04 wr450- gearing for high speed- please help


10 replies to this topic
  • woodsedge

Posted August 28, 2004 - 02:38 PM

#1

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.

I 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.

  • Dan_Lorenze

Posted August 28, 2004 - 03:18 PM

#2

Wood, go for the 15 tooth counter sproket. The bike still pulls down low and increases your top speed. I've always prefered changing the counters, they're cheaper and quicker to change, Good luck at your race. :thumbsup:

Dan

  • Radbuster

Posted August 28, 2004 - 04:59 PM

#3

It should top out right below 100 w stock gearing if the free mods are made. 5th is pretty tall, but two down on the rear or 1 up in front should make it plenty tall and keep the revs down at the speeds you are looking at. Any Baja gurus out there?

  • iNSaNe

Posted August 29, 2004 - 01:50 AM

#4

It will top out around 92-93MPH stock. Any more is not possible mechanically :thumbsup:

If you use the Gearing Calculator, I believe you need a 15 tooth front sprocket or 45-46 tooth in the rear to be able to hit 100MPH.

  • iNSaNe

Posted August 29, 2004 - 03:19 AM

#5

Gearing info from the manual

Primary reduction system Gear
Primary reduction ratio 62/22 (2.818)
Secondary reduction system Chain drive
Secondary reduction ratio 50/14 (3.571)
Transmission type Constant mesh, 5-speed
Operation Left foot operation
Gear ratio:
1st 29/12 (2.416)
2nd 26/15 (1.733)
3rd 21/16 (1.312)
4th 21/20 (1.050)
5th 21/25 (0.840)

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  • Racer577

Posted August 29, 2004 - 06:59 AM

#6

I just did a track day on my 03, with 19" DT tires. I used 14-37 and it worked well. It would probably top out just over 100 at 5000 ft. a 14-39 probably would have been perfect since with the tall gearing it had trouble with the 4 to 5th shift if you were not wound out in 4 th. I had run 15-45 previously ( still fits with same chain that fit 13-51) and I could not pull redline in 5th, but the bike lacked top end. I think you need to be geared a little taller than the bike can pull to redline since the power seems to drop off a little at high rpm.

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.

I 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.



  • firestarter

Posted August 29, 2004 - 09:14 AM

#7

I just did a track day on my 03, with 19" DT tires. I used 14-37 and it worked well. It would probably top out just over 100 at 5000 ft. a 14-39 probably would have been perfect since with the tall gearing it had trouble with the 4 to 5th shift if you were not wound out in 4 th. I had run 15-45 previously ( still fits with same chain that fit 13-51) and I could not pull redline in 5th, but the bike lacked top end. I think you need to be geared a little taller than the bike can pull to redline since the power seems to drop off a little at high rpm.




:thumbsup: &%$#@!?

  • Racer577

Posted August 30, 2004 - 06:45 PM

#8

The guy wanted to know high speed gearing for a WR. I have raced mine on a road race track, probably 110-115 top end. Ran the 14-37, I also ran the 15-45 on the same track but not fast enough, I really got left in the straights by everyone. The stock gearing is not nearly fast enough for long dirt roads. In moab the stock gearing topped out at low 90's and the bike is wound out pretty good cruising at 70 or so on the road. I would run 14-41 or taller if I had to run a lot of roads and wide open stuff. If I had to do some tighter stuff and roads I would run the 15-45. I ran 14-47 at bike week in daytona and it was still geared way to short. First was useless on the street and the bike would still wheelie at 55 in 3rd.

I just did a track day on my 03, with 19" DT tires. I used 14-37 and it worked well. It would probably top out just over 100 at 5000 ft. a 14-39 probably would have been perfect since with the tall gearing it had trouble with the 4 to 5th shift if you were not wound out in 4 th. I had run 15-45 previously ( still fits with same chain that fit 13-51) and I could not pull redline in 5th, but the bike lacked top end. I think you need to be geared a little taller than the bike can pull to redline since the power seems to drop off a little at high rpm.




:thumbsup: &%$#@!?



  • OrionEngineer

Posted August 30, 2004 - 09:48 PM

#9

Check this thread out:
http://www.thumperta...rue#Post1288254
You can download my gearing calculator and decide for yourself!

  • Vick115

Posted August 31, 2004 - 10:14 AM

#10

I have 03 WR450 geared for street use, I have a 15/45 setup and its good for 100mph. Still will do a 3rd gear power wheelie easy.

  • jchantzWR400F

Posted September 01, 2004 - 10:54 AM

#11

I was running a 15/44 combo. Worked very nicely on the street. 70 mph crusing at respectable rpm. Nice 3rd gear power wheelies. Would have easily hit 100 if I would have had balanced tires.




 
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