posted January 31, 2002 02:43 PM
I'm shure some stacks crush more on some bikes.
Its a mass produced machine, I guess its acceptable.
____________
Y2KZX12R
CompetitionCNC.com
posted January 31, 2002 11:30 PM
I figured that the crush could even relate to how the motor was set/hung in the frame at the factory...motor up higher leaves less space for the ducts...
I've seen 2-sets (bikes) so far that were rippled bad enough to bother me...
posted February 02, 2002 06:32 AM
Edited By: Y2KZX12R on 2 Feb 2002 06:33
I just wanted to point out one thing that people need to realize on the topic of airflow and smoothness.
The velocity in these 46mm throttle bodies is VERY low.
Simulating the maximum flow velocity on the flow bench was amaizing. I'm used to doing race v8 heads with MUCH higher velocities where the smoke accelerates bigtime upon entry into the port.
The zx12r has a potential airflow volume that is almost 5 times the engines requirements.
I recently was working on a 502 BBC with a holley dominator that flowed less air than the zx12r throttle bodies at the same test pressure.(10") If you were to put that carb on a 300 hp chevy engine it would be way to big for the engine.
Can you see what I'm tryng to point out here?
Think of it this way... if you had an imaginary column of air above the throttle body it would be moving at 3.83 feet per second. The column of air over this dominator at peak power is moving almost 5 times the velocity. Pressure drops are needed to create a pressure differential between the air above the fuel in the float bowl and the the booster venturi. This is what makes fuel flow in a carb.
With fuelinjection a pressure differential isnt needed so you can effectively RAISE the airpressure available to the back side of the intake valve. Now you can start to see why fuelinjection is desireable.
posted February 02, 2002 09:18 PM
Y2K, please describe the reed valved airbox plates you mentioned. Just curious. I want shorter stacks! Be kinda difficult, I believe.
quote:I inspected mine and even removed them. I can't find or feel any discernible lip. At best, there might be a lip of LESS then 1 mm. There is a slight "dimple" about 4 mm from the edge, but running my finger over the point where the rubber ends and the throat of the TB starts, there really isn't any difference.
This makes me think that it's just a poor tolerance from the factory. Like Doug and others have said, it doesn't hurt to have a smooth transition between the two pieces, but I don't think that this "lip" was designed into the bike. In other words, I could see the size of these lips being different from bike to bike.
I have taken some crappy pics (I didn't take off the tank), it's just that I have no where to post them. They basically shows a smooth transition between the two pieces. Any cutting I did could easily cause more problems then solve. With a lip of less then 1 mm, if I did cut, it could expose the edge of the throttle body and just create more turblance.
The lip is about 1 1/4 mm thick and about 8mm wide both edges are square. Take off one of the boots and look. The lip is there. When it is ground off the transition betwween the boot and the TB is dead perfect. If you ever owned a ZX11 that had a very good fitting boot and the transition was almost perfect.They went through great pains to make it right. Also they don't usually put oversize TBs on their bikes, then neck them down, unless they are restricting them. They like to keep the TBs as small as possible to keep small throttle openings under control and velocities up. This type of restriction, IMHO is done to cause turbulance and friction, not just a simple neck down.
____________
Ted
2000 Green ZX12 sold
The fast color!!
Green 2005 ZX10R
2009 Concours Black ABS
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posted February 03, 2002 12:42 AM
Edited By: redelk on 3 Feb 2002 00:54
"The lip is about 1 1/4 mm thick and about 8mm wide both edges are square. Take off one of the boots and look. The lip is there."
Ted, as I said earlier...
"I inspected mine and even removed them. I can't find or feel any discernible lip. At best, there might be a lip of LESS then 1 mm."
As I said, I have removed all four of them and throughly inspected them, VERY closely, for ANYTHING that might even resemble a lip or raised surface. I still can not find any kind of lip and especially have not found anything close to what you have described.
I have NO DOUBT that you are telling the truth in the case of your boots, it's just that mine do not in any way, match the configuration you have explained. Why? I have not a clue. I do know that I have spent quite a bit of time in removing and reinstalling my boots, several times, in an attempt to create any kind of lip that can be felt, measured or observed... and I can't do it.
