I have an 05 CRF450X. It was way too lean out of the box, just like all modern 4 strokes are, and have been for a long time. I'd read so many good things about JD Jetting I decided to install their kit first thing. I've been riding a long time , but am no jetting expert, so why not give them a go. First let me say this company returns e-mails, answers their phone, and are not condescending at all.A real pleasure in this "I want to avoid human contact" business world. I followed their directions exactly. Their web site shows clearly how to open up the side vents, and has many other helpful tips. With stock exhaust they recommended 1 and 1/8th out on the fuel screw, and to use the red needle. Wow. There is NO bog, whack the throttle open as hard as you like.There is no back-firing. The bike starts up instantly, and wams up way quicker.It pulls very strong through the gears. The spark plug is a beautiful tan. They include a bunch of extra mains and a cold wether needle, too. What more can you ask ? I highly recommend the product, and applaud their personal and friendly customer service. Doug Benton
Installed kit easily. Took about 30-45 minutes. I had never rejetted a carb. Directions were very clear and easy to follow. Results are incredible. The bike runs much cooler, doesn't stall easily and throttle response is great. Best mod I've ever done!!
Installed this kit along with an accelerator pump upgrade kit, leak jet, Merge racing ap spring, and crf fuel screw. What a difference! The bike pulls much harder from idle through the rpm range. I no longer have the dreaded 05 450x bog off of idle, only instant throttle response and smooth acceleration. The jetting instructions were spot on. My jet kit came with the wrong instructions and Ken promptly emailed the correct instructions and verified I had the correct parts in the kit for my bike. Excellent kit with excellent service from CRF's Only. Highly recommended.
Installed on 07 crf 450x the directions were simple to follow and the improvements were excellent form idle through top end .I opened the airbox sides as directed and put on fmf q4 silencer and the bike runs great.I would recommend this product to anyone it solved all my problems with the stock settings.
2007 CRF450X. Got good results from the kit. However, kit worked best with an adustable fuel screw mod too. Thew instructions were pretty good. They said fuel screw adjustment and accelerator pump o-ring mods were not applicable to the 2007. But, they were in fact needed. Both were subsequently performed and worked. The 2007's fuel screw requires a special "D" socket. I was able to get mine out with a pair of tweezers after removing the carb from the bike. JD Tech support was slow via e-mail. Got better support from the 450X on-line forum.
BEST money I've spent in a long time!! Bike idled poorly, was impossible to kick start, and would often stall out. This kit fixed it all and the bike runs great!! Easy to install...only tricky part is getting the O-ring around the linkage...used a metal coat hangar with a small hook bent at the end....was easy from there.