I just had a local independant HD shop convert my '05 EGC (TC88 35000 mi) to a set of gear driven cams. The cams are a small upgrade but mild enough not to have to change the valve springs, I also added a Power Commander III. After the conversion the engine sputters when MAINTAINING speed/rpm on level roads, but not under the slightest load or when decelerating. The sputtering only happens between 2000 & 3000 rpm, not below or above, and the throttle position is less than 10%. The plugs & wires were replaced with new, the wires made a difference but the sputter was still there. The Power Commander was adjusted to six different settings with no noticable change (we were in contact with Dynojet during all this). We finally disconnected it & reconnected the factory ECM but there was no difference, the sputter was still there (now thinking a pre-existing condition, possibly masked by the chain drive). A compression check showed less than 10% difference in pressure between the cylinders. Anyone have any experiences/ideas about this problem?
Gregm

 

Im kinda leaning toward the springs,,,,,,i was thinking if the springs are worn in at 35000 miles , then even a little more lift might cause them to be weak in a certain rpm range due to being compressed even if its a little bit more,,,,,,maybe the stock springs were set up right at their limit of travel,,,and since they have that miles on em they have weakened up a bit ?????? sure sounds like floating to me,,,,,,,,

or maybe a lifter issue could have lifter leaked down,,,,,

On the other hand have you checked to see if you have an intake or exhaust leak,,,,,simple to check and that would do it too,,,,,

 

I asked the indy when we did the work if new springs were needed with the new cams and he said he's never had to before, this is a drop in cam set (Head Quarters 034G). But I'll run the weak/worn in spring idea by the indy. We installed new lifters and we were thinking about checking for leak down if we couldn't find something obvious. Another detail...I had some "cored out" HD slip-on mufflers on at the time of the conversion, I switched to the stock slip-ons to see of it would make a difference.....nada.
Gregm

 

Yeah it could be that they are just a bit on the weak side or maybe one of em lost a coil or is about to ...??? I will bet that sooner or later there will be a bunch more opions on the way...........keep us informed ,,,,,kind of a stumper this one.....

 

Will do Shank, it's a stumper alright. I pulled the new plugs after 70 miles and the rear hole plug has a black fluffy deposit all over while the front plug has the nice grey color you'd expect of a well running engine. I'm thinkin' either a weak coil (as rare as that is) or an injector problem. More to come, film at 11.
Gregm

 

Problem solved! I was running "cored" HD pipes, and the Power Commander downloads we used did'nt match my set-up well enough, it was way too rich across the board. We installed a set of Python slip-ons so the engine could breath again and it had a lot more power but the sputtering was still there. Saturday I took the bike to Mike Velasco at The Brothers Honda in Bremerton (Wa) and he worked magic with his state of the art dyno-tuner. The sputter is gone and the bike is putting out 78 hp with 88 ft/lbs of torque. Mike truly loves his work and was explaining everything to me as he dyno-tuned the PC, I recommend him for any dyno work. Thanks to everyone who gave input on my problem.
Gregm