I have a 2007 Harley Davidson Ultra Classic: S&S stealth breather, true duals with V&H slip on, cobra auto tuner, and new andrew cams. My problem is bike will not take off out of first at stop without spitting or sputter. I really started to notice it last year at Sturgis. I had a stage 1 flash and talked with Cobra rep and he told me to try something, Cobra auto tuner was meant to run with stock ecm so he thought maybe getting to much fuel at take off. I now have a stock ecm flash but still having the problem, so I took of auto tuner and it made it worse, would idle but if you cracked throttle would sputter. Put auto tuner back on. Runs fine idling and has lot's of get up and go power, but running at low speed in first or second will sputter........any suggestions, I'm ready to throw this bike off the river bridge.....if I didn't ever have to stop would be great......

 

Two words. Dyno tune!

 

^Agreed....

 

I had them same problem with my Andrew's 57 cams. I increased the VE ratios by 7% in 20-30 kpa range between 750-3500 rpms on both cylinders, that fixed the problem.

 

Oops! My bad. The VE increase was in the 0 and 2% throttle position not the lower kpa ranges

 

The cams have a huge effect and the factory mapping is based on the opening and closing events of stock cams. If the ones you have installed are significantly different, than what the stock mapping is programmed for, you will have problems.

A good way to know if you're in the ballpark is to look at the manifold kPa at idle. 32-35 ish give or take would initially indicate the cam timing is close enough to the ECM mapping settings to work. If you see 40 plus (especially heading toward 50), it's getting out of the range and you would need to get a tuner that has different maps that accommodate different cams.

However, you did change quite a bit and the stock map can't deal with it. I don't use the Cobra tuners, so I don't know what their limitations are.

 

That is exactly were I think my problem is, it only does it when you barely crack the throttle like driving in town through a 25 mph zone or slower. How did you fix that?

 

I have a power vision tuner, with any decent tuner you should be able to do it

 

Here's a quick update, so far, I think I got it fixed. After checking for leaks, pulled air cleaner off and retorqued bolts for mounting plate on air breather, running really good right now, no problems taking off in 1st gear.....

 

Im having the same problem, starting off it feels like its loading up then spits and sputters then takes off. Mine is an "09 Ultra that I just put S&S 551 Easy start cam and had it dynoed. I sprayed carb cleaner around intake to check for leaks , did not detect any. The service manager said the clutch was slipping and that it needed to be replaced, so I did problem still persist. The service manager is lost as to what the problem could be. Hunter I see you say yours is acting better, could you tell me what you did to fix it. Sorry if I stole your post, Im getting frustrated with this thing. Thanks in advance.