CV Carb Tuning Questions
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Intermediate
Joined: Apr 2024
Posts: 48
Likes: 21
From: Western Washington
Yes, good call. I read that and made sure to not overtighten. I also made sure to replace the old o-ring in the "well" for the mixture screw, being sure to keep the washer and o-ring in order on the end.
Tourer
Joined: Feb 2009
Posts: 298
Likes: 103
From: King Island, Tasmania
At the risk of telling you how to suck eggs if you pull it apart to clean it again give it a real good go with cleaner through the idle mixture port and transfer ports, from the bowl end as well, I'd take the screw out again and go in through there to, you have probably done this already, thought I'd mention it just in case.
HDF Community Team
Joined: Dec 2005
Posts: 5,394
Likes: 2,596
From: NC USA
At the risk of telling you how to suck eggs if you pull it apart to clean it again give it a real good go with cleaner through the idle mixture port and transfer ports, from the bowl end as well, I'd take the screw out again and go in through there to, you have probably done this already, thought I'd mention it just in case.
Seat the idle mix. With the slide and the low jets removed, hold or better prop the throttle plate open. I'm not a safety freak but watch your eyes on the next step.
With your left thump over the low jet hole and fore finger holding the top, sprat into the low air port until you can see 4, count them 4 geysers of fluid coming from the low circuit ports.( Low air jet is the one on the left looking from the air cleaner side)
Each one of those holes will flow more than a 65 jet but if even one of them is plugged or deficient, the low circuit will not operate correctly.
If the mix screw o-ring is damaged or missing, the idle circuit will not operate correctly.
Thread Starter
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Intermediate
Joined: Apr 2024
Posts: 48
Likes: 21
From: Western Washington
Ok, so I followed the instructions for clearing/cleaning out the carb. I put it all back together again, installed it, and turned the fuel switch on....immediately started leaking out the fuel overflow from the bowl. I turned the fuel off and walked away. I didn't even try to start it.
Of note, I was going to replace the slide/diaphragm but noticed the diaphragm was torn when I opened the box, so I'll be sending that back to CV Performance for a new one. So the existing one stayed.
I didnt replace the manifold to head gaskets...Ill do that when I take the carb off again. I was going to run it with the old gaskets first and see if it ran well or not, then change them out if the same problem persisted....
Throughout this process, I didnt adjust the float, but I did replace the float needle and cleaned the float off as it had some gunk on it. Maybe I somehow bent the little metal tab for the float needle when cleaning it?
Do I take it all apart again? Or do I just focus on the bowl/float? Also, I've never adjusted the float....so I'm very open to suggestions on this.
I really appreciate all the information so far. Thank you.
Of note, I was going to replace the slide/diaphragm but noticed the diaphragm was torn when I opened the box, so I'll be sending that back to CV Performance for a new one. So the existing one stayed.
I didnt replace the manifold to head gaskets...Ill do that when I take the carb off again. I was going to run it with the old gaskets first and see if it ran well or not, then change them out if the same problem persisted....
Throughout this process, I didnt adjust the float, but I did replace the float needle and cleaned the float off as it had some gunk on it. Maybe I somehow bent the little metal tab for the float needle when cleaning it?
Do I take it all apart again? Or do I just focus on the bowl/float? Also, I've never adjusted the float....so I'm very open to suggestions on this.
I really appreciate all the information so far. Thank you.
Tourer
Joined: Feb 2009
Posts: 298
Likes: 103
From: King Island, Tasmania
Your float level may or may not be the culprit but you are going in there again regardless, take the float out and check the valve seat, maybe it needs a good clean, a cotton bud soaked in cleaner and twirled on the seat, the rubber on the end of a pencil I've heard of being used, even a fine paste on a cotton bud, there is probably a tool for the task, I dunno, check the needle tip and if all is well and cleaned out put it back together and set the float.
You should Google it for a video or two but quick explanation, you want to tilt the carb to 15° with the float trying to close, you want the seam of the float parallel to the carby bottom surface but making sure the little plunger in the needle is not compressed, the 15° should do it, there is a measurement tolerance for how far the float is above the mating surface if you want to go there but seam parallel has put me in the tolerance in the past.
