I installed the DG snorkel, Twin Air filter, and DynoJet kit, and I’m having a problem. I went with the 128f, 132r, 4th notch on the needle, with 2 washers, and with 3 turns out on the air/fuel screw. It starts fine, and idles fine, but after about 1/3 throttle it starts to “blubber”. It runs fine if I choke it a little. So do I go up on the main jets (130f, 134r), or try the 5th notch on the needles like DynoJet recommends? I tried adjusting the air/fuel screw, but it’s not enough. I’m at about 500’.

 

You are lean, it's because of the DG snorkel flowing so much more air, leave the air screw's at 3 turn's. and the needle's at 4th notch, I would jump all the way to the 132 and 136 main's and see how it run's, I would bet those will work, if it load's up at full throttle then drop back to the 130 and 134 main's and you'll be O.K. better to be a little rich than lean and you are lean if it run's better with the choke on a little.....

 

I just finished rejetting my 650 again. I am using DiamondG snorkle, K&N filter, & BigGun exhaust. I went with the 4th pos on the needles and 132 f/136r. I also encountered a "blubber" at probably around 2/3 throttle. It would continue to backfire and miss as long as I held that speed. If I continued excelerating it would be fine. I just installed 130f/134r and now it runs perfect throughout the power band. After the engine warms up I have problems keeping it idleing and have had to turn the idle up. My fuel mixtured is turned 31/2 turns out which helped it to start easier. Good luck on finding correct jets!

 

I went up to a 130f and 134r (before I read your post Stakk). It coughed a little when it was cold, but doesn’t when it’s warmed up. It doesn’t have the acceleration that it did before the mods, and there is a hesitation when I hit the throttle. Choking it doesn’t make it run any better now (like it did with the 128f, 132r). I’ll try going up to the 132f and 136r to see if I can get my acceleration back. I’m wondering how other people are getting away with a 128f and 132r with the same mods I have. They must be at higher altitudes than 500’.

 

I have rejetted my quad several weeks ago. I ran it against some quads I have always raced in the past. It ran fine thru out the full trottle race ( no boggy, flat spots ect. ) except I did not pick up any speed. Today I played with the fuel mixture screw and saw slight improvement running it in my yard. I will be getting my Carbtune II kit to synchronize the carbs this week. I have 132 front and 136 rear jets from Dynojet. From reading posts I see my jets size is higher then most everyone else. What else can I do to get more speed. Higher jets? Lower jets? Any help greatly appreciated.

 

650vtwin, i get the same blubbering problem. let me know if you find a cure, i will also...

 

I’m up to a 132f and 136r, and I still don’t have the torque or top end that I had before the intake and air filter. It’s better than the 130f & 134r, but I’m still about 20 km/h slower on the top end. At least the initial hesitation is less noticable. I talked to DynoJet, and they said to go up one more size to 134f and 138r since top end is the Main Jet only. Hopefully that’s enough, because the jets don’t go any higher.

This doesn't seem right. Any suggestions?

 

What gains should we expect if we move the needle to the 5th notch?

 

I must have had something hooked up incorrectly. I think the diaphragm wasn’t properly sealed and there was some leakage (of air that is). The 132f, 136r, 4th notch, and 3 turns out work great. I didn’t loose any top speed, and I gained more torque.

Haynes – Personally, I didn’t notice any difference between the 5th and 4th notch. I tried both, and couldn’t tell the difference. I don’t have any hesitation with either setting, and plugs are a nice light brown.

 

I just got done jetting mine. I started on the 6th notch, went down to 5 and ended up on the 4th. There was a difference between 5 and 4 on my machine; I had a slight bog when going from 1/4 throttle to 1/2 throttle and from 1/2 to 3/4 throttle. No bogging on the 4th notch. BTW, I've now got a Supertrapp IDS-X w/12 discs in, Twin Air filter, Dyno-Jet kit and 5 one inch holes in the airbox cover. Also running DJ136 and 132 mains.