Besides the lrg chainring for the jackshaft and the chainring for the drive chain are you running a front derailleur with other chainrings? Very curious, I too have the SBP shift kit, but running 8 gears in the back and only the one on the front.
Tnx
Pete
This is the same gear set up I've used on my 3rd jackshaft build, Red. You can see pics of Red in my other albums. Red has gone over 600 miles. Haft that at night and 1/4 of it on steep dirt roads. see "Red over Mt. Lemon" on youtube