I have a recently broke in 2009 WR450F. I’ve done the grey wire mod, throttle stop mod, and replaced the stock tail pipe with a larger diameter Yamaha tail pipe.
The last time I had the bike out it over heated (I was on a steep rocky trail). I’m a newbie, so I’m guessing my crappy technique contributed to the problem, but after doing some reading on this forum I believe I need to make some changes to the carburetor.
To be honest with you I’m not much of a mechanic. What I know about the bike I’ve learned from this forum, my manual, and from talking to a few friends. I’ll apologize in advance if I repeat a question that has already been asked, or if you are just annoyed with my ignorance.
Here is what I think I know, please correct me if I’m wrong. Due to the mods I’ve made, and the elevation at which I ride, I need to re jet the carburetor. I will need to look at the jetting tutorial here on the forum to get an idea of what size jetting I need to use, according to my elevation. I’ll need to purchase a jetting kit, adjustable fuel mixture screw, and a needle kit (JD Needle Kit). I’ll start with following the procedure I found here for “Selecting the Correct Pilot Jet and Setting the Fuel Screw”.
Ok so here’s what I don’t know. While following the procedure for selecting the correct pilot jet and adjusting the fuel screw, do I need to be at the elevation I’ll be riding in? Also, this procedure refers to the settings in the book. My book lists no settings, or a procedure to adjust the fuel screw. In the jetting tutorial, the author recommends a JD needle kit, which I couldn’t find on the JD site, does it exist?. So here is probably the most newb-ish question. I see in the jetting database all different size jets. I took a look at the JD jetting kit for my bike and it doesn’t list various sizes, just that it accommodates elevations from 0 to 12000 feet. I’m assuming it comes with an assortment of sizes, right?
Am I leaving anything out? I would like to thank you in advance for the help. This is a great forum, I’ve learned a lot already from you. Any other help would be appreciated.