Another CV carb question...
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Joined: Oct 2009
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From: Hastings Nebraska
Another CV carb question...
Experimenting with different pipes, and tried to readjust the idle mixture. The screw didn't change anything, even all the way seated. So I took the air cleaner off and fired it up to see where it was getting it's fuel from. Couldn't see anything at idle, but just off idle I could see fuel coming up through the main jet. Is there anything besides a high float level that could cause this? I set the float by the book (on my drill press table at the correct angle), so I think it should be ok. It's got a 45 pilot jet, 180 main & the '88 Sportster needle.
The bike runs good, but I think it could be better.
Any ideas before I start tearing into it, so I know what to look for?
The bike runs good, but I think it could be better.
Any ideas before I start tearing into it, so I know what to look for?
Cruiser
Joined: May 2011
Posts: 205
Likes: 1
From: Always moving
Experimenting with different pipes, and tried to readjust the idle mixture. The screw didn't change anything, even all the way seated. So I took the air cleaner off and fired it up to see where it was getting it's fuel from. Couldn't see anything at idle, but just off idle I could see fuel coming up through the main jet. Is there anything besides a high float level that could cause this? I set the float by the book (on my drill press table at the correct angle), so I think it should be ok. It's got a 45 pilot jet, 180 main & the '88 Sportster needle.
The bike runs good, but I think it could be better.
Any ideas before I start tearing into it, so I know what to look for?
The bike runs good, but I think it could be better.
Any ideas before I start tearing into it, so I know what to look for?
Intermediate
Joined: Jan 2010
Posts: 32
Likes: 0
From: Philadelphia area
The Sportster needle definitely works to richen-up everything at idle, off idle and up to 3K rpm. It does get a little lean under load at 3K rpm, so beware of the dreaded ping. Many guys like to use the NOKK needle instead b/c it's rich enough down low and offers a richer transition @ 3k rpm under load to avoid the ping. Often, the "lightly seating then backing out" technique doesn't register hesitation when using the richer Sportster or the NOKK needles. Just seat it, then back out the idle mixture scew 2 and 1/4 turns, and you should be fine. Run it on a Dyno to get your AFR. Remember the MoCo produces them very lean, so "riching" AFR down to @ 13.5 :1 should give you a good compromise of decent power #'s and decent fuel mileage.
Cruiser
Joined: Nov 2008
Posts: 139
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From: Beaver, OK. (No mans land)
Turning air screw in all the way down should have an effect. I would start by looking at your enrichner and make sure it is seating check the cable at the elbow for separation. I wouldn't think a 45 be to rich
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Joined: Oct 2009
Posts: 54
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From: Hastings Nebraska
Cleaned out all the passages with carb cleaner & compressed air, checked enrichener and everything else I could think of. Put it back together and checked for vacuum leaks. Idle mixture screw still doesn't have any effect on idle. Runs and idles good.
Went for a 300 mile ride yesterday, and she purrs like a kitten, even 2-up going uphill.
Plugs are tan-colored, so it might be a tad rich.
Thanks for the info on the needles, Mr. Butler.
I think it's as close as it's gonna get without a good dyno tune. Thanks for the suggestions!
Went for a 300 mile ride yesterday, and she purrs like a kitten, even 2-up going uphill.
Plugs are tan-colored, so it might be a tad rich.
Thanks for the info on the needles, Mr. Butler.
I think it's as close as it's gonna get without a good dyno tune. Thanks for the suggestions!
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