708.0

2008 Suzuki SV650

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #15 on: Aug 23, 2012, 16:44:27 »
The 440(and late 400) head is actually really good for stock or slightly modified engines.
The ports have just about the same crossection area as the early KZ1000, (73 - 80).
And the valves are the same size as the late KZ1000(81 - 2002), which are bigger than the early .
What I am building is not going to be fun to ride stop light to stop light, pretty much to the limit.
There are some things that can be done and I'll show them later.
A person will have to be carefull because some places that could use a little 'improving' are thin walled in the casting.

Offline teazer

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #16 on: Aug 23, 2012, 17:46:28 »
Yes I'm sure about those carbs.
Stock the power peaks at 8500, Mr. Hyde will peak at 10000.

62mm stroke, 10,000 Revs mean piston speed just over 4,000, so that's possible if rings are thin enough, but pushing things as you said.  Gas velocity through the carbs is 252 to 280 depending on how large you go on the bore.  300 is a nice number for that which equate to 32mm carbs.

It's doable but may be a little short of low to mid range.  It'll be interesting for sure.


Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #17 on: Sep 16, 2012, 23:17:25 »
I haven't had much time to work on the crank lately.
But it's a little lighter now,down from 15lbs. 5.2oz. to 11lbs. 8oz.
Still have a little polishing to do on the crank and the rods are next.
After that off to be shot peened etc..
Also the forged pistons are matched and only 2 grams heavier the stock.

.

Offline Nebr_Rex

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #18 on: Oct 08, 2012, 03:00:05 »
Here is pic what's been done to crank.
And a pic of the carbs I'm taking off.
And what I'm putting back on.

Offline BLSully

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Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #19 on: Oct 19, 2012, 21:13:41 »
Nebr_Rex,

You just posted on my thread making sure I knew about the 2stroke vs 4stroke restrictor on the VM30s for my KZ400.

Your thread, while short, is exactly what I needed to read! I don't have near the skill or resources you do, but this is the direction I want to go with my motor...slight compression bump....I'm not too worried about a 10k redline, but I am curious about a couple things.

1) I know the KZ400 has a balancer due to the 180 firing... how does the lightened crank affect that? or... does it not affect the balancer as long as the crank itself is balanced (like any normal engine w/o balancers?)

2) I take it the Weisco's were a straight drop in since you said the pins are the same, and they have the same 64mm bore as the stock 400 motor?

Appreciate your documentation here... I'm sure I'll have more questions as the bikes progress through the winter.
'05 Vulcan 1500 Classic - Daily rider.
'79 KZ400 B2 - http://www.dotheton.com/forum/index.php?topic=42063.0
'80 KZ440 - Actually runs.

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