cause of carb hesitation, sputter fart?
#1
cause of carb hesitation, sputter fart?
Background info...2006 883, mostly stock. Last weekend I put on Vance & Hines shortshots, SE stage 1 intake that uses stock ham can and cleaned and re-jetted the carb with 44 pilot jet and 175 main jet and set also set mix screw to 2.5 turns out. The temps last weekend were mid 70's and the bike ran flawless all weekend! Not the slightest sign of a carb fart or any hesitation in any gear.
Fast forward to this weekend with the temps in the mid 50's. I took the bike out for a ride and did my usual ride the first few miles with choke out and gradually pushed it all the way in when it was warmed up. As soon as the choke was pushed all the way in the bike would hesitate, sputter and carb fart at about a steady 1/8-1/4 pretty regularly? What gives? Why would it all of a sudden start doing this after it ran perfectly last weekend? Should I up the pilot jet to a 45 or is does my bike really dislike the cokd weather that much? FYI the hesitation/sputter carb farts are worse in 2nd, 3rd and sometimes 4th gear and like I said at about 1/8-1/4 steady throttle or on a slight uphill. Thanks in advance and sorry for the long post.
Matt
Fast forward to this weekend with the temps in the mid 50's. I took the bike out for a ride and did my usual ride the first few miles with choke out and gradually pushed it all the way in when it was warmed up. As soon as the choke was pushed all the way in the bike would hesitate, sputter and carb fart at about a steady 1/8-1/4 pretty regularly? What gives? Why would it all of a sudden start doing this after it ran perfectly last weekend? Should I up the pilot jet to a 45 or is does my bike really dislike the cokd weather that much? FYI the hesitation/sputter carb farts are worse in 2nd, 3rd and sometimes 4th gear and like I said at about 1/8-1/4 steady throttle or on a slight uphill. Thanks in advance and sorry for the long post.
Matt
#2
#3
Did you take the rubber diaphram out of the top when you did the carb or did you do everthing with just the floatbowloff? Those rubber diaphrams are a bear to get seated right and if they aren't after a while a little pinch will become a tear or hole...
The pilot can make a difference. CV performeance makes a EZ adjustable Pilot screw kit that will allow you to fairly easily optimize your pilot while the bike is running.
The pilot can make a difference. CV performeance makes a EZ adjustable Pilot screw kit that will allow you to fairly easily optimize your pilot while the bike is running.
#7
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#8
I did not touch the top of the carb when I re-jetted it for fear of said diaphram issues.
I do plan on this week changing the plugs (and checking the color or the existing ones) and changine the oil as well as putting in a 45 pilot jet this week. I'll also check for obstructions in the jets but I highly doubt it since they are brand new and I usually run an ounce or so of PJ1 carb cleaner with every other tank of gas.
If the plugs are in fact fouled then why would my bike run like a scalded dog under hard accelerations then? It really ones stutters and hesitates under light load with the throttle and runs like a bat outta heck when I hit the throttle (it definitely seems like its searching hard for either more air or gas or both).
Thanks for suggestions and I'll report back with findings.
-Matt
I do plan on this week changing the plugs (and checking the color or the existing ones) and changine the oil as well as putting in a 45 pilot jet this week. I'll also check for obstructions in the jets but I highly doubt it since they are brand new and I usually run an ounce or so of PJ1 carb cleaner with every other tank of gas.
If the plugs are in fact fouled then why would my bike run like a scalded dog under hard accelerations then? It really ones stutters and hesitates under light load with the throttle and runs like a bat outta heck when I hit the throttle (it definitely seems like its searching hard for either more air or gas or both).
Thanks for suggestions and I'll report back with findings.
-Matt
#9
Cold weather = richer jetting. I would go to a 45 (period). Then for the sake of seasonal adjustment, buy an external mixture screw (the one with a big ****). This will allow you to adjust up to one pilot size in a matter of seconds. Easy stuff!
Oh, and I live at altitude 4500', which means I can run leaner jetting than most. I also have a 180 main with drilled out stock exhaust (differusers removed) and open air box (4 add'l - 1" holes drilled) with K&N filter on my wife's bike. My wife's 883 RUNS!!
Good Luck!
Oh, and I live at altitude 4500', which means I can run leaner jetting than most. I also have a 180 main with drilled out stock exhaust (differusers removed) and open air box (4 add'l - 1" holes drilled) with K&N filter on my wife's bike. My wife's 883 RUNS!!
Good Luck!
Last edited by Strick; 04-08-2010 at 09:15 PM.
#10
Great news! I did change the pilot jet to the 45 like you all suggested. I also put the mix screw to 2.25 turns out and it has fixed 99% of my carb farts hesitations so far. My only concern is that I have only run the bike this way in temps that have been in the 70's-90's. Before when it was hesitating and sputtering, the temps were in the low to mid 60's. I am going to contribute the sputtering and carb farts before to the 44 pilot jet for now until I can run it in its current 45 pilot jet state in some cooler temps. I'll keep everyone posted.
P.S. My new-to-me bike (2006 XL883 has approx. 8,000 miles on it as of last week. I have put about 1,000 miles on it since I got it in February. It was mostly stock when I got it. After about a month of riding (before I did my re-jet, pipes and AC) it started running terribly. It would idle ok but would hesitate majorly around 2-3K rpm. It would run ok when I really got on the throttle. I checked the codes and it really didnt show anything major. After experiencing the same major hesitating problems coming off idle after re-jetting with the pipes and AC, I replaced the crank position sensor on the front of the engine and this fixed the problem perfectly and it has run like a scalded dog since. Moral of the story if you think you are having a carb/fuel issue and are dealing with some stumbling and hesitating off idle you may have a bad sensor. It is worth checking rather than pulling your hair out adjusting the carb. The sensor was only $50 at the stealer and if it is not the cause of your problem, throw it in the tool box for when it does go bad later.
-Matt
P.S. My new-to-me bike (2006 XL883 has approx. 8,000 miles on it as of last week. I have put about 1,000 miles on it since I got it in February. It was mostly stock when I got it. After about a month of riding (before I did my re-jet, pipes and AC) it started running terribly. It would idle ok but would hesitate majorly around 2-3K rpm. It would run ok when I really got on the throttle. I checked the codes and it really didnt show anything major. After experiencing the same major hesitating problems coming off idle after re-jetting with the pipes and AC, I replaced the crank position sensor on the front of the engine and this fixed the problem perfectly and it has run like a scalded dog since. Moral of the story if you think you are having a carb/fuel issue and are dealing with some stumbling and hesitating off idle you may have a bad sensor. It is worth checking rather than pulling your hair out adjusting the carb. The sensor was only $50 at the stealer and if it is not the cause of your problem, throw it in the tool box for when it does go bad later.
-Matt