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CVO Technical => Twin Cam => Topic started by: navyret2001 on July 21, 2018, 03:41:27 PM

Title: CVO stumbles
Post by: navyret2001 on July 21, 2018, 03:41:27 PM
My 2016 CVO limited recently had a cam upgrade SE 585 and a new tune. It runs great, sounds great ....but now has a new issue, it "stumbles" when making a hard turn and accelerating back up to speed while still in the lean of the turn, almost like it's losing fuel flow or pressure. Anyone out there had anything similar?
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Title: Re: CVO stumbles
Post by: shaochieh.young on July 21, 2018, 05:00:07 PM
Was it a Harley default tune or a dyno tune?


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Title: Re: CVO stumbles
Post by: navyret2001 on July 21, 2018, 09:18:55 PM
SE racetuner was dyno'd at a local tuner who has done several of my bikes in the past and does all of our local HD dealership work. This is the second time I've had this happen and it seems to be late in to the ride, after several hours of riding and here lately temps in SW Louisiana have been in the high 90's...frustrating to say the least!!
Title: Re: CVO stumbles
Post by: shaochieh.young on July 22, 2018, 03:43:34 AM
Obviously this didn’t happen right after the tune?  No engine code? 


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Title: Re: CVO stumbles
Post by: navyret2001 on July 22, 2018, 05:57:14 AM
No it was tuned a few days ago, and no codes...my frustration!
Title: Re: CVO stumbles
Post by: RonandJanet on July 22, 2018, 01:20:38 PM
Since this only happens on hard turns I would think the tune should be OK.  I know this is probably stupid but is it possible you were low on gas?  I tight turn could cause the gas to move to the side of the tank.  Just a thought.
Title: Re: CVO stumbles
Post by: grc on July 22, 2018, 04:17:03 PM
Since this only happens on hard turns I would think the tune should be OK.  I know this is probably stupid but is it possible you were low on gas?  I tight turn could cause the gas to move to the side of the tank.  Just a thought.

Not stupid at all.  Harley tanks do not have internal baffling like cars do, so the combination of a hard turn and acceleration with a low fuel level could in fact force the fuel away from the pickup, which is in the front center of the tank. 

Jerry
Title: Re: CVO stumbles
Post by: Twolanerider on July 22, 2018, 05:12:55 PM
Since this only happens on hard turns I would think the tune should be OK.  I know this is probably stupid but is it possible you were low on gas?  I tight turn could cause the gas to move to the side of the tank.  Just a thought.


Also possible and along with this is perforation in the pressure line inside the fuel tank.  A surprisingly common problem as the plastic lines seem not to always appreciate ethanol fuels.  Depending on size of the hole while the line is submerged in fuel the problem doesn't present.  Low tank or enough of a turn and the hole isn't submerged anymore and fuel pressure drops.
Title: Re: CVO stumbles
Post by: navyret2001 on July 24, 2018, 07:48:11 PM
I had a half tank of fuel, so I don't think that was my issue. Discussed my issues with dealer I think I might be pulling race tuner installing the super tuner and stacking the HD auto tune.
Title: Re: CVO stumbles
Post by: Nocvo on July 25, 2018, 04:00:33 AM
I had a half tank of fuel, so I don't think that was my issue. Discussed my issues with dealer I think I might be pulling race tuner installing the super tuner and stacking the HD auto tune.
Race tuner and super tuner are the same thing if the lingo is being used right, the wide band auto tuner is a waste of coin, twolanerider has a point I'm thinking.
Title: Re: CVO stumbles
Post by: grc on July 25, 2018, 08:55:50 AM

Screamin' Eagle Race Tuner = SERT  (Off-road Only)
Screamin' Eagle Pro Super Tuner = SEPST   (Off-road Only)
Screamin' Eagle Pro Street Tuner = SEPST  (Street Legal Only)

Notice they have two acronyms that match but do not refer to the same system.

Which system is currently on the bike, street legal or off-road only?  The street legal system does not allow for modifying the part throttle settings where the emission controls are required, and if that is where you need an adjustment and you're running that street legal system you can't do it.  The so-called auto tune can't either.

Have you considered other possibilities such as a T-MAP sensor problem that manifests after a long ride in hot temps?

Jerry
Title: Re: CVO stumbles
Post by: JKM on July 25, 2018, 12:00:12 PM
talk to your tuner....he will know best if the issue is with the tuning module.  If you have the street legal version, and looking to change to a "off-road" version, got with his recommendation and not the dealers.  This is his area of expertise and he probably has a preference of what he likes to work with.
Title: Re: CVO stumbles
Post by: navyret2001 on August 11, 2018, 12:22:44 PM
I have the pro tuner, and it was a tuning issue, I guess everyone has a bad day! Bike is back running great! Tuner "missed" in a couple of areas that were way to rich that caused my issues. Thanks to everyone who responded!
Title: Re: CVO stumbles
Post by: grc on August 11, 2018, 02:21:34 PM
I have the pro tuner, and it was a tuning issue, I guess everyone has a bad day! Bike is back running great! Tuner "missed" in a couple of areas that were way to rich that caused my issues. Thanks to everyone who responded!

Harley calls both of them "Pro", one is the Super tuner and the other is the Street tuner.  I'm assuming you have the Super tuner.

Jerry
Title: Re: CVO stumbles
Post by: SDCVO on August 11, 2018, 10:19:29 PM
this may sound crazy about a month ago I was going to Born Free rally when my bike started stumbling also. I run a S&S 124 so while i was walking around I went to the S&S booth and asked the tech guy. It was packed and everyone was trying to talk to the guy at once but he said "sounds like spark plugs or plug wires". I kinda just thought he was just coming up with a quick answer so he could help others. As I rode back about 250 miles the stumbling was getting a bit worse but not consistent. Talking to some buddies I got many opinions about what it could be and when I told them what the guy said they all said not a chance, that hardly ever happens now with the Sreamin Eagle wires I use or plugs. Took it in the shop next week and when the tech went to remove wires the front came off in his hands. Changed the wires and I was good to go. Tech also was surprised that ended up being the issue.
Doubt thats your problem but never know..
Title: Re: CVO stumbles
Post by: Joel on August 17, 2018, 12:21:20 PM
Everyone should check the plug wires, the routing puts the front cylinder plug wire against the fuel tank and the wire gets rubbed enough that over time the voltage shorts to the fuel tank and will cause a misfire.
Mine were replace awhile back under warranty, I have shown many riders that the wire is rubbing on the tank.
All that needs to be done to correct or prevent this condition is to push the plug end over enough to bend the connector to clear the tank.
Title: Re: CVO stumbles
Post by: RonandJanet on August 18, 2018, 07:37:18 AM
I put some of that black plastic spiral wire protector over my wires.  I do agree plugs etc. can cause stumbling or lack of power on acceleration but this is happening only on a hard lean?  I guess maybe the lean could cause the wire to shift slightly to expose more damaged area.  Worth checking it out closely.