To dynojet or not to dynojet?

Hey guys.

I have been contemplating whether or not to buy a dynojet kit for my bike since I bought a Vance and Hines 4 into 1 and a K&N air filter.

The paperwork that came with the exhaust system says to buy the stage 3 dynojet kit since I have a K&N filter.

I have read so many different opinions on the dynojets; some say they are junk and won't last long, others say without it the engine will runner hotter than it is supposed to.

So I am asking you guys who might have a similar setup and experience in this department. I have a powercommander that I installed on my VFR few years back and have no complaints, but with carbs this is a whole different ballgame.

I don't want to spend the $$$ on a dynojet kit if I don't really need it, or if I can just buy new mains and pilots. I read somewhere that Z1 enterprises suggested 3 to 4 sizes up on the main jets and up 1 size for the pilot on a setup like mine (same bike too).

So whaddya guys think?

Thanks.

And forget to mention that I am still in the rebuild stage for my bike. The carbs were leaking from somewhere when I bought it last summer before I tore it all apart for the rebuild. The gas tank was rusted too, so I have bought 4 carb rebuild kits and was planning to work on the carbs next week during some vacation time. I don't believe the carbs have had any attention in the 30 years of their existence.

I would save your money and buy the mains and pilot and shims for the needle especially if you are using the stock air box.

I say save your money and don't buy the kit. call the guys at z1 enterprises tell them your pipe setup and buy mains and pilots for the next 3 sizes up. I was told that it would probably be at least up 2 sizes, mine is running perfect with 1 size up, so jet sizes are not universal. it can be different from bike to bike. I would try 1 size up and see if it gets better. Word to the wise those washer shims for the needle did not fit around my needles I had to use a drill and a pair of pliers holding the washer flush on a piece of wood at the edge of the wood while drilling free hand. I spent a bunch of time shimming and after all was said and done I have no shims on the needles and it runs fine. Try small adjustments first, oh yeah and put those aluminum plugs back in that some people say are optional, they were not optional for me, removing them caused a huge headache for me and when i put them back in everything was good. Make sure you have all the butterfly valves even. I would make sure to adjust your fuel/air screws to the stock position to start. tighten them all down and back them off 1 1/2 turns to start. After you get the jets as close to perfect as possible you can do fine adjustments with the fuel/air screw (very minimal, if its any more than a minor hiccup you still dont have the right jets in). Make sure you have an airtight seal on all the carbs too. With my bike running pods I hade to fine tune with the fuel/air screws, I have k&n pods and a vance and hines on a csr 1000 and the 2 inside cylinders were running a little bit leaner than the outside cylinders. Get it as close to perfect as possible and put some miles on her and then take a look at you plugs. More air= leaner, whiter/lighter looking plugs, more fuel= richer brownish/black looking plugs. I'm not a pro by all means but this is the checklist I used and my bike is running as good as I could hope for. Good luck!

Oh yeah and I think that paper they put in the box is some back door deal between the carb company's and exhaust companies, think about it it benefits both of them, If you open the box for your exhaust and it says you need a stage 3 kit you think, Wow! this thing is gonna rip when I get done, and you go out and spend extra money to buy the "kit". not neccesary in my opinion. Call Z1E and ask them, they'll tell you not to waste the money either.

Awesome. Thanks for the input guys. I am psyched about working on the bike all next week, and this is great advice.

5 days off, no kids running around screaming, bunch of new parts, and some beer and tunes in the garage...it doesn't get any better than that.

Now I'm torn. I was just told by Mike at Z1 enterprises that my best option with the stock airbox is to buy the Dynojet kit for 100 bucks.

They have never steered me wrong before, and I trust their knowhow...but not sure if I'm going to spend the money on that kit or not.

I never put a DJ kit in a KZ, but for my honda shadow, I did. The DJ kit came with a few sizes of jets, and more importantly, the adjustable needle that had a different taper than the stock. I've heard people say you can shim the stock needles, but its not the same as the DJ ones.

