smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 08, 2010 08:17 PM
1498 cc STX-ninja Hybrid motor
I put this in the zx12r section but I haven't gotten a response, I am building a 2005 stx15f jetski but i am running a bunch of ninja parts in the motor, the ski engine is just a stroked out zx12r motor without a transmission.
so for all of you big bore guys what do i need to look out for since this is just a lazy stroked out zx12r motor
the bore is the stock 83mm with a 69.2mm stroke.
the current stock zx parts I am using are
2000 zx12r throttle bodies
2000 zx12r cams
I also have ferrea stainless stock valves and #65 carpenter valve springs and a ported cylinder head I'm running a uni filter on each throttle body
2000 a1 model ecu and wiring harness
with the BDM mod so i can tune it.
the compression ratio in the motor right now is 10.6 to 1 but i am planning on either running the je 9.8 to 1 turbo pistons that would put me at around 12 to 1 with the longer stroke. naturally i will check for valve clearance. but I want to keep it pump gas safe 91 octane because if i need to fill up on the water i want a margin of safety.
the only other mods I am running are 38 pound fuel injectors from an ultra 250x jetski at 50 psi to get them up to 41 pounds that will let me keep the injector pulse width the same. Im not planning on running a PCIII or anything like that.
I am planning on dropping the rev limiter to 8700 for the forged je.
If yall have any advice for me that would be great,
Thanks
Sean
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1498 cc
69.2mm stroke
83mm bore
  
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entropy
Moderator
Posts: 8671
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posted April 09, 2010 12:10 AM
Sean,
Really glad you came to Dragbike Zone! We like projects like yrs.
Although there is some drag bike stuff here, we REALLY like the technical build/tune issues.
The top tech experts visit/post here often, people like Doug Meyer, Y2K (Jim of Competition CNC), TimChin, and many others.
I'm lovin' the project you are doing, and the attention you are giving to details. from yr post it seems like you have strong technical skills, yup.
Do you build yr own motors?
Is yr jetski for competition? ( i know nothing about jetski world, never even been on one 
Yr profile shows Houston so I am a "neighbor", down in Sugar Land.
Karl
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This moderator uses moderation in moderation
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 09, 2010 04:58 AM
I am fairly technically inclined, and I am learning more and more as I go, this is not my first motor build but it is my first Jetski motor. I am building it myself.
I picked up the jetski from a friend of mine for 500 dollars last summer because they had let it sit on a floating dock for a few years and the salt water had gotten to it and trashed it. The ski is being rebuilt from the ground up and the engine has been stripped and cleaned and pending pistons and rings is ready for reassembly.
it is not a race ski just a project that I am doing to beat up on the newer high dollar supercharged skis...
thanks for the interest
Sean
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1498 cc
69.2mm stroke
83mm bore
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entropy
Moderator
Posts: 8671
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posted April 09, 2010 07:15 AM
I assume you have a workshop manual from kawasaki?
are the cams an exact fit especially with respect sprockets & timing? Or do you need to degree them?
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This moderator uses moderation in moderation
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 09, 2010 08:13 AM
yes i do have the manuals for both the ski and the bike, the cams are drop in and go no degreeing nessecary.
Sean
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1498 cc
69.2mm stroke
83mm bore
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entropy
Moderator
Posts: 8671
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posted April 09, 2010 09:48 AM
no degreeing will make yr life a lil easier; and having both manuals is perfect.
do you have a MC or are you a pure jetski guy?
