chain life/adjustment/replacement

Have serviced the bike and have now convinced myself that it needs a new chain
I know that there are loads of variables but how many miles would an OE chain & sprocket last approx?
Is there an easy way to check the front/rear wheel alinement, marks on swingarm are never accurate supposedly!
Have read about bits of string or straight edges and tyre width calculations. Have you tried to find a true straight edge?
Is it reasonably straightforward to replace both the sprockets and chain yourself?
Read the recent post £99 fitted sounds a great deal but miles from London
Chris

As to chain life,,depends on how its been looked after from new,ie checked and adjusted as required,how often its been cleaned/oiled etc,

the chain on my zx6r at 17500 miles was original but due a new one when i sold it,and the rentabike i borrow at the moment has 20700 miles on and still on its original set,but does need new one

if it looks ok and no tight spots developing and the sprockets not like vampire teeth then i would not go to the expense just for the sake of it.

If you have 90-115 to do it then for piece of mind the n go for it,and most decent bike places will do it for about that ????

theres FWR in London that does c&s fitted for that

pete

Pete thanks for info.
Bike has done 29000 on original so probably due replacement
just been in yamaha dealer OE £150/£220 fitted pattern £20 less
Chris