08 400ex help. wont run

[atvdreamer69]

ok ive changed a few things around but it ran last weekend. went to get it loaded today and it wouldnt start. it will fire for a second and die, each time you fire it up it runs a little longer untile it will finally idle with the choke off but when i give it gas its like its flooding it or something because it moves a little and sputters and dies. i dont want to take it to the honda shop but im out of ideas. ive added a modquad air intake with k&n filter, lexx slip on with 40mm open tip (w/spark screen). ive got a big gun box but haven but it on yet because the quads not running right and i dont have my tach gage yet. could this be a jetting issue? i havent touched my jets yet still factory size:confused:

[jcs003]

starting issue is related to your pilot jet. but with the modifications you got other jetting changes may be necessary.

[atvdreamer69]

ive got new jets here right now. i got a 40 and 42 pilot and a 150, 152, and 155 main jet. im going to use the 40 pilot but should i skip the 150 and just try a 152 with my mods? will the rev box effect my jetting?

[jman7290]

Try flipping your fuel petcock up to researve and see if it will run. If so you need to clean your fuel petcock, that happens to mine all of the time. As for your jetting, when I first started my mods, I did all of the same things, Air filter, air box, full exhaust, rev box, etc, and it ran fine with the stock jetting. I did bump it up to a 150 main jet to be safe,( if you add more air you need more gas so it dont run lean and burn a hole in your piston), and it ran great. I would not go much bigger than that untill after you do a cam up grade, head work, and or a bigger bore.


05 440 11:1 Big Bore, Hot Cams stage 2, GT Thunder HD studs and HD timing chain, Ported & Polished, Trinity stage 4 full exhaust, Doug Eichner signature series 440 carb with billet spacer plate, AMR stage 3 CDI with Monster Coil, Uni Filter with Pro Design Billet intake adapter and aluminum air box with scoop and outerwear, over sized aluminum oil tank wih air ports, Elka Elite front shocks with Full Flight +2 A-Arms, LoneStar +3 axcalaber axel with billet twin row bearing carrier, LSR brake block off, ITP Rims, DG Fat series swing arm skid, DG Race Peg nerf bars, DG V-Lite front bumper, DG case saver, OMF air scoops, Rox dash panel and hand gaurds, Precision steering stabilizer, Fasst Flex bars, ODI Grips, Outerwears shock covers

[clemsonteg]

Starting could just be from the hard start, mine does it if its cold. If its nice and warm outside it usually does better. As far as the jetting, it depends on your climate and altitude. With just a slip on and a filter you can be anywhere from stock to a 155. With the airbox lid removed or modified it could go as far as 160 or so. If I were you I would stick in the 155 to start and see where you are. If it runs fine and the plug looks good then leave it or if it sputters at the top end try the 152. Its better to be a little rich than lean.