Gear changes
 

I see a lot of you have gone to a 13/45 arrangement. Is that because you don't have to lengthen your chain like you would if you left the counter shaft stock and enlarged the rear for a similar ratio?

Correct and correct!

There is adjustment to spare to take up chain slack going from a 14 to 13 tooth front sprocket. To get the same reduction changing rear sprocket, you would have lengthen the chain and you may encounter problems in the rear chain guide area as well.

Some people shy away from the smaller front sprocket option claiming increased wear due to tighter radius the chain must go around. Unless you go to a 12T I personally believer the "wear factor" is insignificant. This is a hefty chain given the modest output of these engines.

My personal opinion on stock gearing:

1st ... too high for slow speed slogging in the dirt, little too low for street
2nd ... big jump from 1st, too high for dirt, OK for street
2nd -5th ... OK for either, nicely spaced ratios
6th ... very close to 5th gear, OK for higher speed cruising on street, too high for dirt unless hard packed & flat

Going to a 13T front:

1st ... Much better for dirt, too low for street (start out in 2nd)
2nd ... Much better for dirt, good "1st gear" for street
2nd - 5th gears ... OK for either
6th ... more usable for both street and dirt.

I think the 13T improves off-road capabilities with minimal impact on street use.

108 links needed for 13/45 (stock is 106 links) but gives the option of going 14/45 without lengthening the chain., 108 links works for 14/45 too.:D