Backfiring
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6th Gear
Joined: Dec 2019
Posts: 12
Likes: 1
From: Jacksonville Florida
When you dyno test a carbureted bike, you remove the air cleaner and do a more air/less air test and see what happens. If they make more power, they were rich and if less, they were lean. Fuel standoff will go back into the carb, so having the air cleaner on would help if lean.
OP is saying the bike is super rich so going with that info. Feathering to achieve RPM makes me think lean.
If the bike is way too lean, it could be an issue without it, but it should also display other signs of being too lean (runs better warm, popping, etc.)
In the case of the car mentioned above, air cleaners are also flame arrestors.
From the OPs comment on using smoke to check intake, I am getting the impression the OP may be an auto tech, because checking intake leaks on HDs is not that complicated and certainly not worth the effort. I also am not 100% he is sure if it is rich or lean at this point.
OP is saying the bike is super rich so going with that info. Feathering to achieve RPM makes me think lean.
If the bike is way too lean, it could be an issue without it, but it should also display other signs of being too lean (runs better warm, popping, etc.)
In the case of the car mentioned above, air cleaners are also flame arrestors.
From the OPs comment on using smoke to check intake, I am getting the impression the OP may be an auto tech, because checking intake leaks on HDs is not that complicated and certainly not worth the effort. I also am not 100% he is sure if it is rich or lean at this point.
Thread Starter
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6th Gear
Joined: Dec 2019
Posts: 12
Likes: 1
From: Jacksonville Florida
the reason the air cleaner is off was to see where the dripping was coming from and turned out to be spitting fuel back out of the carb. I thought it was way to rich so leaving it off would lean it out some. Or so I thought.
When you dyno test a carbureted bike, you remove the air cleaner and do a more air/less air test and see what happens. If they make more power, they were rich and if less, they were lean. Fuel standoff will go back into the carb, so having the air cleaner on would help if lean.
OP is saying the bike is super rich so going with that info. Feathering to achieve RPM makes me think lean.
If the bike is way too lean, it could be an issue without it, but it should also display other signs of being too lean (runs better warm, popping, etc.)
In the case of the car mentioned above, air cleaners are also flame arrestors.
From the OPs comment on using smoke to check intake, I am getting the impression the OP may be an auto tech, because checking intake leaks on HDs is not that complicated and certainly not worth the effort. I also am not 100% he is sure if it is rich or lean at this point.
OP is saying the bike is super rich so going with that info. Feathering to achieve RPM makes me think lean.
If the bike is way too lean, it could be an issue without it, but it should also display other signs of being too lean (runs better warm, popping, etc.)
In the case of the car mentioned above, air cleaners are also flame arrestors.
From the OPs comment on using smoke to check intake, I am getting the impression the OP may be an auto tech, because checking intake leaks on HDs is not that complicated and certainly not worth the effort. I also am not 100% he is sure if it is rich or lean at this point.
you are correct in all things mentioned above. At this point I dont know if its rich or lean Iv never seen a carb spitting fuel out and bogging like its way to rich and then a few minutes later backfire out of the carb and blow it clean off the manifold like its super lean. I am more experienced with cars than bikes but everything uses the same principle to work. Or so I thought crazy Harley magic going on.
Stellar HDF Member
Joined: Mar 2006
Posts: 2,395
Likes: 153
From: Utah
On my son's bike it was spitting (I bought it used) and I went through the carb... had a dynojet kit in it and was running rich... ultimately replaced the coils to get a full spark and that was the main issue but the carb was fooled with by someone that though it would make the bike a hot rod... it is conventional wisdom that the first thing you do is fool with the jets if you touch anything on the bike's stock setup... e.g. pipes. Fooey... adjust the air fuel ratio by drilling out the epa plug... and keep the carb clean. If you want to drag race and not worry about replacing plugs to keep it running around town then you can "hop it up".
Thread Starter
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6th Gear
Joined: Dec 2019
Posts: 12
Likes: 1
From: Jacksonville Florida
Sorry it took so long getting back to you guys. Its fixed. There was an intake leak due to someone else incompetence putting the manifold bolts back in. Needless to say that I spend 3 hours retapping through bolt holes. After that I threw it back together and it ran pretty good but still had some to be desired. So new air intake and some tuning (bigger idle jet #45) and shes back to 100%. Thanks for the advice guys.
Road Captain
Joined: Apr 2018
Posts: 627
Likes: 324
From: Covington, VA
My 2005 XL883 with 20K miles and stock air filter and stock settings would always cough before the engine was completely warmed up to 200 degrees F. If I parked it for over 30 minutes in warm weather, it would cough until it reached 200 degrees. I checked the idle/air screw after I pulled out the factory plug to see if it was at the recommended 1 5/8 turns "out" and it was, so I left it alone. I pulled the Main Jet and Pilot Jet to see if they were clean and what their sizes were. The Pilot was 42 and the Main was 175 and both were clean. I replaced the 42 Pilot with a 45 Pilot and problem solved. For what it's worth, the crankcase is vented to the atmosphere, so the air intake is cold and dry instead of hot and oily.
Oh, I also checked the spark plugs for rich/lean problems and the plugs were both light tan with no carbon buildup at all, with 10K miles on them. So I didn't want to change the mixture. If the problem returns, my next step will be to add shims/washers to the slide needle.
Oh, I also checked the spark plugs for rich/lean problems and the plugs were both light tan with no carbon buildup at all, with 10K miles on them. So I didn't want to change the mixture. If the problem returns, my next step will be to add shims/washers to the slide needle.
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templeofdank
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