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DIY Easy shift transmission mod


SlowMoe

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Alrighty! Just wrapped up the tranny mod on my bike s I figured I'd share the experience with everyone.

 

Ok if you're not familiar with this mod its purpose is to reduce the amount of missed shifts when shifting under power. I can't comment on its effectiveness but everyone who has had it done seems to think its very worthwhile.

 

I'm sure everyone does it a little different, but this is how I did it:

 

First you will need:

 

Digital camera

 

Paint marker

 

Rotary tool with some inch and a half or smaller cut off wheels

 

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Snap ring pliers

 

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Protective eyewear (Hopefully nicer than mine)

 

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Also leather gloves will come in handy when the part heats up. Don't forget a bucket of soapy water to rinse the gears off in after you cut.

Edited by SlowMoe
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Ok obviously first of all you need to remove the engine from the frame, tear the engine completely apart, remove both rows of gears from the cases and take off the bearings seals and stuff.

 

Now you need to dedicate one area to tearing down and storing your row of gears and another to grinding, to minimize contaminating your parts with shavings and such

 

Ok, first thing I do is take a bunch of pictures of both sets of gears from different angles, in case you forget how everything goes.

 

Next, take your first rack and set it in front of you as shown; take your paint marker and leave a marking on each gear on the right hand side, and on the end of the shaft. This will help you to know which way the gears go on the shaft if somehow you are lost and the pics don't help. Be sure to wipe the oil off the gear before marking

DSC00300.jpg

 

 

 

 

 

Next you pull the row of gears apart. What I like to do as I go is to slide the part (gear, washer snap ring) off and lay the right hand side of the part down on the table, so that when I put everything back together everything is exactly the same as before I took it apart. Start lining up your parts in order from the right to the left so that you know exactly what order to put it back together in. BE EXTRA CAREFUL because there are little thin washers that stay stuck to the gears and can fall on the ground and eventually be left out. Look at each side of each component good as they come out to make sure there isn't a washer stuck to it.

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Now that you are at this point, you know that everything goes back on the shaft from left to right, and that the side facing up goes on the shaft first. Be sure to take pics of everything lined up like this.

 

Now, what we will do here is take every gear that has 6 cogs and remove every other one, leaving 3. Gears with 3 cogs will not be touched.

 

Before

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After

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If a gear only has 3 dogs, leave it alone

So on this first rack, there will be 2 gears total that you will be grinding on.

The first one I grab is the one to the left. I begin by chopping off the protruding chunk of cog as shown in the photo. Use the least amount of pressure that your patience will allow you to keep from heating the gear too much. Be patient and pay attention to what you're doing so you only cut the cog you are working on.

DSC00309.jpg

 

 

 

Once you have lopped off the big piece, skip a cog and cut off your next one. The reason I don't completely remove a cog at a time is I don't want to localize the heat too much.

Now after you do all 3 you should be left with something similar to this:

DSC00310.jpg

 

Now once you have the big cuts done go ahead and feather out the remainder of the cogs until you're left with this:

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Once you've completely removed all 3 dogs from the gear, go ahead and wash it real good in soapy water and wipe off all the trash and shavings. Put it back where it was in the lineup and do the other one. Once you're done with that one reasemble the row of gears and do the next row using the same steps outlined here. I believe the other row has 4 gears total that need grinding.

 

It will take you 15-25 minutes per gear so be patient and PAY ATTENTION to what you're doing. It can get monotonous and you don't to veer off and cut a good cog all to heck. If you do cut somewhere not intended I suggest you blend the the nik into the parent metal at a 3:1 taper to eliminate any stress risers. Make sure your area used for cutting is well lit.

 

I believe that's about it. Make sure you wear your safety glasses because 30,000 RPM + shrapnel can be bad news for your eye. A face shield would probably be a good idea as well.

Edited by SlowMoe
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It increases the chances of the cog of the "male" component landing inbetween the gogs of the gear to be engaged instead of on top of them, which is typically what happens when a shift is missed.

 

 

And Tedd, you think that 150 degrees f is enough to make a gear lose its tempering?

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