collapse

www.dimecitycycles.com

https://www.townmoto.com/collections/vanson-leathers


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.lostapostlejewelry.com

www.cognitomoto.com

www.sparckmoto.com

www.pistonsociety.com

www.steeltowngarage.com


Author Topic: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)  (Read 50499 times)

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #80 on: Aug 18, 2013, 20:44:22 »
I love how it hits 9k and just takes off

I was slowly throttling up until around 7k and then just pinned it.
And Lord knows how accurate that old tach is, because it sounded like it achieved a higher
 r.p.m. than what the tach was showing.

.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #81 on: Aug 21, 2013, 20:25:59 »
Might have cured the off idle stumble, especially the dead spot between 3k & 4k.
I made some plastic bushings to reduce venturi size from 34mm to 29mm.
These are temporary and I'll have to make some smaller throttle bodies or
new bushings out of aluminum. They did add 1 in. of vacuum though.
But before that I dug out the modified fmu ( fuel management unit ) from
before. With it I gain about 10 p.s.I. when the throttle is pinned. I still use the
other pressure regulator to hold a base line fuel pressure. Without it the
pressure will drop to about 0 when the throttle is chopped causing the bike
to sometimes to stall. I also replaced the counter weight I cut up and the
heavier spring with stock pieces, thus speeding up the advance on ignition
and fuel curve. These all made some difference but what made the most was
adding 2 10k resistors to the top igntion module. Now the throttle can be
manipulated easily between 3k & 4k. I will need to take it for a spin tomorrow
to be sure.


.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #82 on: Aug 25, 2013, 22:21:21 »
Took it for a test ride and realized more fuel was needed because
it wouldn't pull past 5k in 1st and 4k in second. Went back and turned
up the fuel pressure by 5 lbs., it ran better with more r.p.m.. Put it
back on the lift and stared raising fuel pressure. Ending up being rich
at idle. Leading to the next step. Using a wide band o2 sensor hooked
to a pulse width modulator to control the fuel pump.


.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #83 on: Aug 29, 2013, 12:17:27 »
The wide band o2 sensor and pulse width modulator didn't live up to expectations.
The voltage signal out from the o2 sensor was not enough to run the pump past 20
p.s.i.. I am going to pull the fuel injection stuff off until I can save enough pennies to buy a
used oscilloscope, probably a Fluke series 90. That way I can see exactly when the
injectors are firing and for how long corresponding to cam and ignition timing. I will also
be going thru the top end with Wiseco KZ750 pistons and some work on the cam.
That will take displacement out to 463cc.

.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #84 on: Aug 31, 2013, 23:46:21 »
Got the head back,had it milled another .030 of an in..
Pics are of the stock chamber, next milled at .030 and
then at another .030. Found a belt to fit my tool post grinder
so I can grind down some base circles on the can.
The cycle shop was busy so the block isn't bored yet.


.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #85 on: Sep 03, 2013, 12:01:34 »
Got the block and pistons back from the cycle shop.
I have made some changes to the ignition pickup.
Moved the plate out so I could put the pickup for the
injection behind it. This was changed to fire the injectors
when the  intake valve is opening at around top dead
center vs. being at bottom dead center. Firing at the
bottom of the stroke most of the fuel was injected when
the intake is closed. By moving the point when the injectors
are fired. Half the fuel is injected when the intake is open
and half when closed. Because it fired once every revolution.
Also started on grinding down the intake base circle on the
cam for this engine. That was until I about burned up the bearings.
I filled up the oil cup several times but the shaft must have
been totally dry. Disassembled the shaft and still need to clean
it up so I can finish roughing in the base circle. Then I can
dress it with a die grinder. After that it will be check by degreeing
it in the engine after the the big bore pistons and milled head
are installed. When I'm satisfied with the results I'll polish it up
with some emery cloth. The factory retarded the intake timing
several degrees compaired to other engines. If I was
going to change that, might as well advance it a few more.
Add a few more degrees of duration and .040" of cam lift. Below
are some pics comparing a stock 750 plate and modified KZ400
points ignition advancer that I was using to the new setup. That
is a 440 ignition advancer and 750 plate modified as stated above.


.


Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #86 on: Sep 03, 2013, 12:03:00 »
More pics.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #87 on: Sep 03, 2013, 12:05:50 »
Pics of the ' cam  grinder '.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #88 on: Sep 04, 2013, 19:17:31 »
The bearings for my tool post grinder won't be here till Monday.
So I did a little porting.



.

Offline Nebr_Rex

  • DTT SUPPORTER
  • *
  • Posts: 853
Re: Dr. Jekyll and Mr. Hyde ( a pair of KZ400s)
« Reply #89 on: Sep 06, 2013, 19:53:08 »
Bearings came in today. Bought an extra pair just in case. Problem was this is the first time I used the machine. I put oil in the cup a few times, but that wasn't enough. Bearings, felt liner, the whole housing was dry. When it acted up the first time, I tore it down, cleaned it up and made sure it was full of oil.
Thinking the roughness  would come out of it, which it did during assembly and the first bit of use. Now
with new bearings and some spares I'm ready to start up again.

.