I have a 98 Sportster 1200C, 4000 miles. I cut out the baffels & re-jetted. After about 15 min.or so of all kinds of riding it suddenly starts backfiring heavy out the exhaust & barely can keep it running,sometimes stalls out completely. If I pull over & wait 2-3 min. it will usually start & I can make it home on very light throttle. Fuel flow is good, checked carb. bowl & jets, all clean & OK. Any ideas out there????--runs great til it gets hot.