919 front sprocket install
Zookmor did this write-up for me when I bought his 15t front sprocket.
Wanted to post it up for the next guy....
I would consider myself a moderately mechanical amateur at best. I have removed both wheels and tank the chain, done front and rear brake pads and SS lines. It honestly is not a very difficult process once you do it once. However you will need a rear stand or means of raising the swing arm, and a torque wrench.
Start with removing the sprocket cover and finding the socket size that will fit the sprocket nut(14mm i think) Then if you have someone that can help have them sit on the bike and hold both brakes while the bike is in first gear and standing upright. Then use either a breaker bar or put some strength behind a socket tool to remove the nut (lefty lousy).
The next part will be to raise the rear of the bike with a swing arm stand or car jack or whatever you have to get the tire off the ground that you are comfortable with.
Now you will remove the rear brake caliper in order to avoid damage to the rotor. Then you will need to remove the rear wheel. Loosen up the rear axle nut.(right side- the left side is the axle rod) Now turn the chain adjusters in so you will have some play in the chain.
The next part is to slide the axle out of the rear tire. It helps to hold the tire up with your feet or an assistant so the axle can slide straight out and not be coming out at an angle. Once the axle is out slowly lower the tire to the ground and move it forward towards till it is against the back of the swing arm.
At this point the chain should have significant slack, and if you have the time you should take the chain off of the rear sprocket and clean the chain. If not you can leave it around the rear sprocket and turn the slack towards the front so you can remove the front sprocket.
Once you have slack up by the front sprocket it will not be difficult to just slide the sprocket off of its counter shaft.
Installing is basically the same steps, but in reverse. Remember that when you install the sprocket you will have to tighten the chain up, because it is smaller than stock. Also I suggest taking the time to clean and lube the chain while you are taking the time to work on everything.
Remember it is much easier to take the sprocket off in 1st gear as well as holding the brakes, because if you don't you might end up slipping the trasnmission like I did my first time when I wasn't holding the brakes. It took me about an hour or hour and a half the first time, and I was just winging it. I have done it 3 or 4 times now, and it only takes about 15 or 20 minutes including the chain tightening.
If you have any more questions or think I missed anything let me know.