The fit between the TBs and the rubber boots are as straight and flush as humanly possible. There is no rise, lip, or any other form of change in the diameter in the boots to the TBs. The only exception to that is the "dimple" I mentioned earlier. Still, after the dimple, it returns to the same diameter as the TB. Also, this "dimple" has no square edges and is LARGER, not smaller, then the diameter of the TBs.
Tomorrow, I will measure them with a micrometer, first, while they are installed and the I will remove them again and measure them off the bike. I can honestly say that I'm confident that the openings of the boots will either be equal to or even larger (when they are out of the bike) then the oppenings of the TBs.
If there is any difference, I'll be surprised if it's anything measurable. What you have described, "... 1 1/4 mm thick and about 8mm wide both edges are square.", seems like something that would be fairly obvious. Especially when you say, "both edges are square.". One thing I know for ABSOLUTE CERTAINITY is that I have NOTHING in my boots that are anything like that.
AGAIN, I am in NO WAY doubting your word on this. Why mine is not configured with this lip is beyond me. I don't know if it's because mine was one of the first ones to arrive in this region and it "slipped" by the "booty boys" or what. Still, I do think that if I had anything with both edges being square, it would have to have been moulded that way and I'd be able to feel, measure or see it. The only edge that is square on my boots are the ones that are at the end of the boot that fits against the TB. There is no second square edge on the boot. None of the four boots show any "deformation" while in or out of the bike.
Also, if the lip is approximatly 1.25 mm, that would work out to about 0.049" or just a tad over 3/64". So far, if there is any difference in the diameters of my TBs and my boots, they appear to be in the range of less then 1 mm or somewhere around 1/32" (or less. Going on the volume and air flow speed information from Y2K, I'm hard pressed to see the .035" or so making that much difference. Again, Im just referring to MY boots.
I don't really know what else to say, besides it ain't there. At least on my boots.
____________
There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
posted February 03, 2002 09:36 AM
Red,
If there is not lip on yours, that could mean only one thing, that they changed them after the fact and missed yours!! More proof. It wpold be great if yours really did not have any lip.
____________
Ted
2000 Green ZX12 sold
The fast color!!
Green 2005 ZX10R
2009 Concours Black ABS
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Posts: 3212
posted February 03, 2002 10:11 AM
That could be a possibility... Since I've kinda been "forced" to do some "additional servicing" on my bike, I might just take the tank off and take some more pictures of the boots installed, as well as out of the bike.
I'm being "forced" because of the hassles I've been having on getting the threaded bung put into my header (for my O2 sensor). I have already checked my valves and did the oil pressure mod.
Yesterday, I thought I'd just change the oil in my forks. I was going to send them to Race Tech, but an unexpected change in my "finacials" ain't gonna let that happen. Like a TOTAL IDIOT, I had already removed the forks before loosing the top caps. Note to anyone working on their forks... if your breaking loose the caps on the forks for the first time, BREAK THEM LOOSE WHILE THEY ARE STILL IN THE TRIPLE CLAMPS!!!
With two other people holding my fork, there was no way I could get that 30mm cap off. I go to my dealer and the service manager just happens to have an aftermarket triple clamp for a KX250. All the while, I'm thinking that doing it in their shop will be great, since I'll get to use their high dollar fork gauge to refill them. With a little help, I get the caps loose (notice I didn't say "off").
To access the nut on the push rod, you have to compress the fork spring. That's when we make the very ugly realization that a "special tool" is required. We couldn't find anything else in their shop that would work. Kawasaki part number 57001-1452 is for the "fork spring compression set". I don't know if this took is just for the 12R on not, but none of their mechanics could figure out any other bike that need such a tool.
Even though there are less then a half dozen 12Rs (still running... most of them have been totaled) in Arkansas, this is the first time they (or I) have attempted to change the fork oil on a 12R. Well, sometime around this coming Wed., my dealer will have this tool. Dealer cost is around $230, so I sure as hell ain't buying one for myself.
So, since I won't see my header back until mis this week and I can't do anything with my forks until the "special tool" arrives, I got a lot of spare time on my hands. Watch the Super Bowl? Hell, don't ya'll know? If it ain't got a motor in it... it ain't a "REAL" sport!