Do watch a vid or two, seeing is better that reading, the procedure is in the service manual as well if that is easier to understand than my jibber.
You should Google it for a video or two but quick explanation, you want to tilt the carb to 15° with the float trying to close, you want the seam of the float parallel to the carby bottom surface but making sure the little plunger in the needle is not compressed, the 15° should do it, there is a measurement tolerance for how far the float is above the mating surface if you want to go there but seam parallel has put me in the tolerance in the past.
Do watch a vid or two, seeing is better that reading, the procedure is in the service manual as well if that is easier to understand than my jibber.
Thread Starter
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Intermediate
Joined: Apr 2024
Posts: 48
Likes: 21
From: Western Washington
Your float level may or may not be the culprit but you are going in there again regardless, take the float out and check the valve seat, maybe it needs a good clean, a cotton bud soaked in cleaner and twirled on the seat, the rubber on the end of a pencil I've heard of being used, even a fine paste on a cotton bud, there is probably a tool for the task, I dunno, check the needle tip and if all is well and cleaned out put it back together and set the float.
You should Google it for a video or two but quick explanation, you want to tilt the carb to 15° with the float trying to close, you want the seam of the float parallel to the carby bottom surface but making sure the little plunger in the needle is not compressed, the 15° should do it, there is a measurement tolerance for how far the float is above the mating surface if you want to go there but seam parallel has put me in the tolerance in the past.
Do watch a vid or two, seeing is better that reading, the procedure is in the service manual as well if that is easier to understand than my jibber.
You should Google it for a video or two but quick explanation, you want to tilt the carb to 15° with the float trying to close, you want the seam of the float parallel to the carby bottom surface but making sure the little plunger in the needle is not compressed, the 15° should do it, there is a measurement tolerance for how far the float is above the mating surface if you want to go there but seam parallel has put me in the tolerance in the past.
Do watch a vid or two, seeing is better that reading, the procedure is in the service manual as well if that is easier to understand than my jibber.
Thread Starter
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Intermediate
Joined: Apr 2024
Posts: 48
Likes: 21
From: Western Washington
Update- She's back to running great! I basically re-cleaned everything again. I set the float bowl using an angle gauge and measuring the distance within tolerance/spec, basically the line on the float is parallel to the edge of the machined face/body of the carb.
I'm guessing there was still some junk inside the veins of the carb causing problems and when I squirted brake clean through it cleared out.
No more backfiring/popping from the exhaust and no more hiccups from the carburetor.
As annoying it was to take it apart several times, at least I learned from all the advice given and actually going through the process of it all.
I also changed the main jet from a 165 to a 170. I didnt really notice anything from this. I dont think I needed to do this. I checked under the push rod tubes and noticed the push rods are solid after I installed the bigger jet. I was told by a local Harley tech that the push rod tubes on the bike were aftermarket leading him to believe the original push rods had been cut and adjustable push rods installed and cam was installed by how it sounds...now I'm thinking it just has the stock cam.....who knows until later when I plan on opening up the top end and then I will pull the cam cover and verify. Im just going to ride it for the time being and change the main jet back to the 165.
I appreciate everyone's input!
I'm guessing there was still some junk inside the veins of the carb causing problems and when I squirted brake clean through it cleared out.
No more backfiring/popping from the exhaust and no more hiccups from the carburetor.
As annoying it was to take it apart several times, at least I learned from all the advice given and actually going through the process of it all.
I also changed the main jet from a 165 to a 170. I didnt really notice anything from this. I dont think I needed to do this. I checked under the push rod tubes and noticed the push rods are solid after I installed the bigger jet. I was told by a local Harley tech that the push rod tubes on the bike were aftermarket leading him to believe the original push rods had been cut and adjustable push rods installed and cam was installed by how it sounds...now I'm thinking it just has the stock cam.....who knows until later when I plan on opening up the top end and then I will pull the cam cover and verify. Im just going to ride it for the time being and change the main jet back to the 165.
I appreciate everyone's input!
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