2009 yz450f JD kit help

3 replies to this topic
  • MtnMaster

Posted April 01, 2013 - 10:57 AM


I bought a 2009 yz450f used just a few days ago. Owner says it has a JD jet kit in it, but he had the dealer install it and knows nothing about it. Does anyone have a kit with the instructions, so I can see about where I'm sitting. The original owner rode at around 2000', and I will be around 3,500 and higher. I'm going to open up the carb, and see what's in there, but would like to know what the kit recommends.
Dr.D full system, all else motor wise is stock.
If anyone could help me out, it would be greatly appreciated.... Also, going to check if they did the accelerator pump mod.

PS. I searched the stickies, but didn't find much.

  • FinchFan194

Posted April 01, 2013 - 03:20 PM


Call JD and talk to Dave, he will be able to answer any and all questions better than anyone here.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • MtnMaster

Posted April 02, 2013 - 09:17 AM


more than anything I just want to know what the elevation between the needles. It has the red one in it..... 3,000 feet+

  • vic2340

Posted April 17, 2013 - 04:38 PM


If the bike is stock set the bike to stock jetting and go from there. I have an 09 yz450f and it runs great maybe even better than the most new efi bikes. I cant get it to bog, throttle response is crisp and no backfireing. When I first got it it popped on deceleration very badly, bogged, and if you gave it to much gas it would shut off, the jetting was set up by the very badly by the stupid previous owner. First things first I say GET A SERVICE MANUAL. Make sure your accelerator pump is adjusted to the stock specs. (if you want me to tell you how to do this I can).I also put an o ring around my accelerator pump arm to hold it in place (its called the o ring mod, its very common and very effective.) My bikes main is 160 (stock) pilot is 45 (stock) leak jet is 55 (stock). The other jet next to the pilot called the pilot air jet is 100 (stock) the last jet that no one knows exists is the starter jet and mine is 72 ( also stock) And finally my fuel screw is turned out to 2 and 3/8 turns (1 and 1/2 being stock), I saw an article in motocross magazine to adjust the fuel screw to that setting and it truelly does work the best. My needle clip is the only thing besides the fuel screw I needed to adjust from stock to get my bike running perfect, its at the 4rth position instead of the 3rd. I adjusted it when my bike was hesitating in the mid range rpm's. I am below 3,000 feet in elevation. If your 2009 yz450f is stock and also is below 3000 ft in elevation I highly recommend you mimic my jetting. It made my bike godly responsive like and efi bike. If you need any help please feel free to ask me I can tell you how to do everything step by step.

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