adjusting chain

hello all!

i got myself a new 2003 triumph sprint st this spring, and i am
thinking it may be time to adjust the chain. the manual gives good
instructions on accomplishing this, but i cannot figure out one part.
it says that i should find the 'tight' spot in the chain and take my
measurements there. how do i find the tight spot? i know the rear
cog is slightly eliptical and all, but not enough that i can easily
see a 'tight' spot when turning the wheel.

also, is there some kind of gauge or tool to help in measuring chain
play?

thanx all,

matt n

 

The variation in chain slack is not due to either sprocket being
out of round- the links of the chain don't all wear at the same
rate. When the chain is near the end of life, this uneven wear
can result in noticeable variation in the amount of slack as you
turn the wheel. On a newer chain there shouldn't be much wear,
and even less difference in wear between any two links, so there
should be little if any change in slack as you turn the wheel.

A ruler, hold it up next to the chain, resting the end on the
swingarm or some fixed point, and look at the excursion of the
chain as you pull it up and down. The total amount of movement
of the chain (usually 1/2 way between the sprockets) is the
measurement of interest.

 

Hi Matt ;->
As the other folks have said, the chain will be tighter when sitting on
the bike, but What the manual is referring to, (like Mark said, is that
the chain wears unevenly, and the sprockets are not perfectly round) is
the place during the rotation of the wheel where the chain is the
tightest. If you have a center stand, put it in neutral, and rotate the
back wheel, you'll notice that at some points in the revolution of the
chain, it will sag a little, and other points it will be tighter. Using
a ruler, or better yet, a combination of your finger pressure on the
lower part of the chain (pushing towards the ground) and a ruler or keen
eye, rotate until you find the tightest spot. Adjust from that spot, and
you got it!
Good Luck with Your Trump!
Paul

 

A contibuting factor might be the chordal action, where the chain contacts
the sprockets, especially the front one. The chain would become slightly
tighter as it climbs onto the sprocket.

D.