[jebersole]

First, I admire you for embarking on a S.America motorcycle trip where, based on your chain questions, I'm assuming you are pretty new to riding.

Maybe you've just never had a bike with a chain on it...

Anyway, the chain spec (which is a measurement of length), and chain tightness or slack, which is adjusted by loosening the back axle and moving the back wheel either forward or backward using the hex adjusters at the back of the swingarm, are two completely different things.

There is plenty of info on this site for both. Now that you know the difference, do some more searches. I guarantee you will find a wealth of information.

--jason

 

[Sprocket]

1. It's 20 pitches, not 20 pins. Twenty pitches includes 21 pins. The difference in length over 20 pitches between a new chain and one that it out of spec is only about 2mm, so it's not easy to measure with accuracy. If your bike has less than 15,000 miles and you've maintained the chain reasonably well, it's not likely that it's out of spec. I wouldn't worry about trying measure it.

3. Put the transmission in neutral. You can measure the top or the bottom of the chain. No difference. Chains sometimes don't wear evenly at all points, so the distance between the same number of pins at one segment of the chain may be different than the distance between the same number of pins elsewhere along the chain. This means that there will be slightly more or less slack as different segments are positioned between the front and year sprockets (not cogs!). This is what people mean when they advise adjusting chain slack at the tightest point. You rotate the wheel a bit, check the slack, rotate the wheel a bit more, check the slack, repeat until you've found the minimum slack. Keep the rear wheel in that position when you're setting the slack to spec. Having the bike in neutral will minimize the effect of these slight differences in segment lengths.

7. It's recommended to replace both sprockets and the chain at the same time to maximized the life of all three components, but you'll find lots of testimonials from people who don't replace lightly worn sprockets and still get good life from a replacement chain.

4 and 9. One inch is the middle of the spec, but a lot of people run more slack than that. I doubt that 1.5" is dangerous.

8. I hope you're kidding. Space must really be tight.

10. More noise, sometimes a bit of jerky-ness at low speed.

 

[greywolf]

1. It's 20 pitches, not 20 pins. Twenty pitches includes 21 pins.

 

[honest bob]

What the other guys said +

1. They ask you to tighten (draw the back sprocket further back) it so that the links are under tension so that you are measuring them at their stretched out length (will be longer than relaxed length)

2. You are correct.

3. You check it half way between the sprocket centers where it will travel the most up & down.

5. No it means your chain is too short, not enough links. However, when you turn the adjusters to shorten the distance between sprockets, (loosen the chain) you must push the rear wheel forward, the adjusters won't move it by them selves.