OZ ATV :: The Australian ATV Forum

[ozzybloke01]

I have just bought an 07 YFZ450 for my son which is running 14T fr and 38T rr sprockets but as we do mainly bush riding we would like to give it a bit more legs could someone plz give me advice as to which sprockets I should change and to how many teeth to achieve this....thanks heaps Ian
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My ride...
09 Raptor 700

My boys ride...
07 YFZ478 (yep big bore kit)

[dangerman4]

what condition are the front and rear sproket in?
most people go to a 15 front which will give you another 10 - 15 kph but it will take longer to get there.

[shreka]

Depends on wot other mods you running ? I have 07 YFZ450 run a 15 up front and a 36 down the back run this setup for bush riding and most of the pony express rounds last year with no problems. Bike has Pipe, Jetted, and after market air filter, also done the cam mod. Im also in Bunbury so give us a PM maybe go for a ride some time...

Cheers

Regan

[bigjon]

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Don't close your eyes during the crash, you'll miss the best part

[bullet]

One thing i don't get is how a lot of people say gearing down gives you more bottom end and gearing up gives you more top end.
This is not correct.

If in top gear you reach the rev limiter before you reach top speed, then gearing up might enable you to go faster.
But if you gear up too much, your engine power might not push it, and you might actually go slower.
Most modern cars will go faster in 4th than they will in 5th, because 5th is too high for max speed.
a classic case of where gearing up made the car go slower (in that gear).
They keep it up there because it is a cruising gear and some emmisions are measued in grams per 100km, so less engine revs keeps that down too.

Gearing down will reduce the gaps between gears (close ratio) and may give you better gear ratio choices for different hills and corners etc.
Instead of revving in 3rd or chugging in 4th etc.
It will reduce top end because you will most likely bounce of the rev limiter well before your top speed and run out of gears.

I have geared speedway quads up to a theoretical top speed in 5h of 170kmh when the bike would only be raced at 88kmh.
because i wanted a higher 1st gear to take off in, less gear changes and run the track in 3rd.
As one of the fasterst bikes on the track, it would not pull top gear down the beach.
But in this case, gearing up made the bike significantly faster.

There are otherexamples where MX racers are doing the opposite and taking off in 3rd gear, for max acceleration to get the holeshot, and sometinges they do.
They do not gear down for more bottom end, and in fact they never use their lower gears on the track.
They gear down to go faster... in their application.

So i gear my DS down to race MX with a top speed of 110kmh and gear up to race speedway at only 88kmh.
In both situations track times and therefore acceleration is improved.

Changing your gearing does not effect your aceleration at all.
Only acceleration in top gear... but then just go back to 4th and accelerate even harder if you want.

Only your engine power and how you use it effects your acceleration.

Having said all that...
If you have done an exhaust and the usual mods you are probably making 10% more power, so for general riding a 10% gear up also makes sense.
Your 'new' power will push the 'new' top gear.
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Can-Am X Team
Bullet #Y12. MrsB #Y18.