I recently bought a biturbo pipe, 15mm Bing carb, performance air filter, new clutch and throttle cables; cleaned all the carbon of the head/piston, cleaned points, changed transmission fluid (type F), de-rusted/kreened the gas tank, replaced the petcock, new fuel filter and checked the timing on my 78' Puch MKII. It was running great, but now it is bogging down at low-midrange to midrange. If I barley lay on the gas it quits bogging, but barley accelerates. I barley advanced the timing, but am now running on a higher octane gasoline. Just did a plug chop and it comes out coffee brown. Is this a jetting problem (The new carb came with a *82)? Or, could I possibly need to adjust the clutch cable, since I put in a new one, or adjust the needle inside the carb that regulates midrange fuel output?