Anyway, my pipes called for a certain setup for no baffles and a K&N. I tried this first of course. It ran ok, but seemed to be a bit rich. I played with adjusting the needle clip and different sized jets and settled on the recommended needle setpoint, but one jet size smaller and I was golden.


If you think about it, the DJ kit can seem like a rip off because the jets they give you Z1 can get for under a few bucks. I tried to call DJ and get just their needles, and they wouldn't sell just them .

"pre-determined" aftermarket jet kits are a complete wallet bait gimmick IMHO ! "jet kits" for a bike are fine tuned on a dyno with a randomly chosen bike, at a given room temperature, for max hp. This looks way cool on a piece of paper when you see a whopping 6 additional hp above 7000 rpm's . The experts know that every engine is a little different, and that an engine in arizona is going to run totally different than an engine in North Dakota. So this being said, what happens if you install said jet kit, and now your driving the bike in 55F temps ? The "predetermined max hp jet kit is now running lean, and you are loosing hp. Everyone has the misconception that after you add a performance pipe you need to throw much richer jetting, this is many times false. I've jetted a half dozen bikes some stock, and some with a pipe, and generally speaking all's thats needed is a slightly richer pilot and shimming the needles. However, if you've added pods, good luck you're on your own. Pods suck period, and I don't waste my time with them. I don't get fussy with jetting my bikes. I jet for ideal street running around 65. This is an "average" temp up here in New Hampshire. So when the temps are up near 80, i'm rich, and when the temps are 50 im running lean. I also jet to ensure good colder weather starting and off idle performance. This is where so many bikes run lousy from too lean EPA mandated jetting. Now in regards to my 2 stroke dirt bikes where correct jetting is critical to reliable engine life, I have a "summer" jet spec, and a "colder" jet spec to ensure that i'm not running too lean in the colder temps.

On my 750 I put some dunstall clamp ons on with fiberglass wrap. Just richened up the pilots a hair and away I went.

Seems like the intake affects the jetting much more than a pipe does, unless its straight pipes.

Just keep this in mind, the mikuni jets and the Dynojets jets are not the same size for the same number www.jockeyjournal.com/forum/showthread.php?t=64769 A mikuni jet is 93.75% of the same number Dynojet jet. More then 1 bike has been left lean as a popcorn fart because of this

Good point mtkawboy. I used this chart here:

Width

---

Keihin # -- DynoJets # -- Mikuni #

0,0540---- 140

---

130

---

121,9
0,0550---- 142,5

---

132

---

123,8
0,0560---- 145

---

134

---

125,6
0,0570---- 147,5

---

136

---

127,5
0,0580---- 150

---

138

---

129,4
0,0590---- 152,5

---

140

---

131,3
0,0600---- 155

---

142

---

133,1
0,0610---- 157,5

---

144

---

135,0
0,0620---- 160

---

146

---

136,9
0,0630---- 162,5

---

148

---

138,8
0,0640---- 165

---

150

---

140,6
0,0650---- 167,5

---

152

---

142,5
0,0660---- 170

---

154

---

144,4
0,0670---- 172,5

---

156

---

146,3
0,0680---- 175

---

158

---

148,1
0,0690---- 177,5

---

160

---

150,0
0,0700---- 180

---

162

---

151,9
0,0710---- 182,5

---

164

---

153,8
0,0720---- 185

---

166

---

155,6
0,0730---- 187,5

---

168

---

157,5
0,0740---- 190

---

170

---

159,4
0,0750---- 192,5

---

172

---

161,3
0,0760---- 195

---

174

---

163,1
0,0770---- 197,5

---

176

---

165,0
0,0780---- 200

---

178

---

166,9
0,0790---- 202,5

---

180

---

168,8
0,0800---- 205

---

182

---

170,6
0,0810---- 207,5

---

184

---

172,5
0,0820---- 210

---

186

---

174,4
0,0830---- 212,5

---

188

---

176,3
0,0840---- 215

---

190

---

178,1
0,0850---- 217,5

---

192

---

180,0
0,0860---- 220

---

194

---

181,9


Which I found on another forum.