The dreaded carb cough and interesting findings

[gearbanger]

Originally Posted by rejeanprimeau

No VOES on a 2006, Map sensor. You're sure the plugged vacuum line didn't went to the tank valve?

The now plugged vacuum port on the carb did in fact lead to the tank valve. Early on in my diagnosis I thought the vacuum operated petcock was faulty and leaking fuel into the carb, so I went to a non-vacuum operated petcock and plugged the vacuum port with a cap.

[wedge]

Originally Posted by gearbanger

The now plugged vacuum port on the carb did in fact lead to the tank valve. Early on in my diagnosis I thought the vacuum operated petcock was faulty and leaking fuel into the carb, so I went to a non-vacuum operated petcock and plugged the vacuum port with a cap.

Those standard plugs crack and leak every few months, unless you pull the carb and plug that port solid. Once they start leaking it will start popping again, so you will always know when it's time to replace if you are paying attention.

[bustert]

there are many things that can effect timing. some carbs have adjustable stroke and one needs to record where it rod goes. older carbs had 2 checks in the circuit, one in the cover and one in the bowl. they deleted the cover ball for emissions, also note the newer carbs do not have a leak jet. the tunnel is there but not drilled. that leaves the check in the bowl.
if you stroke the pump while holding the bowl with liquid and observe the inlet to the pump, you will see some return when pressuring up the nozzle. if this leakage to too great, it impedes the stream and alters timing.
also, if there is any drag in the linkage as it is free floating, it will alter timing same as a bad return spring.
i get a lag every now and then but i know my issue, the float bowl needs replacing as the check is not doing its job so at times the squirt is delayed.

[gearbanger]

Originally Posted by bustert

if this leakage to too great, it impedes the stream and alters timing.
also, if there is any drag in the linkage as it is free floating, it will alter timing same as a bad return spring.
i get a lag every now and then but i know my issue, the float bowl needs replacing as the check is not doing its job so at times the squirt is delayed.

This is intriguing to me...

I had purchased a CV performance float bowl replacement but after installing, I found a fuel leak below. Their replacement does not have an overflow nipple which is concerning given sometimes your float needle will stick (hitting rough potholes) and I chose to remove it and reinstall the original bowl. I threw the new CVP one back on for reconfirmation via test ride given your comment and before riding off I wanted to visually check the pump performance, and to my surprise, she didn't squirt. Not a drop. threw the OG one back in and she fired away with a strong squirt down the throttle body as it should. Has to be a defective product in some way, shape, or form. So... with no good comparison on float bowl performance with a new product I cannot say for sure but it is indeed possible the check valve in my original float bowl is faulty at some point but hopefully I can get a replacement from CVP.

After some more riding, I had a few more farts... sad to report.

Made a few adjustments today and am currently running 48 pilot, 3 turns out IMS, 175 main, CVP needle with x2 0.20mm shims (***undrilled slide***) and having a fart once in a while.

Torn between leaving it to the Harley gods and just letting it go, or to keep fuxxing with it, change the intake and exhaust seals (AGAIN) and continue to diagnose.

This is a constant reminder on my way to work as to why I'll stick with working on marine DIESEL engines as my profession

[Tomcatt]

Originally Posted by gearbanger

After some more riding, I had a few more farts... sad to report.

Made a few adjustments today and am currently running 48 pilot, 3 turns out IMS, 175 main, CVP needle with x2 0.20mm shims (***undrilled slide***) and having a fart once in a while.

You might want to check your float level. If it's low it can give the symptoms you're experiencing.

[gearbanger]

Originally Posted by Tomcatt

You might want to check your float level. If it's low it can give the symptoms you're experiencing.

Triple checked float level and set as per manual specifications. In the process of removing and replacing the float bowl a handful of times I would kill the engine, prep for bowl removal, then close the petcock and remove. Every time the bowl came off it was full up… seems to me it’s not running rich but would I want to consider richening the float level?

[Tomcatt]

Originally Posted by gearbanger

Triple checked float level and set as per manual specifications. In the process of removing and replacing the float bowl a handful of times I would kill the engine, prep for bowl removal, then close the petcock and remove. Every time the bowl came off it was full up… seems to me it’s not running rich but would I want to consider richening the float level?

I'd say it's worth a try at this point. It will make things better or worse and you can always put it back where it was. More info is always good.

[wrkdWS6]

It’s been a while since I’ve had a CV40 carb, but a 48 jet at 3 turns out sounds way too rich for an 883. I’ve run less rich than that with a cammed 1200 at sea level. Every bike is different but I feel that’s masking the true issue. I’m more used to Mikunis and S&S carbs nowadays, need to jog my brain on what to check here.

Sorry if I missed it, but are you running drag pipes or an exhaust setup with baffles removed?

I’d check out the idle drop method and see where you get with that. Before doing that, with bike fully warmed up, crank the throttle a few times and pay attention to how it drops back down to idle. If the rpms hang a bit before dropping to idle idle mix is lean, if rpms drop below idle rpm (sounds like surging) then comes back to idle, it’s too fat.

Edit: Have you checked to see if the silver needle jet is right side up? Can easily install that upside down by accident.

[gearbanger]

Originally Posted by wrkdWS6

Sorry if I missed it, but are you running drag pipes or an exhaust setup with baffles removed?

Edit: Have you checked to see if the silver needle jet is right side up? Can easily install that upside down by accident.

I have screaming eagle exhaust pipes installed… what should I be checking for if the baffles are still installed or removed? I think the baffles are still in but is it easy to visually confirm if they are or are not?

Yes I’m 110% sure the needle jet is right side up but will check again.

I’m going to go ahead and replace the manifold gaskets AGAIN. I had bought the bike into my local Harley dealer to see if they could figure it out a few months ago and we all know how that experience went… it’s very possible they didn’t do what they say they did, or they did and performed an awful execution of changing them out. When looking at the manifold and flange, it’s obvious there’s a bit of an alignment issue so I’m going to swap them out again and see if I can’t get it nut on.

Furthermore, when checking plugs (I know the bike is jetted pig rich at idle) my front spark plug reads clean and the rear is carbon fouled. Might be a tell tale that one of the seals is bad.

Wish me luck and will update!

[IXL2Relax]

Originally Posted by gearbanger

When looking at the manifold and flange, it’s obvious there’s a bit of an alignment issue so I’m going to swap them out again and see if I can’t get it nut on.

Furthermore, when checking plugs (I know the bike is jetted pig rich at idle) my front spark plug reads clean and the rear is carbon fouled. Might be a tell tale that one of the seals is bad.

YEP - Tell tale sign of a leak in manifold-to-head seals is having one plug clean & the other one fouled.

The CLEAN PLUG is on the cylinder with the BAD SEAL --- It is getting extra air while you are using that 48 slow jet - the extra air makes that front fuel mix more correct --- while the rear plug gets all that extra heavy fuel in the mix but no extra air to compensate for it...

And you're right, it is important to align the manifold NOT ONLY to the heads but to the right spot for the carb... Spend some extra time mounting the carb without the carb/manifold seal so you can see that the carb fits perfectly into the throat of the manifold when the manifold is bolted down to the heads. It will pay off later when you finalize the carb install (with the seal) and align it for NO AIR LEAKS...

Good Luck...

Be sure to read over the Sporsterpedia section on the CV40 carb:
http://sportsterpedia.com/doku.php/techtalk:evo:carb02

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