Thread: Smokeysevin's STX 12F Project
01-23-2009, 06:49 PM #1
Smokeysevin's STX 12F Project
So, I couldn't help but noticing that there wasn't a single 12F project on this site, and I figured I would start one up to chronicle and maybe, just maybe help some of the other 12Fers out.
My ski is a 2004 STX 12F that I bought in early June of 2008, the ski had 102 hours on it and had some slight imperfections in the hull where you could tell it had been beached several times. The engine was in near show room condition and the entire inside of the ski was nearly new.
The first few weeks of owning the ski was wonderful, that is until I caught the ski mod bug. After doing some searching I found some mods and proceeded to begin cannibalizing my beautiful Jetski...
The first mod that I did is a fairly common one amongst the STX F community, the Free flow intake mod. Rather than going about this with the filter in the bucket I went to Autozone and purchased a 3 inch Spectre intake 90 degree elbow, and connected this to the stock throttle body with a 3 inch silicon connector. I Then attached the filter (a 4 inch Spectre performance cone filter) to the elbow, This worked well but I did notice that the filter got dripped on from under the seat, so using the mount from the old airbox I took a piece of diamond plate and bent it to roughly a 30 degree angle then bolted it onto the airbox mount. This prevented anymore water from getting on the filter. For the valve covers I got 2 brass T connectors and using the factory tubes connected them together and using a reducer connected this to the factory oil separator. This allows you to only use one breather instead of 3 and is only about 10 dollars.
While this was good for a while, I still wanted more so I modded the factory intake grate by removing the center bar and sealing the ride plate holes with RTV. I DO recommend doing the intake grate, its free and it works, I noticed a big improvement of acceleration but didnít have access to a GPS at the time so I cannot verify any improvement. The Rideplate holes I DO NOT recommend if you ever want to change anything underneath it. IT IS THE BIGGEST PAIN IN THE BUTT to remove the silicone from the holes while lying underneath a trailer, just don't do it if you ever plan on removing it.
The third mod I preformed was what I call the OSBORNE EXHAUST. More or less itís just a 2.5 inch u bend of thin walled aluminum intercooler piping that I purchased from suprasport.com I think it was about 30 dollars shipped. When I got the pipe I cut roughly 1 inch off of the side that would eventually be towards the rear of the ski, this will help fit the pipe in with the factory exhaust connector. After cutting the pipe you then remove the secondary waterbox and the 2 hoses connecting it to the exhaust outlet and the primary waterbox I took the longer hose, I believe it was the one near the rear of the ski and cut it in half. Then, using the factory hose clamps and the cut hose, fit the new exhaust pipe onto the tubes and then to the waterbox and exhaust tip. MAKE SURE THAT THE HOSE CLAMPS ARE TIGHT!!! The last thing I did was to remove the little rubber piece from the factory exhaust tip, if you remove the 3 Allen screws from the exhaust tip you can pull the outside piece off and you will see a rubber "flapper" remove this and put the tip back on.
After these three mods I was able to borrow a GPS from a friend and with 2 riders 3/4 tank of gas and 47 degree weather we were able to hit 54.7 MPH, not terrible but definitely leaving more to be desired in my eye.
That being finished I moved on to the some what controversial TIMING ADVANCE MOD, this mod involves draining the oil, removing the engine cover from the front almost under the handlebars, removing the pulsing rotor and grinding a small bit out of where the timing key sits allowing you to clock the timing rotor more to the advance side. I won't go into more detail on this as it is discussed here. what I will say is that If you perform this please run premium fuel in the ski f you don't already as if you advance the timing too much you could get pre-ignition causing destruction.
So, that's what is going on so far, In the up coming months I will be purchasing a 15F intake manifold, throttle body, and injectors, along with an impeller and ride plate. I have every intention of building the fastest naturally aspirated true 12F and plan on bringing it to mudbug this year. So in closing for this section, if there is anything you all can think of that I may have missed or should elaborate on please let me know.
01-23-2009, 11:26 PM #2
If your going to fill the ride plates holes you need to do it a better way. I thought the same thing about the silicone everyone else was doing.
So I to use some rubber plugs I got from Ace harware. They are about $ 1.00 a piece so its a little pricey. Anyway I shoved them in but used some super glue while installing. Then the left over that sticks out I used a new Sharp razor blade and cut them flush.
Works slick and to get out just loosen the edges of the glue and pry out with a small flat screw driver or pick. If carefull they can be reused.
Although now I am using cork plugs and is cheaper and just as easy to place. Have not removed those yet but ethier way it is easier than and silicone method.
Im sure others will start doing this as well...
Anyway hope this helps.
01-23-2009, 11:30 PM #3
Yeah that's great, I was thinking about threading the holes with a really big tap and then using like a threaded insert but that sounds just as good and cheaper.
01-28-2009, 02:51 PM #4
Alright Guys I have an update of sorts, I have been looking for a set of zx12r throttle bodies and possibly a head, the throttle bodies will bolt up to the head with an adapter plate this is not a new idea, I think R Rated had the idea before me and even posted some pictures in another one of my "idea" threads. Everything should just plug in/bolt up but, before I embark on this does anyone know what the stock injectors on a zx12r ninja are? SO if any of you out there in internet land happen to have a set of throttle bodies or a way of making an intake manifold flange please feel free to let me know. I should have this going by February.
01-29-2009, 10:58 PM #5
After seeing this thread by BluBerri#52 it's got me thinking about the appearance of my ski and what I can do to set it apart from the rest of the crowd, While performance is my main goal I would love the outside of my ski to look as nice as it runs. So anyone with interesting ideas about what I should do to the appearance of my ski please let me know, I cant do mirror blockoffs because I tow tubes/wakeboards with my ski all the time but any other options on custom paint or decals or anything else would be great. I am also considering changing the kawasaki guage to several autometer guages kinda the same route the gprxp guys have been going, and I was wondering if that is even possible with the Kawi ECU.
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