i had a tb88 with a 18mm carb and had lots of torque i just upgraded to the racehead and it seems like the 88 with stock head is overall a better motor.... i have the same gearing between the to motors the only diff is 1 has a race head and a 20mm carb the other has a stock head with a 18mm... could it be my clutch slpping? im pretty sure its stock. should i go to a whole new hd clutch or just clutch springs? is 1 brand better then another?