36.1 with proma pipe, stock cylinder, stock belt and SHA. The proma is not a top end pipe but acceleration is fantastic with it on the SR. I think you have to kit it to get it above 40 mph. Those tiny tires are working against top end big time. They work for you when it comes to take off though. I think we are at ~31 grams in variator.
What's the stock tire size 8 x 2.75"? I got an 8 x 3.5" on the rear. Doesn't sound like much but it dwarfs the stock tire. You don't want to be doing low to mid 40s on the stock tires anyway. A DR kit should spin that big ass rear real nice. Get a better carb than stock as well. We run the stock belt flipped inside out. And I think I shaved a couple mm off the boss as well. We did the gy6 clutch and a yellow contra.
Don't let that motorscooterguide.net site fool you with some BS about how this thing did 35 stock. Maybe 30.
I see you are working on the center stand dilemma as well. (edited)