Changing front rear sprocket and chain what size is the socket for the front sprocket for my 1987 FZR 1000

Take off wheel...remove cush drive on sprocket side...prise the oil seal out on the brake side and you'll see a circlip...remove this and drift bearings out. Drift new ones in with a socket or bit of tubing that is the same size as the bearing outer so as not to damage the bearings...re-fit circlip.

To replace the front sprocket follow the chain to the cover on the left side and remove it, loosen the chain tensioners on the rear axle, slide rear wheel all the way forward and remove chain. Then remove the bolt in the center of the front sprocket, change sprocket and reverse process for assembly. That is the process but if you are going to change the front sprocket you should change both sprockets and chain, as the chain stretches and will cause premature wear of the new sprockets. Complete sets can be found on Ebay for little money, maybe they are not the best but as long as you do not abuse them they will do until you get the money for a good set.

1st. - NEVER change sprockets without changing the chain..and vice-versa!! - they need to be replaces as a set...they wear our almost equally.. ie - a worn out chain will wear out new sprockets... A new chain will get stretched out by worn sprockets real quick!
Its east to tell what you have...

• OEM sprocket size: 16/43 - 2.68 ratio.

1. Count the teeth on your front sprocket.
2. Count the teeth on your rear sprocket.
Compare yours with stock(OEM)..
Now, if your sprockets match the stock sizes - count the number of links in your chain...(count the inner links).
If the sprockets are different sizes you adjust the chain by that number using inner links. - Usually people go smaller on the front or a larger rear.. this increases the ratio to give a quicker take-off - (more acceleration).
15/43 = 2.86
15/44 = 2.93
15/45 = 3.00
15/46 = 3.06
..when you get a new chain... better to get one a couple links too long than one link too short!!
Your local dealer will be more than helpful!!

Must be no more than 1 and 1/2 inches overall. ( from fully up to fully down) measured in the middle of the lower chain run.

A bad bearing is a possibility alright. Also check the chain. is it free or does it want to kink up? Is it rubbing anywhere on the side case or side case cover? Remover the cover to check. Has mud built up around the sprocket shaft?

The original chain was DID50V4 , 110 links using 17 tooth sprocket on the front and a 42 tooth on the rear, remember to check the sprockets are the correct size before ordering a new chain

The first step is to find the tightest part of the chain. Unless it's a brand new chain it will have a tight spot somewhere on it. It's easiest to do this with the bike on a race stand if you have it. Rotate the wheel and observe the lower part of the chain and watch it lift up when you hit tight spots. The spot where the chain lifts highest is the tightest part of the chain. Once you have found this spot, grab the chain on the low side under the swingarm and move it up and down. It should move up and down around 30-35mm or so, or an inch and a bit if you're an imperialist :) If the chain moves more or less than this then it needs to be adjusted.

To adjust the chain, you need to loosen the axle first. Don't take the nut off but it has to be loose enough to undo by hand. Using 2 spanners, unlock the lock nuts on the end of the swingarm and wind the nut in or out until you get the correct amount of chain slack. always do the sprocket side (left side) first, then repeat the same on the other side. Check the chain adjuster marks to make sure that the adjusters are equal on both sides, this will make sure your rear wheel is aligned properly.

Once you have adjusted the chain, tighten the rear axle and check again. The chain slack will change slightly after you tighten the axle, it might go tighter, it might go looser. Depends on the bike. But the chain slack must be correct with the axle tightened. A bit of practise here and you will be able to guess the correct amount before tightening the rear axle.

Once you have the slack set correctly and the axle is tight, make sure to tighten the adjusters. Tighten the front nut first against the swingarm plate so it can't move. Do it tight but not crazy tight. Then holding the first nut so it can't move tighten the locknut against the first nut. Repeat this on both sides.

If you are not quite sure if the chain is right, always err on the side of making it too loose rather than too tight. Running your chain too tight can destroy your output shaft bearing. It's only about $30 or so for a new one but your engine needs to be completely stripped down to replace it, it's not a fun job. I have seen a lot of FZs and FZRs have this problem because people ran chains too tight. If your chain really is too loose then it will start making your gear changes harder to do, that's the sign you need to tighten it.

If you lean the bike over to the right , no oil will come out while you change the seal. If any did come out it would be quite slow. This seal and bearing will have a pressurized oil feed

check the cam chain tensioners.