Chain only, or chain and sprockets?

ALWAYS replace the sprockets if fitting a new chain, it's a false economy not to.
If you want the maximum mileage from a chain, then apart from good maintenance, you should buy 2 front sprockets & one rear (steel) with a new chain. Run about half your expected mileage on the first front sprocket, then change to the second one.

The reason for this is that the rear sprocket is usually about 2.5 times the tooth count of the front one, thus the chain is always in contact with more rear sprocket teeth than the front & sees a chain to tooth interface 2.5 times less often than the front. It's the chain contacting & fitting into place that wears the teeth & chain rollers. So two front sprockets evens out the wear rate & stops a badly worn front sprocket accelerating the wear on the chain when it makes its tight turn around the front sprocket.

Also remeber a slightly loose chain will do less damage to itself & the sprockets than a slightly to tight one, but a correct adjusted chain will wear the least.

As to expected mileage, how you use the bike & the speeds you ride at will have a marked impact on the longevity of the components.

 

I don't want to start a war, but IMO that's just throwing money away. I've never changed sprockets that often and usually get around 25,000 miles out of a chain. It's your money and your bike, and this is just my opinion.

 

That's why I don't get too involved in the core of these discussions. People have their strong beliefs, and my evidence is entirely anecdotal.

My last VFR I did chain only the first time (25K-30K if I remember right, including a few track days) then changed to an RK and put another 25Kish on it (I stripped two of those speedo nuts, and wasn't in a hurry to fix them so mileage is inaccurate). Sprockets and chain then. Put another 30K on that one, though it is well past its prime even before I parked the bike for a few years. I really think I got an honest 25K+ out of each chain, even with old sprockets, just by maintaining the chain normally and keeping it adjusted -- which I really didn't have to do but once or twice at the beginning, then a little bit after 20K miles when it started to wear out.

Maintenance was simple. After a long ride or two weeks of commuting I'd lift the back wheel and clean the chain off with some WD40 and a rag. If it was wet out when I rode I'd do it as soon as I got home rather than wait.

Who knows? Maybe that second chain had 5K more in it. Maybe RK last longer than DID (I don't believe that, but maybe.) When it went bad it went pretty quickly, but the sprockets weren't awful. Just well used.

All that said, when I change this one I'll do the sprockets, too, even though they don't look bad now with 21K. It isn't cheap insurance, but very affordable if you plan on it. What's it cost? $75 more? I'll just amortize it at $25 a year -- skip eating out for lunch two days per year and tuck that in a savings account for bike maintenance or something.

 

Decided to have a look at the countershaft. Any new/further advice?

 

I have read on here and VFRD where 520 have been run with no problems. I run and know a bunch of guys also with 1k track bikes that run 520 set ups and they are not babied. 180 hp, geared track bikes are great testing grounds. Less rotational mass is a good thing.

 

Run those sprockets and replace everything with next chain.....