CV carb problems
Thread Starter
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Road Warrior
Joined: Mar 2007
Posts: 1,959
Likes: 2
From: Florida
CV carb problems
I can't seem to get the float to work properly. It's such a simple thing, but I can't stop the overflow. Seems to work fine until I put it together and on the bike. Is there something I'm missing.
Also, a buddy gave me and old carb of his that he had "modified". Supposedly it was beefed up. The jets in mine are 42 and 175, and the ones in his carb are 45 and 176. That just doesn't seem like much of a difference to me. My bike is all stock, but the carb came off an 89 sporty. What should I have for best overall performance, assuming I get the gas to stay in the carb?
Also, a buddy gave me and old carb of his that he had "modified". Supposedly it was beefed up. The jets in mine are 42 and 175, and the ones in his carb are 45 and 176. That just doesn't seem like much of a difference to me. My bike is all stock, but the carb came off an 89 sporty. What should I have for best overall performance, assuming I get the gas to stay in the carb?
Road Master
Joined: Apr 2009
Posts: 1,123
Likes: 43
From: NJ
Common issue:
https://www.hdforums.com/forum/evo-c...e-problem.html
https://www.hdforums.com/forum/evo-c...verflow-2.html
If your bike runs ok other than the overflow, forget the jets and other carb, just fix what is broke.
Ds
https://www.hdforums.com/forum/evo-c...e-problem.html
https://www.hdforums.com/forum/evo-c...verflow-2.html
If your bike runs ok other than the overflow, forget the jets and other carb, just fix what is broke.
Ds
Grand HDF Member
Joined: May 2008
Posts: 4,326
Likes: 3,601
From: Picayune, Ms.
Turn the fuel tank petcock off when or just before shutdown, this will stop the over flow problem.
You can try taking the bike out and make sure you are getting full throttle response with no cut out during hard acceleration, try a roll on say from 60 to 80 as in passing on the highway and if the bike response normally I would leave the float level alone.
If it is running normally and you want to adjust, just adjust until the engine cuts out in the above test and then bring it back a bit. You will have to record the float needle adjustment each time. I use a vernier caliber and measure the width of the tang on the float arm. Usually something like .086in. width, but you will have to figure what and where you take your measurement.
FYI: What is commonly referred to as an overflow (and it is to keep from filling the engine up with fuel) also is the source for atmospheric pressure for the carb to function. That is why it doesn't leak when the engine is running.
If you do ultimately "fix" this problem let us know, you may be the first. Personally I think they added the fuel tank shutoff valve to fix this problem. :-)
You can try taking the bike out and make sure you are getting full throttle response with no cut out during hard acceleration, try a roll on say from 60 to 80 as in passing on the highway and if the bike response normally I would leave the float level alone.
If it is running normally and you want to adjust, just adjust until the engine cuts out in the above test and then bring it back a bit. You will have to record the float needle adjustment each time. I use a vernier caliber and measure the width of the tang on the float arm. Usually something like .086in. width, but you will have to figure what and where you take your measurement.
FYI: What is commonly referred to as an overflow (and it is to keep from filling the engine up with fuel) also is the source for atmospheric pressure for the carb to function. That is why it doesn't leak when the engine is running.
If you do ultimately "fix" this problem let us know, you may be the first. Personally I think they added the fuel tank shutoff valve to fix this problem. :-)
Seasoned HDF Member
Joined: May 2008
Posts: 21,104
Likes: 12,652
From: South Carolina
Turn the fuel tank petcock off when or just before shutdown, this will stop the over flow problem.
Clean the carb, you may need to replace the needle and seat. Make sure the little clip thing is installed correctly onto the needle.
Check the condition of the fuel line, make sure it is not deteriorating and getting debris in the needle and seat.
FYI: What is commonly referred to as an overflow (and it is to keep from filling the engine up with fuel) also is the source for atmospheric pressure for the carb to function. That is why it doesn't leak when the engine is running.
Advanced
Joined: Sep 2011
Posts: 50
Likes: 0
From: Irving, Texas
My carb runs a little rich also; can smell gas sometimes....but the bike runs great and leaks no gas......I am like Kabear, I shut the fuel off about 1/8th of a mile before i get home and let it idle till it runs out of gas.....and sometimes i just leave it on.....the carb does not need to have a fuel level in it..I get ready to crank her up, I can hear the pump come on, and I give it a couple twist on the throttle with choke and she fires right up every time...lol...Make a long story short; don't worry about it....Its a carbed Evo...one of the best engines Harley ever made...always will be....mine has 43k on it and runs like it just got off the showroom floor....never had a bolt touched on it, other than the fuel inlet valve replacement....its been to Cali twice and Sturgis twice by the previous owner with no issues but oil changes and adding gas....lol....
Thread Starter
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Road Warrior
Joined: Mar 2007
Posts: 1,959
Likes: 2
From: Florida
Thanks All. I was having problems leaking now and then. But for the most part, it's been good for a long time, I could leave the petcock open and no problems. So i bought a carb kit, and worked on it today, new gaskets and seals, and a new float needle. I put it back on the bike, hooked up the fuel line, turned on the gas, and right out onto the floor! It was getting dark, so I just shut the fuel off and called it a day. Tomorrow I'll try all the suggestions and get back with you!
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
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From: Coromandel Peninsula New Zealand
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Ultimate HDF Member
Joined: Aug 2012
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From: on the road
your float might of lost its floating ability or it could of picked up junk in the needle and seat allowing it not to seal.One of the things I have seen for years is degraded fuel line chunks sticking the needle.So make sure your fuel line from the filter is good to start
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Cruiser
Joined: Aug 2010
Posts: 181
Likes: 13
I had a friends bike with overflow problems (1990 dresser)and I opened the vent on the tank and placed a vent line from it to the same length as the overflow drain line as I suspect his cap was not releasing pressure at a low enough pressure which I suspect was causing carb to overflow. It is not overflowing now.
Last edited by tomfiii; Nov 26, 2012 at 01:17 PM.
Thread Starter
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Road Warrior
Joined: Mar 2007
Posts: 1,959
Likes: 2
From: Florida
Well, the float floats, the float needle seats, and it still overflows, even when everything is cold and no pressure. I refuse to believe I have to live this way! I've never had to turn my gas off so I wouldn't have puddles under the bike. Now I can't stop this thing. It runs good, and performance is better than when I started, BUT, I can't deal with this over flow. I can run it and drain the carb with the fuel shut off, turn on the flow, and about 1 minute later, it's draining out on the ground. I pulled the carb and kept it upright so not to drain the boal, and as soon as I cracked the screws holding the bowl, out it came. I'm stumped.