I have a 1994 and a 1999 Kodiak 400 4x4. Both are hard starting (cold blooded) and backfire frequently when revving the engine, also they both will not idle until they are completely hot. Is there a fix out there for these mukuni carbs? I just bought the 1999 this fall from a dealer. I thought yamaha would have come up with something better in 5 years but I guess not. Any ideas?