I picked up my 81 cm 400 last year and the previous owner said it was having some acceleration issues and he only got it up to about 45-50 so once I bought it I took her out and got the same result till I figured to shift at a higher RPM and I got her to go about 65-70 but I have to run the RPMs pretty high to get there. I did some research and read the top speed is about 95 mph. When I first accelerate the I have to kinda hammer on the throttle so she doesn´t stall, I don´t know what could be causing these issues.