I have an '09 Nightster 1200, V&H VO2 naked intake, V&H Short Shots Staggered Exhaust, V&H FuelPak with "proper Map" Mechanic confirmed no vaccum leaks exhaust is sealed etc. When cruising in any gear any speed except cruising at like 70-75. I get a spudder/studder as if either a plug isnt firing right, jets gummed up (they arent) or throttle isnt working right. But when I can throttle out and accel right out of it. anyone else with this issue, and if so what fixed it. I saw 1 guy said something similar was his ET sensor?

 

probably bad advice:

Have you run seafoam through it or checked you plugs?

 

yes, i have run a few different ones as well doesnt fix it, i have changed plugs twice they are burning optimally.

 

This issue could be many things and I don't think the internet is going to help you as it (we) would just suggest throwing parts on.

Your bike is modified.

Suspect would be the fuel pack and its wiring or intake.

You need to duplicate the issue.
It could well be ignition from your description and the voltage regulator seems to be a common failure for example. Coils, sparkplugs wires and so on.

It could well be fuel.
Dirty fuel lines, injectors, filters. Carbon build up in combustion chamber causing a ping hence the Seafoam mentioned above.

Plug reader doesn't seem viable as this shudder is intermittent so yes their look is an average and OK.

Duplicate the issue at a shop so you can trace it is the first step IMO. Good luck

 

Just a thought, your not lugging it are you?
Try dropping one gear at any given speed and see if it still sputters.

 

Used the Lucas ethanol cleaner once and the bike ran like crap. Unfortunately I added it to my VROD also at the same time and the same thing happened and I even got the check engine light. Be careful with those additives/cleaners. Took two tank fulls to clean it up.

Try a different map (close to the one you have) with your FuelPak and see if you get any changes. Your map could have gotten corrupted.

 

thats about the only thing i know im not doing is lugging. working with V&H to see if changing some numbers may help
problem is it was doing it a little before upgrades

 

Loose primary chain? Riding with RPM too low? Fuelpak lean at cruise? If the primary chain is set right and you're not lugging it try asking V&H for a map with slightly richer light throttle values and see what that gives you.

 

chain is good, im thinking too lean, V&H gave me a few new numbers to try we shall see

 

Interesting to know if the modes they have you adjust match up to the guesses in this thread:


https://www.hdforums.com/forum/sport...k-project.html