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This moderator uses moderation in moderation
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 09, 2010 10:05 AM
Just the ski, I have a 4wheeler also, all kawasaki for me, I have a 2004 stx12f (stock ski) 2005 stx15f (project ski) 1987 Bayou 300 4 wheeler (project from hell)
Sean
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1498 cc
69.2mm stroke
83mm bore
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gilberjj
Needs a job
Friend of Fast
Posts: 3196
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posted April 09, 2010 12:19 PM
sounds cool! good luck
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 09, 2010 01:08 PM
Thanks, i am hoping to have the motor and electrics done by the middle of may, I am attending the mudbug rally the first weekend in june. so it needs to be finished by then
Sean
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1498 cc
69.2mm stroke
83mm bore
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KZScott
Needs a life
high on speed
Posts: 7235
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posted April 09, 2010 03:12 PM
I would double check cam timing and definately PTV just to be sure that adjustable sprockets are not required
why are you considering dropping the rev limit?
stock CR for a 12 is 12.2:1, works fine on pump gas, and since you are using the zx12r ecu i assume timing maps would be the same unless the crank trigger is different?
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 09, 2010 05:45 PM
The jet pump in for the jetski loses efficiency above 9000 rpms
Sean
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1498 cc
69.2mm stroke
83mm bore
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 12, 2010 11:53 AM
I will be using the stock crank trigger for the ski, its the same style as the zx one, the 8 point rotor
Sean
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1498 cc
69.2mm stroke
83mm bore
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 21, 2010 09:57 PM
I have an update, I will be using a fully programmable ecu made specifically to fit the stx15f harness, so I will be taking the program off of the zx12r ecu and loading a modified one onto the empty ecu. is there anything i need to look out for with the long stroke? I checked the piston speed of the stock 12r and took that and knocked 15 percent off of that for safe measure because the motor will be run for long periods of time at full throttle and calculated the correct RPM for the longer stroke.
any advice yall have would be great
Sean
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1498 cc
69.2mm stroke
83mm bore
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entropy
Moderator
Posts: 8671
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posted April 22, 2010 05:29 AM
smokey
"I have an update, I will be using a fully programmable ecu made specifically to fit the stx15f harness, so I will be taking the program off of the zx12r ecu and loading a modified one onto the empty ecu"
how in the world are you doing this?????
Karl
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This moderator uses moderation in moderation
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted April 22, 2010 06:34 AM
I have a full set of maps for the zx12r that i got from the zx ecu hacking website, so i will be taking the the program and either building one from that map, or using the actual map from the ecu if it fits
Sean
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1498 cc
69.2mm stroke
83mm bore
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted March 03, 2012 07:04 PM
 Edited By: smokeysevin on 4 Mar 2012 03:39
I know this is a really old post but I have gotten the motor started and I need some help sorting out issues. The motor is running but cylinder number one is not firing, the plug is wet and the coil is good and sparking, The throttle body on cylinder number one is the closest to the hull but there is an inch or so at the bottom and 2 inches at the top between the hull and the throttle body. Cylinder number 2 is the next closest to the hull and it fires and the plug is brown with a little fuel on it, cylinders 3 and 4 have the most room and both are a dark brown color. How much space is there between the end of the throttle body and the top of the intake box on the bike? Next, the motor will not start unless the battery is just off the charger, I have tried 2 separate batteries but after trying to start a few times it will slow and its dead, the voltage drops to under 12.5 volts from 13.4 very quickly, On the built bikes what sort of voltage do yall run on your starters?
http://www.youtube.com/watch?feature=player_embedded&v=m15I__CAK0c
Thanks for taking the time to read, I really appreciate it
Sean
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1498 cc
69.2mm stroke
83mm bore
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dougmeyer
Needs a job
moderated
Posts: 2713
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posted March 03, 2012 07:42 PM
Anything under 12.4 won't power the ignition. Sounds like you might have a problem in the wire harness, reg /rectifer. There is a big current draw somewhere. I also think there is low voltage going to #1, resulting in not enough power to fire the plug when in cylinder pressure. A challenging electrical dilemma- especially when you have a suspect (not new) harness. No fun.
I think the injector body clearance is a distraction. It wouldn't make any difference, especially at low airflow.
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It's not that I think you're dumb, it's just that so much of what you know isn't true....
