My '96 UC has been experiencing intermittent problems for the last month or so. The Engine light was coming on occasionally. That progressed to the light coming on frequently and the bike running pretty rough at times. It showed a failure code of 55,ECM Failure, so I replaced the year-old 97B ECM but that had not effect on the problem. i took the bike to my independent mechanic and he found problems with wiring connectors, the Intake Air Temperature Sensor and the Throttle Position Sensor. After addressing those problems, the bike still ran very rough. The mechanic said the Engine Temperature Sensor was also erratic on his last run but he had run out of time to work on it (other bikes waiting). I picked up the bike Wednesday afternoon and didn't think it was gonna get me home. I ordered the ETS and put it on last night. Finished putting everything back together this morning and went for a ride. Much better without any Engine light issues but the bike ran poorly at 2500 rpm in all gears. Also had significant lean fuel popping on decel. I took it to another tuner this morning who put it on a dyno. Air Fuel Ratio was 18:1 from idle up to 2000 rpm or so and didn't get to 14 until about 3000 rpm (where it had been running strong). I got back home and tried tweaking the SE Race Fueler RPM Transfer points and fuel add pots for idle and mid range. Did this by listening to the engine as I ran it up and down the rpm range. Went for a ride and the lean fuel popping and rough spot at 2500 rpm where greatly improved. Still not perfect but much better. I'll take it back to the tuner and put it back on the dyno and have him tweak it in properly. I'm glad to have this one straightened out. This all had to happen while the Forum was in the tank,of course. I really felt lost not being able to get on here and ask some questions. I learned a ton from all this and will be able to do a better job of diagnosing a problem like this next time.

The dyno numbers on my bike are 65 HP and 76 LB-FT of torque. First time I've had it on a dyno where I actually got the numbers. They're not eye-popping by any means by probably better than I expected.

For anyone interested, this is what's been done to the stock bike I started with:
SE A/C
SE-3 Cam, Comp Cam lifters, Adjustable pushrods
Heads ported and polished
SE Race Fueler
Samson Rolled Thunder slipons (by previous owner)

I know it's a long post but it would have saved some bucks and a bunch of time to have seen a writeup like this a few weeks ago. I'm not posting this to brag on my bike or my very weak wrenching skills. It's just to maybe help somebody else who might have similar problems.

Anyway, ride safe and often.

 

I had an issue where the bike would not stay started when cold and had to replace the ETS and it runs alot better now. The mods i have done are to install Supertrapp slipons. I am considering a cam and pushrod upgrade but not sure which one I will go with. What kind of mileage are you getting with your current setup? Just curious. I currently average aroudn 43mpg.

 

I average about 40-41 commuting to work, about half on open highway and half in moderate city traffic. On the highway at cruising speed it drops to about 37. I went with the SE-3 cam because I just wanted a little more giddyup, not a hotrod. It met that requirement well.