New 04 WR450- jetting for low and really high altitudes- please help

I just got my new 04 WR450 and I need to set it up for a rally race in Ecuador. I have never owned a Yamaha at all so I don't know the tricks.

The rally is 6 days of racing, 2000 miles. Mostly dirt roads with some pavement thrown in. Also from sea level to 15,000 feet elevation. And high speed, very high speed.

So far, all I have done is put in 1 size larger main jet and raised the needle 1 ring, and pulled the baffle (I hate loud bikes, but I'll deal with that later). It has a bad stumble and runs rough in upper midrange. Recommendations for sea level? For 10,000 feet? For over 10,000 feet? I will disconnect the grey wire also.

I also need to make sure the bike finishes this race. What do I look out for? Bolts that especially need locktite or safety wire? Things that break? Anything?

I also need to change the gearing. I have already changed the front sprocket from 14 to 15 teeth, but think I need more top end. I would like it to top out around 100mph. Anybody know the gearing for 100?

Thanks in advance.

15/50 tooth will get you at 100 but you should go for the 16/45 tooth to avoid blowing up the engine. Jetting for all conditions is hard so I would recommend leaving it stock so you are not to rich at 15,000. feet! The bike stays pretty tight as far as bolts loosening they happen occasionally but nothing that is repetitive that I can point out. Good luck with the event! :thumbsup:

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