2009 WR450F Newbie Carburetor Questions
Posted August 31, 2012 - 06:08 PM
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.
Posted September 01, 2012 - 02:52 AM
Along with jetting, I highly recommend a high pressure radiator cap (30psi) to replace the stocker. This will allow much higher temperatures before boiling over. Your still using the catch tank, right?
Posted September 01, 2012 - 06:04 AM
Posted September 01, 2012 - 07:57 AM
It sounds like the JD kit is the way to go then, the chart would be very useful. How about the needle kit, ever heard of such a thing? I will start looking for a new radiator cap as well. Are there any disadvantages to going with the higher rated cap? Seems like a good thing to me, if it keeps your coolant from dumping on the ground. I am using the catch tank, but in the heat of the moment I didn't even think to look at it when it happened. By the time it occurred to me to look, after 10 or 15 minutes of letting the bike cool, it was empty. So I'm assuming it was full, and dumped the excess on the ground? How was Baja, any problems with your bike? I'm hoping to get familiar enough with my bike to take a long trip like that one of these days, sounds like a lot of fun!
I've also been thinking about installing a radiator fan. I was eye balling it last night, and was wondering if I could get one to fit. It looks pretty tight between the tank and radiator. Do you use the stock tank? I'm using the stock tank for now, but I'm considering moving up in size. I'm guessing the clearance would be pretty close to the same for most of the after market tanks?
Thanks again guys, I appreciate your help.
Posted September 01, 2012 - 08:54 AM
Posted September 01, 2012 - 09:42 AM
You think a main jet would do the trick? I think the elevation is about 2000 feet where I ride, but we climbed maybe another 1000 feet or so I think. Are you familiar with Harris Park in Milton Freewater, OR? I'm not exactly sure what the elevation is there, but that is where I was when she over heated.
Posted September 01, 2012 - 09:57 AM
There is no such thing as good jetting for 0-12000 feet.
You change the main jet for every 2,000 feet or 25 degrees. That is super impractical for most people, so you try to get it close, and these bikes are very forgiving of incorrect jetting.