Tight (New) Chain

[Den 08]

I have fitted a new 17tooth front sprocket used rear-46 the chain is an iwis 81 link there is hardly any up and down slack probably about 4-5mm so do I need to worry or will it slacken in use
I also notice a slight rattling when coming of the throttle I have checked sprocket alignment there is about .5mm difference
I have read that some front sprocket have been cut wrong how would or could I check this.
oh and do I really need a chain Guide
all comments welcome please.
Den

[RICSPEED]

do I really need a chain Guide

I don't but many recommend it

[Muppet]

Y don't ave to have a toilet seat but I prefer one

[jonashford]

iwis chains dont stretch easily,

[coaster]

I would think that the fact that you were able to get the sprockets on would indicate that there is some slack there, personally I would run with it, the slack will increase over time. As for the guide, personally I don't like the standard lower guide, the chain pulls tight under load anyway and the potential for breaking and getting jammed round a sprocket is a risk not worth taking in my book If you want to fit one, use one of the nylon after market ones.