(These steps also used for chain replacement of course)

The 30t sprocket is ORIGINAL  so your dealer CAN get them.
It's really not expensive, and well worth the money.

We'll assume you know how to use a wrench, and have the standard tools for the job. The only special thing you'll need here in a chain link tool
This is how one looks:



and also a pair of one hand-grips (see photo further down), to help with putting the chain back on.

Get it on!

First thing is to remove the chain guard and the chain cover, that is real easy and you end up like this:



 Might be a good time to clean your bike before you continue...
Also check out the chain tensioner



Ok, a quick cleanup and we move on...



First we need to remove the chain. BEFORE doing so, check if your chain already have been changed and may have been put back on with a CLIPS LINK. (Mine was)   If so, we can reuse this, or you go a buy one. The chain on a Spyder is a very high quality #520 "O" - ring chain, and you should be able to get a clips link everywhere.
Some people don't like the clips links, since they in theory could open up while driving, but I've already done 3500km on my bike with one on, and never had a problem - so I'm not so scared of them.

Here you can see the clips link:



I remove the clips and the chain is apart, note the little "O"-ring's - don't loose those ;-)



I clean the chain with WD40 and wipe it down. Before moving on check your chain tensioner is working right, and the spring is alright.



Mine was alright, but the nylon wheel could use a replacement some day - I'll keep it in mind ;-)

Also take note of the wear on your front sprocket



Now, since the new 30t sprocket is smaller in diameter than the old 34t, the chain needs to be shorter. One link must be removed with the tool I showed above. This was fairly easy, and done in minutes.



Now comes the hard part.
Since I don't have a real MC lift, I need something to lift my bike of the ground so I could remove the rear wheel. I tried with some straps in the ceiling of my garage but it didn't work very good. So i finally got my old carjack out ;-)
I strapped each handlebar to lock the front end in place.
Then I put the jack under the bike and lifted it up while holding the bike with my other hand. Putting a wooden board under the bike and stacking some stone under it until the height was right. Then lowered the jack and I was ready to go.




Removing the center pin that holds the rear wheels is not the biggest thing, but note that there is a loose "plug" that goes in the hub seal in each side of the rim, they'll fall out most likely, so don't get them dirty.

Once the wheel was on the ground, I when removed the rear brake caliper (might not be nessesary but make it MUCH easier to get the wheel back on again)



Now I removed the old sprocket, and put on the new. No big deal.
Here's the new sprocket on top of the old one, so you can see the difference.



Then I put the rear wheel back on, and finally the rear brake caliper back in place.

 Finally  pop the clip link in (REMEMBER THE O-RINGS) and put the clip in to lock it.
Very important - the clip must go the right way on to ensure it don't fall out when the chain is spinning at high speed. (open end of clip faces opposite to rotation)

Look here bro!



See the clip kinda like facing in the chains driving direction like a little arrow? well, maybe you don't but this is how it must look. ;-)

Ok. Put all the covers and sh** back on the bike and get it back on the ground. Maybe you want to lube the chain a bit while you have it jacked up anyway (much easier). I sprayed chain lube on the inside of the chain, just below the new rear sprocket. This is really the only place you need to lube a o-ring chain.