Keihin versus Dynojet numbers

[bearair]

How do Keihin jets equate to Dynojet numbers? I've got a Dynojet kit and they say to use a 165 or 170 for my application but I don't know how that corresponds to the Keihin jets. How do the two types of jets relate? Haven't found a chart yet with equivelant numbers.

[j450rking]

here you go!

jet sizing chart


Width------Keihin # -- DynoJets # -- Mikuni #
0.0350---- 92.5--------- 92----------- 86.3
0.0360---- 95----------- 94----------- 88.1
0.0370---- 97.5--------- 96----------- 90.0
0.0380---- 100---------- 98----------- 91.9
0.0390---- 102.5------- 100---------- 93.8
0.0400---- 105--------- 102---------- 95.6
0.0410---- 107.5------- 104---------- 97.5
0.0420---- 110--------- 106---------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
0.0510---- 132.5------- 124--------- 116.3
0.0520---- 135--------- 126--------- 118.1
0.0530---- 137.5------- 128--------- 120.0
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
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5

[CarGuy7a]

i don't believe that chart is correct.

the numbers are close to same. i've done alot of testing with this and found that if i ran a 165 dynojet main with the DJ needle and then swapped to a keihin 165 with the keihin needle they ran too close to tell a difference.

pretty much the only thing i've found that is different between the two is the dynojets have a different taper on the inside of the orifice. this is why they tell you to install the new needle provided in the dynojets jet kit.

[j450rking]

yeah i think your right they are way to close

[hornetgod13]

That chart keeps popping up and I have always doubted it's accuracy. Where did it come from and who made it? I think it was something someone typed up on the website years ago and it just won't die.

I had a Dynojet kit and ran it for a while but, eventually sold it and went back to Keihin jets. I've had better luck fine tuning and sharing jetting specs with Keihin.

[bearair]

So after looking at that chart, the Dynojet recommended jetting for my setup looks WAY too rich. I went with the recommended 165 dynojet from their sheet when I installed the kit the other day.

I have a slip-on, airbox lid modified w/six 1 1/2" holes, Curtis Sparks air filter and boot ring kit, Curtis Sparks 6 degree timing key and I'm going to grind the weld in the headers this weekend. I'm trying to get it ballpark before I go riding again without worrying about fouling a plug.

I'm at 2500' elevation and will ride between 2000 and 3000 most of the time. Temp right now is around 45-60 but it gets in the 80's by June and I'm sure I'd have to lean it out a step in the summer.

Any recommendations on which dynojet jet to use initially? I can read a plug but it would be nice to be in the ballpark on the first ride without having to tinker. It's about a 30 minute drive to where I ride and I don't want to be working on the bike at the riding area.

[bearair]

Tried the 165 main in it, it was way rich. Got a good puff of black out of the pipe when gassing it under load. Dropped down to the stage one recommended jet for a pipe and airbox mod (146) and that's WAY close. Took it out tonight and gave it a good ride and found all the mods have woken it up considerably.

It pulls hard compared to stock. Have to get way forward to keep the front anywhere close to the ground through the first three gears. The power difference is really night and day. It's a lot more fun!

To recap, I've got the Curtis Sparks timing key and filter kit, dynojet kit, airbox lid drilled with six 1 1/2" holes in the rear half of the lid. Ground the weld in the header and smoothed with sanding rolls. Lexx silencer with quiet core. All in all, well worth the money. Now I need my shocks to show up so I can start getting faster without feeling like I'm going to kill myself. The front shocks suck BAD.

the numbers are correct, its just that the dyno jet needle is much longer and tapered differently. Those numbers show the hole size for the jet.

[bearair]

Got in another good 2 1/2 hours today down South of here in the Owyhee ORV area (S/W Idaho). The throttle response is perfect. I can plonk around just above idle and hammer it and it responds immediately. No lag, no bog, just right. Power is improved everywhere, but especially off the bottom. It wants to loft the front end anytime I get on it in the lower gears now. I read the plug after the ride and I'm so close on the jetting I'm just going to leave it alone. The 146 looks to be the one for the current setup. I could probably go to a 150 in cool weather, but I'm going to leave it alone since it's only getting warmer now. In the fall I might step it up one when the weather gets cooler again.

The Lexx pipe is great. I'm running it with the quiet core and it's very unobtrusive. Nice and quiet when I'm trail riding and sounds nice when opened up. It's about the same noise level as the stocker at idle, and is somewhere in between the stocker and the stock pipe with the arrestor removed at full throttle and revved up. I think it's a great choice for staying legal in the ORV parks but keeping your power. Can't beat the price either. I paid $190 shipped. I'm well pleased.