H
harmon44e
Guest
I'm working on a bike (1980 GS850) for a neighbor that has a sparatic popping sound from the carbs. The story of the bike goes as follows: he took it to a shop becuase it wouldn't idle, they said the problem was the intake boots, then said the packing was bad in his mufflers. Instead of repacking the mufflers they rejetted his carbs and put on aftermarket air filters. $800 later the idle problem is fixed but now has a popping sound.
The bike runs fairly good, a little sluggish outside the powerband but smooth and no problems in higher rpm range. The popping can't be duplicated but happens most often at cracked throttle (cruising and decel) and no specifc RPM, and in all gears and is sparitic between carbs. It will also do it at idle and doesn't seam to care if its cold or warm. I have a 550 and campaired to mine his takes a long time to warm up and needs to be chocked. We are in the 200-300 sea level range.
I took the carbs off and cleaned them and recorded the folling jets sizes (I'm usure of what the correct jets names are but hope someone can tell by the #'s) 180/40/146 (only 3 had 146 one was a 136
). The idle screws are all at different levels with one even being completely closed. He does not have the orignal air box and I have been unable to find out what the orignal jet sizes should be (in the event he goes back to stock).
The current air filters are K&N RC-2382 and the paper work says to increase jet size by 10% but like I said I have no idea what stock is. I'm under the assumtion that it didn't have the probelm before the "rejetting" and it does after then it must be a carb issue. I'm very mech inclined but bikes are still new to me and I need help in knowing which way to go. Ideally the cheapest way possible. He paid $100 for the filters and in my opinion I think the best option is to get the carbs matched to it. So I'm all ears (well in this case eyes) for advise.
The bike runs fairly good, a little sluggish outside the powerband but smooth and no problems in higher rpm range. The popping can't be duplicated but happens most often at cracked throttle (cruising and decel) and no specifc RPM, and in all gears and is sparitic between carbs. It will also do it at idle and doesn't seam to care if its cold or warm. I have a 550 and campaired to mine his takes a long time to warm up and needs to be chocked. We are in the 200-300 sea level range.
I took the carbs off and cleaned them and recorded the folling jets sizes (I'm usure of what the correct jets names are but hope someone can tell by the #'s) 180/40/146 (only 3 had 146 one was a 136
). The idle screws are all at different levels with one even being completely closed. He does not have the orignal air box and I have been unable to find out what the orignal jet sizes should be (in the event he goes back to stock).The current air filters are K&N RC-2382 and the paper work says to increase jet size by 10% but like I said I have no idea what stock is. I'm under the assumtion that it didn't have the probelm before the "rejetting" and it does after then it must be a carb issue. I'm very mech inclined but bikes are still new to me and I need help in knowing which way to go. Ideally the cheapest way possible. He paid $100 for the filters and in my opinion I think the best option is to get the carbs matched to it. So I'm all ears (well in this case eyes) for advise.
