Motorcycle Repair: suzuki maurader, suzuki marauder vz800, 2001 suzuki marauder

Question
Hi I have 2001 Suzuki Marauder vz800 will begin to stutter at 75mph and doesnt pick up any speed after 80mph. i have taken for a tune up and changed air filter. the problem started after i taken it to the shop and now the mechanic doesnt know what causes the problem if you have any advice or know of similar problem please let me know about it and what could be the problem

Answer
Pull the sparkplugs and look at them. If the front plug looks a little darker it may be running to rich.The theory is to rum a bigger main jet in the rear cylinder to get more fuel in to cool it because it runs hotter. The jets can be switch accidentally. The front main stock size is a #90 and the rear should be #100 also make sure the shop syncronized the carbs after ccleaning and adjusting. Sometimes the linkage sticks or has a weird wear pattern and messing with them screws the runability up.