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Lack of Power

The way the bike is right now is in it's factory stock configuration, that is no fueler boxes, no add on black boxes, pure stock ignition system,,ignition is triggered from the ECM,, factory map and look up tables. ?.

Hoople, Thanks for your comment.
I have a Terminal Velocity 3 installed at the moment due to the S&S 510GD cams. It has been on for the last 10,000 miles without a problem. I had switched to the Thundermax with Autotune after the problem started, thinking the TV3 had given up and to improve overall performance but I got the same, if not a bit smoother, poor performace so I eliminated the mapping as a possible cause.

All the HD tech could suggest is adding a screaming eagle map because he can't find the problem with his diagnostics machine thingy. If a fault doesn't show up, then there isn't one. I now know why they changed the job title from "Mechanic" to "Technician". Long ago a good ear and experience was enough.
 
I have been reading this forum for the last six months and have to thank you guys for a lot of info. This is the first time I have posted so here goes.

I have a 2003 Ultra with 38000 mls, S&S 510 GDC & TMAT but seem to have lost power suddenly. Idles ok but lacks acceleration as it did. When I hit 55-60 mph noticable that the engine is struggling. Tested compression, leads, plugs. Reset adjustable rods...no change. Front cylinder plug a bit black with carbon and front exhaust covered inside with the stuff. Rear cylinder seems fine. Even took TMAT off and went back to HD ECM but the same result just slightly worse. Had the dealer check and he said it was the injectors so had them replaced but no change, still the same. I suspected the coils but he said the coils and HT leads were normal.
That said he is not a good dealer but is close and I though he could at least diagnose the problem.

So what's going on??? Would appreciate your thoughts or comments.

Willie

Just for grins, put in a new set of stock plugs. I've read below and didn't see that you have tried that. It could be that the plug is breaking down under load, which, will let it idle fine but not fire correctly under the extra load in the upper rpms. simple and cheap it may not fix it but you've eliminated the plugs as the culprit, process of elimination.----jack :s
 
Just for grins, put in a new set of stock plugs. I've read below and didn't see that you have tried that. It could be that the plug is breaking down under load, which, will let it idle fine but not fire correctly under the extra load in the upper rpms. simple and cheap it may not fix it but you've eliminated the plugs as the culprit, process of elimination.----jack :s

Hi Jack,
Oh if it was only that simple. That's the first thing I did. Bought a brand new set of standard HD plugs. Tech then changed them out for a new set of Screaming Eagle ones, also replaced the MAP sensor, IAC sensor. Well so he told me! (didn't charge for these either)
Thanks anyway, sometimes the solution is staring you in the face. That's why I came on here so appreciate all the comments...some I hadn't thought of.
Willie
 
An update for those who were kind enough to post replies:

Rear exhaust valve so slightly bent it leaked when the engine heated up so loss of power. It was suggested to me that when the drive belt snapped that the engine may have overrevved an nicked the valve???

Anyway, both heads are off and sent away to be ported & polished then fit with stronger valves & springs.

Question: Should I consider a 95" big bore kit stage 1 (29774-02B) while I am at it.
I already have S&S GD 510 Cams so does it seem the best next step since the top ends are off.

Appreciate your comments.
 
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