Installing new rear end gears-STEP BY STEP w/PICS, and performance results!

[scootnfast]

Well, I am going to start making a habit of posting all the mods I do to my scooter. With step by step instructions on how I did it, and the results of my work. First of all, let me start with the general disclaimers.

1. If you haven't de-restricted your scooter, Click here to see how to do it here : http://www.apriliaforum.com/forums/s...&threadid=8617 Also, if you are curious as to how roller weights, variators and contra springs work, Click here: http://www.apriliaforum.com/forums/s...3637#post63637

2. If you tamper with the motor in any way to de-restrict it, some dealers will completely void your warranty. So make sure this is a sacrifice you are willing to make.

3. ALL bolts and socket head cap screws are in metric! Don't try to work on your vehicle if you don't have metric tools, you will just end up messing up the heads.

4. This entire installation (Although it seems rather complex), took me only about 1 1/2 hours to complete from start to finish. It is rather simple to do, but it is a bit involved.

This posting is how to install new rear end gears.

The purpose of these gears is to give you more top end, while at the same time not changing your acceleration. The peak horsepower of you engine is generated at about 8000-8500 RPM. Stock, you are doing about 8500 RPM at 40-45MPH. From then on, you are increasing your RPM's, and decreasing your horsepower. The gearing just uses the full potential of your variator, and makes it so when you are at 8500 RPM your peak horsepower, you will be going 50-55 MPH instead of 40-45 MPH.

Lets Get Started!

[scootnfast]

First start by removing the cover off the left side of you scooter.

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This is what you will see behind the cover:

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Remove the bolt holding the clutch assembly on:

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Remove the Clutch bell housing and the clutch assembly with the pully:

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Remove the drain plug, and drain the oil from your tranny. There isn't much oil in there, so it doesn't take very long.

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Next you have to remove your exhaust to remove your rear tire.

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Remove the two bolts holding on the brake callipers. I found it extremely difficult to actually remove the callipers from the disk. So I just left the callipers on the disk. There is enough hose that you can remove the tire without having to take the callipers off the disk.

[scootnfast]

With the exhaust removed, remove the cover on the back wheel so you can get to the bolt holding it on.

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Remove the bolt holding on the rear wheel.

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Remove the entire rear wheel from axle. Then remove the bolts holding the tranny cover on.

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Once the covers bolts have been removed, gently pry the cover off. There is no gasket around the edges, there is a large o-ring instead. Be sure not to damage this when removing the cover.

When you pull the cover off, be careful not to drop any gears or washer shims. YOU WILL NEED TO RE-ASSEMBLE THE GEAR BOX EXACTLY LIKE TO FOUND IT. There may be several washers that are on different gear shafts. Don't loose them or mix them up! Be sure to note where each one was located.

[scootnfast]

Once the tranny is off, you will notice a large gear, with smaller gears located behind it. Just pull these gears out gently. They will simply slide right out.

[scootnfast]

These are the gears you should have pulled out.

[scootnfast]

Now for the most difficult part. You have to press the gear off its shaft. You can use a gear puller (Not an easy task), or if you have a heavy drill press, put a large socket behind the gear, and use the bottom of your drill chuck to push the shaft out of the gear.