i have a 97 xc 440 it startts fine but when you give it gas its boggy and backfires through carbs. i know its running rich but it was running fine 5 mins before it starting acting up. I checked the compression both are at 127 lbs. Main jets are 200 and choke cables are readjusted. It kinda sounds like a short but i can not find it. About what jets should i be running. Any input would be greatly appreciated and thanked for.