Well, after doing the spin test, the diff is a 2.5 to 1. That's good, but still not great. The chain drive is 1.5 to 1 and the 1st gear ratio is 2.77 to one. It all works out to about 10.xx to 1 final drive for first gear. With a normal engine that might be ok, but with the 1300 rpm idle for the GSXR it would idle at about 10 mph in first and top out at around 70mph (still in first).
I can replace the 17 tooth gear on the tranny with a 13 and that would make the 1.5 turn into about 2.0 to 1. Better, but still not great.
I might be able to find a bigger back gear for the chain, but I can only go so big without hitting the half shafts. I'm hoping to replace the 26 tooth with a 30 or larger tooth sprocket.
13/30 = 2.31 chain ratio (vs 1.5)
2.31*2.47*2.77 = 15.77
Those 2 changes would bring the final drive to 15.77 to 1. And allow a 5 mph crawl at 1100 rpm. Top speed in 1st would still be over 50 mph.
I can see why people run direct with large rear sprockets. I may be changing some clutches before I finally get this figured out.
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