I recently replaced the sprockets and chain on my 98 cbr600 f3. I kept the modification of the last owner of -1/+2. Since then I have noticed a sound like gears under load. This hum starts at about 30 mph and is gets louder as speed increases. Neutral throttle position also makes it more prominent.It is related to mph not engine rpm.
My first thought was it takes time for the sprockets and chain to wear into each other a little but its been 200 mi. now. Anyone have any ideas? The chain has about an inch of slack half way between the sprockets. I did see Juliets' post elsewhere suggesting 1 1/4 inch. So I will loosen it up a bit. Any help is welcomed.
Thanks
mikey

 

What you also have to consider when you do your just adjustment (apart from making sure you adjust it from the chains tightest section) Is your weight when you get on the bike. Not suggesting your a lard **** or anything, but when you sit on your bike, the compression of the suspension also takes up some of the chain slack, the heavier you are the tighter the chain. Chains do take a bit of time to 'wear in', but that usually takes the form of them stretching quickly for the 1st hundred or say clicks.
Also make sure that you have aligned your rear wheel correctly, the line up marks on the rear wheel are notoriously inaccurate, A simple way to do it, is to turn each adjustment bolt the same amount of turns & that will be a good indicator to their accuracy. (I would also increase the slack to what Jules suggested

 

I'll agree that perhaps the sprockets aren't aligned, thus the chain may be rubbing against one side of the teeth. One thing I've noticed is that you may get the chain adjusted perfectly where you want it (centered), but as soon as you tighten that axle bolt, it gets all ****-eyed again, so you have to compensate for that slight shift. Here’s a decent thread on one way to achieve chain alignment: LINK.

 

Too tight

Oh yeah sounds like the same thing I did last week..........chain too tight back it off another turn and align the sprockets ............I was in a hurry get out riding when I tightened mine up too much one day...easy to have happen

 

Thanks for your help on this one. I plan on getting to it this weekend.
mikey