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted March 03, 2012 07:57 PM
Ok, I will run through the harness and check the rectifier. The jetski motor uses a waste spark setup so it's not just firing one plug, it fires 1 and 4 at the same time. I left the ignition on last night with a 1.5 amp trickle charger and when I went to bed it was at 12.5v or so and by this morning it was at 11.8v so something is really killing it. I just can't figure out why 3 and 4 would fire and 1 wouldn't and 2 would be wet.
Sean
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1498 cc
69.2mm stroke
83mm bore
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KZScott
Needs a life
high on speed
Posts: 7235
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posted March 04, 2012 04:54 AM
Edited By: KZScott on 4 Mar 2012 12:55
what are you running for coils? my turbo bike with MS2 ecu is also firing in wasted spark but still retains the oem coils. i did up the dwell time. if you are using a zx12r map is it possible your dwell time is what kawi used for a NA 12? Might be a little low? just guessing...
I did notice that #1 seemed to foul the easiest at idle in the early stages of tuning. no idea why? might have been the batteries. I put 2 new ones in shortly after getting it going last yr. you would think that in wasted spark the paired cylinders would behave the same?
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted March 04, 2012 06:51 AM
Edited By: smokeysevin on 4 Mar 2012 14:58
I didn't even think about that, yes they are stock jetski coils with a single primary winding and 2 plug wires. I will up the dwell time a little. The max charging current is 8 amps for 3500 micro seconds. right now.
Sean
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1498 cc
69.2mm stroke
83mm bore
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dougmeyer
Needs a job
moderated
Posts: 2713
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posted March 04, 2012 08:26 PM
You really have a current and wiring problem. Things start to go south at less than 12.8V.
Also wasted spark systems really don't matter much because--- The wasted spark does not require (use) as much of the available energy current as the firing spark because without the compression pressure less current is required to jump the gap. It's not like trying to fire a double plug in one cylinder.
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It's not that I think you're dumb, it's just that so much of what you know isn't true....
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted March 04, 2012 08:41 PM
Yeah, I increased the dewll and charging current to no avail, with a 13.3 v charge on the battery with key off the charge drops to 12.8 with key on and 12.5 or less while cranking. When the motor does run though the voltage is steady at 13.3-13.5. I don't even know where to start looking for a draw that big though. Ill check the rectifier tomorrow.
Sean
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1498 cc
69.2mm stroke
83mm bore
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
|
posted March 05, 2012 05:55 PM
I pulled the starter motor today and cleaned every single piece that had a ground connection to the cable or the motor and reassembled the engine. In the process I noticed that I had flipped the throttle bodies over so the injectors were shooting at the wall of the port and not down it so I corrected that. I will test tomorrow, the cleaning of the grounds seemed to help but I am still getting a huge voltage drop. I will be picking up an amp clamp this week to check my current draw.
Sean
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1498 cc
69.2mm stroke
83mm bore
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2000redrocket
Pro
Posts: 1662
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posted March 05, 2012 06:50 PM
sean the guys with strokers have went to a 24v starting system. that spins them over. and if you get the throttle bodies off again hold them up to the light and do a rough air gap check and see if you are close or way off on the sinc between the cylinders. a injected bike like ours cares not how much air is getting in to the cylinder. it is spraying what it is told to.
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smokeysevin
Novice Class
ZX12r-STX15f hybrid motor
Posts: 82
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posted March 05, 2012 07:08 PM
That is what I have been thinking, there is a 14:1 cr kit for my motor and I asked the manufacturer today about the starting system, I am waiting to hear back about it. The throttles are synced and I will try to see how the flip effected the engine. As of now, the motor will spin fast enough to fire but then it fires weird and the motor stalls then spins over. The whole time its not running. Initially it was a cam issue because the cam position nub was set wrong but I fixed that and now I am hoping the fuel issue fixes my starting issue. If not its on to something else.
Sean
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1498 cc
69.2mm stroke
83mm bore
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