____________
There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
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Posts: 3212
posted February 03, 2002 10:25 AM
I think my dealer... is starting to agree with you! There really isn't any other way to compress that spring, is there?
____________
There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
quote:is starting to agree with you! There really isn't any other way to compress that spring, is there?
Well during the Xmas holiday I ran in to the same problem. It took a little while before I get around it - but it is possible with the tools You probably have. You only need on of those things You tie thigs down for example Your motorscyle when You are trailering it(I don't know what it is in English). And then You also need two bolts and something to tighten the tie to the collar over the spring.
Here is a picture which I painted(don't laugh)
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posted February 06, 2002 07:36 AM
Thanks, tuusinii That's a great idea and I hope Fish saves it for the "library"! I had thought of trying it, but since the "special tool" will be arriving at my dealer today and it won't cost me anything to use it, I'm just going to wait on it.
That is if the snow goes away. We got 4" last night. It might not seem like much, but for a state that has a TOTAL of 7 salt/sand spreading trucks (4 of which actually have a snow plow blade on front), it pretty well "paralyzes" the state. The funny part is that the majority of roads are now just wet slush.
The not so funny part is that it will get up to 60° F this weekend. What could be "bad" about that? Even with the few spreader trucks we have, every twisty back highway will be covered with sand until we get at least two or three days of good rain to wash it off. Coming around a blind corner and seeing a wet spot or gravel is bad enough, but to have huge patches of sand is the worst I can imagine.
The only thing worse is imagining me in a short sleeve t-shirt, working on my bike and looking out my garage at what would have been a beautiful riding day!
Anyway... kinda back onto the "original topic"...
This is a reply to Vincent Hill (and others) from Horsepower Mike on the LAB thread. It's worth noting that there are also posts that have a different view on that same thread. I believe they are also well worth viewing. Though I tend to agree with HPM, kcadby and others of like mind on this, I hardly have the mechanical or engineneering knowledge or riding experience to contribute to the discussion.
My apologizes to Mike for "pirating" his post...
Vincent... Mike here from Horsepower Unlimited.
I have been following this post for a while, and figured that I would give people some info, and clear up some myths. The factory throttle bodies on the zx-12 flow very good. They flow 149 cfm per body. They flow better than the busa's throttle bodies, even though they are the same size due to a slightly better design. When we bore the throttle bodies to 48mm, they flow 170. I can guarantee you that the factory intake stacks outflow the throttle bodies even with the tiny lip that is created around the outer edge when they are bolted down.
When air flows through a round hole such as that, the air moves very slow at the outside edges, and there is very little flow there due to the drag between the air, and the walls. This is laminar flow. The throttle bodies are 46mm, and people have measured the intake stacks at 44.5 mm where the lip is. The intake stacks flow very well because they are a wide open hole.
The throttle bodies are slightly bigger, but what do they have directly in the middle? A massive throttle shaft, and blade that runs directly across the middle of the throat where the air speed, and flow is the highest. In fact, the hole is no longer a wide open hole. It is now 2 half moon openings. The air is forced to split into 2 seperate flow paths. This is why a flatside, or smoothbore carb will badly outflow a cv carb of the same size, because when the throttle is wide open there is no throttle shaft, and blade hurting the airflow.
Removing the slight lip on the stacks will not hurt anything, and you may actually see a slight gain, and I hope that you do. For the people that think they will see a big gain, or a gain that they can feel, I believe they are mistaken. For the people that think that this is the way that Kawasaki restricted the bike, I believe that is definately incorrect. The reason that you have the slight lip is from the rubber being slightly deformed when the stack is bolted in place. This is how they make sure that it seals.
I look forward to seeing the results of the dyno tests that will be posted, and I hope that they are good. The problem is that I believe that the difference will be so small that it will fall into the normal varience from 1 dyno run to another. Hope this helps. Mike. ____________
There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
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posted January 31, 2002 02:43 PM
Edited By: 
posted February 03, 2002 12:42 AM
posted February 03, 2002 10:11 AM
posted February 03, 2002 10:25 AM
posted February 06, 2002 07:36 AM
