Jetting the ZX7R - Sportbike Forum: Sportbike Motorcycle Forums
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post #1 of 11 (permalink) Old 01-05-2003, 03:38 PM Thread Starter
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Jetting the ZX7R

I have a 2002 ZX7R and I'm thinking about jetting the carbs. Any suggestions for manufacturers? Places to purchase online? Anything I should know before starting?
No other mods at this point and I dont plan on changing the exhaust at this point so a stage one kit should be fine for me.

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post #2 of 11 (permalink) Old 01-05-2003, 03:46 PM
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You really don't need to jet the 7R. You just need to shim the needles. Go to Home Depot, and buy yourself some #4 washers. Pop the tops on the carbs (4 screws) pull out the needle, throw a washer on it, and stick it back in. You'll probably need just one washer per needle for stock exhaust. I'm running a full system, and I've got the equivalient of 2+ washers on there (just a Teeeeeny bit more then 2 washers), and it runs sweet now.
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post #3 of 11 (permalink) Old 01-06-2003, 03:50 PM
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AZRider,

As Kelvar says, raising the needles will probably correct most of your problems, however, I recommend getting to a Dyno and making sure of the main jet selection. If this is not where it should be, no amount of playing with the needles will help. What works on one bike cannot automatically be applied to another. A number of things can, and often do, result in different jetting selections among otherwise identical machines.

If you really want to get super performance from your carbs, look no further than the Flo-Commander. [ flo-commander.com ]
I still install jet kits on a regular basis, but the Flo-Commander renders a much greater performance increase. After installing a jet kit, my customers will say something like "I think it's a little better and the flat spot is pretty much gone too". With the Flo-Commander, it's more like "O my God, I can hardly keep the front wheel on the ground".
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post #4 of 11 (permalink) Old 01-06-2003, 05:09 PM Thread Starter
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Thanks for the info guys. I think I'm gonna try the 4mil washer thing first. See how that works. I have this lean surge thing going on below 5 grand and I'm hoping this will fix it up.

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post #5 of 11 (permalink) Old 01-07-2003, 07:31 AM
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Not 4mil washers..... #4 washers... Number 4 washers.
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post #6 of 11 (permalink) Old 01-07-2003, 08:42 AM
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i can't speak for the zx7, but some bikes use phillips head screws to secure the tops. it's not a bad idea to try to find an allen head screw of the same size if you have the phillips head screws. it'll ease your life greatly (less chance of stripping the heads). home depot or lowe's should have what you need.

btw, i personally like factory-brand jet kits. avoid the ti race kits though.

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post #7 of 11 (permalink) Old 01-07-2003, 11:04 AM
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Thats a damn good idea, Tony.

Yes, the ZX-7R has 4 phillips head screws securing the tops of the carbs. One of the 16 screws is different, though, because in addition to securing the carb cap, it holds the Choke cable stop. It has a little brass bushing in there to make up for the size difference. Let me tell you, that thing is a pain in the ass. After dropping mine (outside the carbs) numerous times, I gave up on looking for it. And of course its brass, so you can't go find it with a magnet. Oh well, it all holds together just fine without that stupid bushing.
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post #8 of 11 (permalink) Old 01-07-2003, 02:03 PM
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FZR400Tony,
Switching from Phillips head screws to Allen head screws is a debatable idea. I much prefer the Allen head items as well, but there is one considerable risk. The Allen hd screws provide far greater tightening capability. In other words they can easily be over tightened.
Over tightened screws is absolutely the number one problem I encounter in my shop. One of my customers recently bought a used set of FCR 39s, for example, for his ZX-9 and nearly every one of the top cover and float bowl threads were stripped out in the carb bodies. So many guys just don't have the slightest 'feel' for how tight to tighten things. They seem to believe that the tighter the better. If you watch them, they tighten even the little 4 and 5 mm screws as if they were head bolts. Of course the risk becomes the greatest on the frequently removed screws. For the most part, damaged threads are very difficult if not impossible to repair on a carburetor. So easy does it. Just remember that in most instances, an insufficiently tightened screw is far better than an over tightened one.
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post #9 of 11 (permalink) Old 01-08-2003, 05:11 AM
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Quote:
Originally posted by DaveL
FZR400Tony,
Switching from Phillips head screws to Allen head screws is a debatable idea. I much prefer the Allen head items as well, but there is one considerable risk. The Allen hd screws provide far greater tightening capability. In other words they can easily be over tightened.
Over tightened screws is absolutely the number one problem I encounter in my shop. One of my customers recently bought a used set of FCR 39s, for example, for his ZX-9 and nearly every one of the top cover and float bowl threads were stripped out in the carb bodies. So many guys just don't have the slightest 'feel' for how tight to tighten things. They seem to believe that the tighter the better. If you watch them, they tighten even the little 4 and 5 mm screws as if they were head bolts. Of course the risk becomes the greatest on the frequently removed screws. For the most part, damaged threads are very difficult if not impossible to repair on a carburetor. So easy does it. Just remember that in most instances, an insufficiently tightened screw is far better than an over tightened one.
good point about over tightening. over-tightening is something i've learned the expensive way to quit doing. a lot of people over tighten a lot of things, especially wheels.

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post #10 of 11 (permalink) Old 02-27-2016, 07:17 PM
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2001 zx7r with moto gp shorty pipe

Which Jet kit should i get for mt ZX7 since i installed the shorty pipe?
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