c.v. carb issues
Thread Starter
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Tourer
Joined: Oct 2008
Posts: 499
Likes: 0
From: cambridge, ontario
c.v. carb issues
hey all
last night i finally took the pan out for a test ride after doing some work thats unrelated to my problem.
the bike fired up no problem, first kick. ran like crap, until it got to operating temps. i rode it for a few miles, (kilometers), about half an hour of good riding. felt great...
when i got home i figured it was idling a little fast, so i went to adjust the idle mixture screw. turned it in all the way, and no difference at all. i can turn it out all the way or in all the way and nothing changes.
i dont get it???
i can shut the bike down, at any temperature, and fire it backup with a single kick.
the bike is running great so i dont want to tear it apart AGAIN if i dont need too. its not idling too fast, fast is better than slow, but want to slow it down some.
can someone explain whats going on here?? thanks a ton.
last night i finally took the pan out for a test ride after doing some work thats unrelated to my problem.
the bike fired up no problem, first kick. ran like crap, until it got to operating temps. i rode it for a few miles, (kilometers), about half an hour of good riding. felt great...
when i got home i figured it was idling a little fast, so i went to adjust the idle mixture screw. turned it in all the way, and no difference at all. i can turn it out all the way or in all the way and nothing changes.
i dont get it???
i can shut the bike down, at any temperature, and fire it backup with a single kick.
the bike is running great so i dont want to tear it apart AGAIN if i dont need too. its not idling too fast, fast is better than slow, but want to slow it down some.
can someone explain whats going on here?? thanks a ton.
Seasoned HDF Member
Joined: Aug 2007
Posts: 21,735
Likes: 17,571
From: Driftless Area
CV on a pan? Assuming you have an adapter to the intake manifold to make it fit, check along there for air leaks like FastHoss said.
Not sure what you mean by "idle mixture screw"........you should be adjusting the "idle speed screw" (the one to the cable guide). Check to make sure the cable isn't hung up where it enters the holder near the cable guide.
Not sure what you mean by "idle mixture screw"........you should be adjusting the "idle speed screw" (the one to the cable guide). Check to make sure the cable isn't hung up where it enters the holder near the cable guide.
Thread Starter
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Tourer
Joined: Oct 2008
Posts: 499
Likes: 0
From: cambridge, ontario
yes im running a cv carb untili get enuf cash for a s&s super e. lol.
yes i have an adapter to make it all fit.
by ide mixture screw i mean the set-screw at the bottom of a c.v.carb that adjusts the idle speed.
whats the best way to check for an air leak other than aerosal spray?
and thanks for the replies!
yes i have an adapter to make it all fit.
by ide mixture screw i mean the set-screw at the bottom of a c.v.carb that adjusts the idle speed.
whats the best way to check for an air leak other than aerosal spray?
and thanks for the replies!
Road Warrior
Joined: Jan 2010
Posts: 1,597
Likes: 0
From: South Jersey
I had the same thing on the CV on my 99 RK. I was used to S&S carbs. When you turn that mixture scew the idle would immediately change. After knocking out the aluminum cap that covers the idle mixture screw on the CV I tried adjusting it like the S&S carb. Turning that screw in or out didn't change a thing. So I set it at 1 1/2 turns from bottomed out and never adjusted it again.
I tried everything with that stupid carb. I put the thunder jet kit in it, no change in performance. Put the thunder slide in it and it ran terrible. The guy at the shop who sold it to me told me afterwards most people just return the thunder slide because it's too light (composite plastic slide rather than a heavier aluminum slide)and just gets sucked up into the wide open position as soon as you crack the throttle open causing the bike to just bog and blow black smoke because it's just dumping fuel.
I finally just put a Mikuni HSR42 on. Carb issues are non existant with that carb. On a pan though, I wouldn't run a Mikuni (just wouldn't look right). I'd go with the Super E.
I tried everything with that stupid carb. I put the thunder jet kit in it, no change in performance. Put the thunder slide in it and it ran terrible. The guy at the shop who sold it to me told me afterwards most people just return the thunder slide because it's too light (composite plastic slide rather than a heavier aluminum slide)and just gets sucked up into the wide open position as soon as you crack the throttle open causing the bike to just bog and blow black smoke because it's just dumping fuel.
I finally just put a Mikuni HSR42 on. Carb issues are non existant with that carb. On a pan though, I wouldn't run a Mikuni (just wouldn't look right). I'd go with the Super E.
Seasoned HDF Member
Joined: Aug 2007
Posts: 21,735
Likes: 17,571
From: Driftless Area
Bottom? The screw you should be adjusting is on the side - #354 on the diagram. That screw that you are talking about (under the aluminum plug) is about three full turns out on mine. Shouldn't affect idle speed, but will affect warm-up time and lean conditions you describe.
If you have an air leak, the plugs may be light tan color, but spraying a little WD-40 around the intake joints would be better.
If you have an air leak, the plugs may be light tan color, but spraying a little WD-40 around the intake joints would be better.
Last edited by RHPAW; Jun 15, 2010 at 02:40 PM.
Outstanding HDF Member
Joined: Aug 2008
Posts: 3,078
Likes: 6
From: Michigan
Sure you didn't "adjust" the accelerator pump instead of the idle? (Idle screw touches the half moon plate that your throttle cables attach to, and immediatly changes the idle when turned, it's the same as turning the throtle)
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Road Captain
Joined: Nov 2008
Posts: 654
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From: Vancouver Island, BC
I've had several of these apart lately, from "92 to '96 and in every one of them the accelerator pump diaphragm was cracked and leaking. (part # 264 in above diagram)
After replacing this I could now adjust my idle mixture screw. Only takes about 2 minutes to change. You can leave the carb on the bike.
After replacing this I could now adjust my idle mixture screw. Only takes about 2 minutes to change. You can leave the carb on the bike.
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Road Warrior
Joined: Jan 2010
Posts: 1,597
Likes: 0
From: South Jersey
Bottom? The screw you should be adjusting is on the side - #354 on the diagram. That screw that you are talking about (under the aluminum plug) is about three full turns out on mine. Shouldn't affect idle speed, but will affect warm-up time and lean conditions you describe.
aside from external air leaks, Another problem area on CV's you can check is the Diaphram under the top cover. Make sure it doesn't have a tear or pinhole in it. But beware, If it's old and spongy it will be hard to get back into position. Sometimes you pop off the cover it baloons out to much larger than the original size.
Last edited by BikerV; Jun 15, 2010 at 04:19 PM.
Ultimate HDF Member
Joined: Oct 2007
Posts: 7,562
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From: Palm Harbor fl.
It's on the bottom, you have to remove this aluminum plug to access it. #354 on the diagram is just the bracket mounting screw, #150 is the idle speed screw, it doesn't change the idle mixture. But then again, On a CV carb the idle mixture screw doesn't seem to change the mixture either Lol.
aside from external air leaks, Another problem area on CV's you can check is the Diaphram under the top cover. Make sure it doesn't have a tear or pinhole in it. But beware, If it's old and spongy it will be hard to get back into position. Sometimes you pop off the cover it baloons out to much larger than the original size.
aside from external air leaks, Another problem area on CV's you can check is the Diaphram under the top cover. Make sure it doesn't have a tear or pinhole in it. But beware, If it's old and spongy it will be hard to get back into position. Sometimes you pop off the cover it baloons out to much larger than the original size.