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Hoping somebody has some experience with this so that I can stop pulling my hair out!!
OK, I bought an 87 Interstate that had sat for 7 years. Initially it would not run due to that wonderfull stuff that old fuel turns in to. After the 1st round of carb cleaning it ran fairly well, but had a 'muffled' sounding backfire that you could tell was coming up the intakes. WhenI balanced the carbs, only cyclinder 2 intake vacuum would drop off during the backfire. The bike idles well once warm and the backfiring seems prevalent fromabout 1250 to 3000 rpms, after that it smooths out. On the road, you can tell the engine is holding back during this rpm range. The second round of carb cleaning really didn't find much, but they were soaked in cleaner and blown out with high pressure air again. Engine still has the backfire problem. I will be checking cyclinder compression this week after I borrow a gauge. During idle, I have checked the exhaust pipe temps at the headers and they all are within a few degrees of each other, so they all are firing well at idle at least.I still have to put newspark plugs in it, that will be done this week.
ANY help, questions, answers, or general chit-chat is always appreciated.
THANKS,...Chris.
Hoping somebody has some experience with this so that I can stop pulling my hair out!!
OK, I bought an 87 Interstate that had sat for 7 years. Initially it would not run due to that wonderfull stuff that old fuel turns in to. After the 1st round of carb cleaning it ran fairly well, but had a 'muffled' sounding backfire that you could tell was coming up the intakes. WhenI balanced the carbs, only cyclinder 2 intake vacuum would drop off during the backfire. The bike idles well once warm and the backfiring seems prevalent fromabout 1250 to 3000 rpms, after that it smooths out. On the road, you can tell the engine is holding back during this rpm range. The second round of carb cleaning really didn't find much, but they were soaked in cleaner and blown out with high pressure air again. Engine still has the backfire problem. I will be checking cyclinder compression this week after I borrow a gauge. During idle, I have checked the exhaust pipe temps at the headers and they all are within a few degrees of each other, so they all are firing well at idle at least.I still have to put newspark plugs in it, that will be done this week.
ANY help, questions, answers, or general chit-chat is always appreciated.
THANKS,...Chris.