Gearing 05 YZ450F

The 05 YZ came with the old 4 speed gear box. The stock gearing is setup as 14/51.. I am currently running a 14/48. I feel when I put it in 4th the bike lugs and takes to long to get up in the powerband in order to clear a triple of something.

I was wondering what most people run with this year bike? I mostly ride track and race GP.

Well you did essentially make the bike have taller gearing so its going to have more top speed than stock but less acceleration.

What was wrong with stock?

I cant help you out with any suggestions as im on the other end of the scale (low gearing for tight trails)

The other day i was out at the track and in order to clear some of the bigger jumps i needed to be in 4th gear. The problem I was having is that when i got the bike in 4th gear the bike would would be lugging and would take to long to feel any kind of acceleration in time for the jump.

Just trying to find out what others on here have good success with. The stock gearing made first gear useless. With GP racing in southern california you need some good top end for some of the long open roads. Basically im trying to find a good middle ground to where I have fast acceleration and have more top end than stock.

How big is the jump that you need to hit it in 4th with that gearing? I use to run similiar gearing on my 04 and don't think I ever got into 4th on a mx track. I love the 4 speed but it is difficult to find a gear that will work on the MX tack and also off road. By the way if it lugs you are not winding it out in 3rd far enough. My 4 speed would still wheelie shifting into 4th with a little tug on the bars.

Its a triple which im gonna guess it is about 60 feet at least maybe more. Kinda of hard to guess what it actually is. the other is a huge table top close to 80 ft

For one thing, you are geared 3 teeth higher than stock. Besides raising your top speed, this has the effect of widening the gaps between each gear, so that may be a good part of your problem. Either ditch the 48 and put the 51 back on to start with, or replace the 14 with a 13. You may end up with a 13/49 for some tracks.

Inasmuch as 3rd gear with stock gearing will produce roughly 50 mph on the power peak, it does seem odd that you'd need 4th for a 60 footer.

I could be wrong about the size of the jump. Like I said it was just a guess. It probably is longer than 60 ft. I think I'll swap for a 50 and see how that works for now.

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