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Surging after high speed trips

2K views 13 replies 3 participants last post by  rbabos 
#1 ·
Ok so I have an 08 Night Rod special will just over 1600 miles on it. In the last few months I have taken two trips out where I was doing in excess of 80mph and then afterwards as I got into a cruseing section of the trip I found that the bike wanted to surge a lot at regular RPMs. If I jumped on it she would respond and take off on command and at idol it was fine but again at regular cruseing RMPs was the surging. The first time I had it happen it operated just fine the next day when I got back on it. And no issues in town until again I went out of town and ramped her up good. Any clue as to what is doing? Thx in advance.
 
#2 ·
Basically your tune is a hair lean in the 3500-4500 range to begin with or it's too rich at the higher rpms and the effects of Adaptive from higher rpm exposure pulling fuel, these trims transfer back to lower cruise rpms, for a while. It will relearn that lower cruise rpm and the surging will likely stop.
Bottom line is the tune, factory or otherwise is not centered well enough to the point where Adaptive, (long term learn) will not effect surrounding areas. If trim adjustments are too much one area it can transfer over to another rpm area. The new learned trims cover blocks in the calibration, not exact areas so not real precise.
In a nut shell the ve tables are not populated correctly for the requested fuel or the requested fuel isn't the right amount after the Adaptive tries to dial it in based on the numbers.
Ron
 
#3 ·
Good to hear and I believe your right. The bike is stock... other then the fact that the previous owner put V&H exhaust on it and I have not found a fuel pack on her. Am I right to assume that getting one will take care of my issues as well as allow me to make other changes (ie: K&N air filters and such ) ?
 
#4 ·
Not a fan of FP but something minor like this it might solve it to the point you won't notice it. It won't actually dial in the two areas as in tuning but adding more fuel will mask the light cruise area to the point it won't surge from extended high rpm runs. I'd not waist time on the filter as it really offers no gain in a stock cammed engine. Even a full blown dyno tune with a tune on the stock filter and comparison to K&N you'd be splitting hairs. Most of the claims you see are from a full tune vs crap stock tune. That stock paper filter is huge and way beyond what the engine needs for air. The K&N will also allow the engine to eat more dust as the filter media has bigger holes. This is a good thing if you actually need more air like a filter reduction size like on some SC or turbo installs but in this case, size for size the bigger holes do very little for WFO gains.
Ron
 
#5 ·
Ok thx for saving me some money on the filter, so what would your suggestion be for tune or fuel management system? I don’t race and don’t need anything crazy performance wise but do hit the highways and a few twisty roads being near Route 66 it can get a bit spirited out there. I don’t plan on any real performance mods in the near future either.
 
#6 ·
I don't like recommending piggy back devices as a rule, however, based on no future upgrades and it doesn't sound too terrible enough to require a full dyno tune which is the best method, the PC3 might be a good choice for what you need. You can dig deeper into the FP but there are a lot of bad reports with it, maybe asking it to do too much. It should work for mini adjustments like you need however. I have no hands on experience with either of these as I only play with flash tuners. There are a lot of bikes running around with the PC however with good results.
Ron
 
#7 ·
After some looking around I found a tune/dyno shop that specializes in Harley Davison not too far from me so I’m going to be calling them tomorrow to set up an appointment for the Night Rod. Thx again for the insight and recommendations.
 
#8 ·
Watch out on that shop. They may specialize in Harley's but the V-Rod is a different animal and requires different procedures etc. I had mine tuned by a highly respected shop in Pinellas Park Florida and the thing ran so poorly I backed the tune off.
'
If you publish where you are located maybe some forum member can point you to a V-Rod friendly shop.
 
#9 ·
Watch out on that shop. They may specialize in Harley's but the V-Rod is a different animal and requires different procedures etc. I had mine tuned by a highly respected shop in Pinellas Park Florida and the thing ran so poorly I backed the tune off.
'
If you publish where you are located maybe some forum member can point you to a V-Rod friendly shop.
 
#12 ·
So a few of the “Dyno/Tuning” shops I have looked into want to use a Dynojet or PC... to do the Dyno and tune. I’m thinking this is not what your suggesting to do? Or is that just the means for which they will use the dyno to get an appropriate map for me? Sorry I have never had to tune a bike so all new to me.
 
#14 ·
Yes, instead of you buying the PV unit outright , they will charge you the license fee and tune with one of their units. PV, TTS will only tune the bike it first marries too, the additional license is needed for each additional bike after to tune with the same PV unit.
Ask for a copy of the final tune on flash drive, should you at some point get your own PV unit. You can retrieve the existing tune in the ECM also which will be the same one on the flash drive. All for the day should you decide on upgrades, or if your ECM blows up, so you won't need to retune again.
Ron
 
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