Gearing for racing 04 YZ450F


10 replies to this topic
  • Streamline

Posted March 04, 2011 - 03:39 PM

#1

Right now I have the stock gearing with 14/48

Also, the 04 is a 4 speed so they are long gears.

I'd like to change the gearing a little bit as I'm racing a lot of desert races in the AMRA series in AZ. Lots of single track/tight stuff. I've been having trouble with stalling in the tight stuff/some hills and I really don't even get much of a chance to get into 4th in this series.

I'd like to be able to use the same chain length as I also race a lot of Grand Prix races/some MX. So I'd like to be able to switch back and forth.

Any help would be wonderful,
Tyler

  • grayracer513

Posted March 04, 2011 - 03:53 PM

#2

With the '04, you can, depending on where your axle is now, often shuffle front sprockets around. You could use a 13/48 for your technical races, then back to stock, or even 15/48 for the open desert. I used to run 15/49 on my '03, and it worked pretty well.

You should definitely add flywheel weight if you haven't done so.

Another much more expensive but very effective option is the Rekluse Z-Start Pro clutch. Once set up, it all but eliminates the problem of stalling in tight spots due to high strung engines and tall gearing.

  • Streamline

Posted March 04, 2011 - 04:09 PM

#3

With the '04, you can, depending on where your axle is now, often shuffle front sprockets around. You could use a 13/48 for your technical races, then back to stock, or even 15/48 for the open desert. I used to run 15/49 on my '03, and it worked pretty well.

You should definitely add flywheel weight if you haven't done so.

Another much more expensive but very effective option is the Rekluse Z-Start Pro clutch. Once set up, it all but eliminates the problem of stalling in tight spots due to high strung engines and tall gearing.


I was hoping you'd reply, I went ahead and went with the Regina 520 ORN6 O-Ring Chain 520x114 that i believe you suggested a while back. It's a great chain. How much of a difference will a 13 make? I don't know very much about sprockets.

  • grayracer513

Posted March 04, 2011 - 05:18 PM

#4

Only about 5/16 - 7/16" at the axle, but one tooth at the fronts changes the gear ratio as much as 3 at the rear.

  • Streamline

Posted March 04, 2011 - 05:35 PM

#5

Only about 5/16 - 7/16" at the axle, but one tooth at the fronts changes the gear ratio as much as 3 at the rear.


So will that push the axle back or bring it forward? Also, by removing 1 tooth in the front, is that the same as removing or adding 3 in the rear?

When it comes to bike set up I'm a little "slow". :thumbsup:

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  • baxterj787

Posted March 04, 2011 - 06:15 PM

#6

Taking away teeth from the front gives the same result as adding teeth to the rear. Either action will move the axle FORWARD in the swingarm.

As Gray said, the FWW is an excellent modification to the 450.

  • Streamline

Posted March 04, 2011 - 06:24 PM

#7

Taking away teeth from the front gives the same result as adding teeth to the rear. Either action will move the axle FORWARD in the swingarm.

As Gray said, the FWW is an excellent modification to the 450.


Thanks, that's what I thought but I wanted to make sure. What are the benefits of adding FWW?

  • grayracer513

Posted March 04, 2011 - 06:43 PM

#8

Either action will move the axle FORWARD in the swingarm.

Pardon me? You were good until you got there. Reducing the number of teeth on either sprocket will cause the axle to move BACK, not forward.

To gauge the amount, take the number of teeth times 5/8" (.625) to get get the change in sprocket diameter, then divide that in half since the chain runs over only half the cog.

  • Streamline

Posted March 04, 2011 - 06:53 PM

#9

Pardon me? You were good until you got there. Reducing the number of teeth on either sprocket will cause the axle to move BACK, not forward.

To gauge the amount, take the number of teeth times 5/8" (.625) to get get the change in sprocket diameter, then divide that in half since the chain runs over only half the cog.


Thanks for clearing that up! I'll need to check my bike after I get off work tonight then as I think my axle is pretty far back already...

  • baxterj787

Posted March 06, 2011 - 06:11 AM

#10

Sorry guys. I had my head waaaaaaaay up my, well nevermind. Gray is right on the money.

I will now try to remove my head from where it is.

Sorry again.

  • Streamline

Posted March 29, 2011 - 10:10 PM

#11

Pardon me? You were good until you got there. Reducing the number of teeth on either sprocket will cause the axle to move BACK, not forward.

To gauge the amount, take the number of teeth times 5/8" (.625) to get get the change in sprocket diameter, then divide that in half since the chain runs over only half the cog.


I had another question for you Gray if you could give me some help? I've been having some major problems getting my bike restarted during a few of the races. This last one it died going into a silt section (not sure why/just cut out) while I had the lead and it took me 6 minutes to get it going again, ended up last in my class for that GP. It's done the same thing back in January I believe and took me a good 8 minutes to get it started (also in the lead). I almost missed a Night MX in December (missed the 15 min practice) b/c I couldn't even get it started off the truck.

I'm thinking jetting but when it comes to this stuff I'm lost. I race all over AZ for fun and I have a fuel screw I can mess with but if you had a good place to look for a in depth walk through or just some good advice that would be wonderful.





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