Carb problems
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Joined: Mar 2010
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Carb problems
So here's the situation. I tried performi.ng the carb mod I saw posted on here #4 washer and changing the slow and fast jet. I wasn't able to get to the jets. I did shim the needle. I turned the air fuel screw all the way in to get a point of reference. I fired the bike up before turning the air/fuel screw back out and now I can't get the bike to stay running. Any thoughts, I'm kind of stumped
Supporter
Joined: Jan 2007
Posts: 15,787
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From: along the shore of Mishigami
Keep the jets. Turn the a/f screw 2 turns out as a reference after lightly seating it (turning it in). When starting the engine with the screw still in you aren't getting the fuel thru the idle circuit to keep the engine running. After the engine is warm turn the screw out 1/2 turn and that should be the max turns on it, find the sweet spot between 2 turns and 3 turns. Hope this helps you out.
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Joined: Jan 2007
Posts: 15,787
Likes: 5,610
From: along the shore of Mishigami
Check to make sure the vacuum hose is connected to the carb from the petcock. Turn the idle rpm adjustment screw about 1/8 of a turn. After the bike warms up turn the idle rpm adjustment to 1000+/- 50 rpms. Don't know why your plugs should foul out but check those anyways.
Ultimate HDF Member
Joined: Oct 2007
Posts: 7,562
Likes: 11
From: Palm Harbor fl.
couple thoughts... intake leak... pinched the diaphragm when reinstalling the cover.
Why can't you get to the jets? it's 4 screws on the bottom of the carb. Also shimming the needle is about the dumbest thing I have heard for carb tuning. the needle is designed to sit perfectly in the slide with the plastic part seating over it just right and the spring then above that. Shim the needle and the plastic piece no longer is seated at the bottom of the slide, this causes the spring to be compressed too much(like when you put more preload on a shock). and it can also bend to the side and bind a tad while the slide is under vacuum and moving up. This all slows the slide movement and can cause the slide to react incorrectly and it will start hunting on you. Don't shim the needle... buy an NOKK needle or the 88 sporty one for your carb. Also do not drill the hole in the slide to 1/8"!
Why can't you get to the jets? it's 4 screws on the bottom of the carb. Also shimming the needle is about the dumbest thing I have heard for carb tuning. the needle is designed to sit perfectly in the slide with the plastic part seating over it just right and the spring then above that. Shim the needle and the plastic piece no longer is seated at the bottom of the slide, this causes the spring to be compressed too much(like when you put more preload on a shock). and it can also bend to the side and bind a tad while the slide is under vacuum and moving up. This all slows the slide movement and can cause the slide to react incorrectly and it will start hunting on you. Don't shim the needle... buy an NOKK needle or the 88 sporty one for your carb. Also do not drill the hole in the slide to 1/8"!
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Intermediate
Joined: Apr 2010
Posts: 43
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From: Des Moines, IA
After checking for air leaks and messing with your idle and mix screws, might want to pull it back apart to check the diaphram. It stretches over time and could have been pinched or not seated properly when installing the cover back on it.
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Tourer
Joined: Dec 2009
Posts: 406
Likes: 13
From: Langley, BC. Canada
couple thoughts... intake leak... pinched the diaphragm when reinstalling the cover.
Why can't you get to the jets? it's 4 screws on the bottom of the carb. Also shimming the needle is about the dumbest thing I have heard for carb tuning. the needle is designed to sit perfectly in the slide with the plastic part seating over it just right and the spring then above that. Shim the needle and the plastic piece no longer is seated at the bottom of the slide, this causes the spring to be compressed too much(like when you put more preload on a shock). and it can also bend to the side and bind a tad while the slide is under vacuum and moving up. This all slows the slide movement and can cause the slide to react incorrectly and it will start hunting on you. Don't shim the needle... buy an NOKK needle or the 88 sporty one for your carb. Also do not drill the hole in the slide to 1/8"!
Why can't you get to the jets? it's 4 screws on the bottom of the carb. Also shimming the needle is about the dumbest thing I have heard for carb tuning. the needle is designed to sit perfectly in the slide with the plastic part seating over it just right and the spring then above that. Shim the needle and the plastic piece no longer is seated at the bottom of the slide, this causes the spring to be compressed too much(like when you put more preload on a shock). and it can also bend to the side and bind a tad while the slide is under vacuum and moving up. This all slows the slide movement and can cause the slide to react incorrectly and it will start hunting on you. Don't shim the needle... buy an NOKK needle or the 88 sporty one for your carb. Also do not drill the hole in the slide to 1/8"!
As for the comments about the spring pressure, we are talking about 1/32" here and it would take atomic measuring equipment to measure the effect on the spring. The plastic 'hat' (there to hold the needle down and the spring in the center of the slide) still sits flat and causes no issues with the slide or needle.
I think shimming the needle is one of the better suggestions here.
My 2001 Wide Glide is stock, except for K&N filter and V&H Straightshots and ran quite lean above the idle jet range, popping and coloring my pipes. My idle jet is fine as it adjusts within proper parameters.
I shimmed the needle on my bike and it made all the difference I needed. No more popping and the exhaust has a much meatier sound to it now, as well.
If you change the needle, you need to be very careful, because you then get into needle taper, which is a very complicated thing and you don't want to be doing that without full knowledge of what you are doing. Shimming the needle is the same as raising the clip on an adjustable needle and everything stays the same except the fuel flow will be very slightly richer from 1/8 throttle up when raised 1/32". Make sure the washer is about the same diameter as the 'hat' on the top of the needle. The thickness of the washer will dictate how much you are richening the fuel flow and 1/32" is about one clip position on an adjustable needle.
