Test the tension of your current chain in several places - they can wear unevenly and you may well find that where it is correct or loose in one spot it can be drum tight in another - this is not good for the sprockets and drive side bearings.
It sounds like you're going to need a new chain and probably sprockets. Buy a decent quality set with an 'O' ring chain- Thumpers really give the chain hell and a cheap chain will be knackered very quickly. Buy and fit a chain oiler -
LOOBMAN is cheap and efficient ( if a little fiddley to fit) and it will make a massive difference to the life of your chain and sprockets.
Try
www.wemoto.com for spares they're good and reasonably priced.
The chain is continuous so you'll need either a proper motorcycle chain breaker to remove it or grind the heads of a couple of the chain rivits with and angle grinder. You
should really get the new chain re-rivited to join it, but to be honest the XBR is pretty low powered - in spite of Honda's 44BHP claim I've never known a standard one dyno'd at more than 32-34 bhp at the back wheel - so I would have thought a chain split link would be amply strong enough ( a lot of older, bigger bikes used them no problems) but thats your choice.
Oh if you fit the Loobman and 'O' ring chain make sure you don't use old engine oil to lube it ( you can with cheap non 'O' rings chains) as it will bugger up the seals - I use cheap(ish) supermarket own brand 10/40 ( or whatever else is cheap).
