Dies when coming off throttle

[Cooter]

What RPM is it idling at? Perhaps it's just a little low and the drag of the trans makes the difference?

I agree with Crash to clean the IAC and hoses. Maybe it's slow?

What do you mean by "bog" at 2k-3k rpm "while decelerating"? A 'bog' is normally used to describe a hesitation, or slow accelerating.

2k-3k seems a really low rpm to ride around in a 1125. I know, I know... 25mph kills me too but try a lower gear.

I'm concerned that you can smell lots of fuel from the pipe. That means it's rich regardless of what the O2 sensors say. Do you have access to a wide band?

Try a different tune? The PO may have changed the pipe or something just before you got it.

 

[Cooter]

You can still check for codes even if the MIL is off

 

[DanoZ34]

Normal idle is around 1200 to 1300 in neutral. Once i put it in gear and drive off and then start coming to a stop (clutch in) the Idle will drop off from that to about 1000 or so and then die. its like i hit the kill switch almost but the bike will usually start right back up. sometimes when i was in first gear just idling down a neighborhood street or at very low throttle the bike would lose power but then surge back. it would do this like 2 or 3 times until it either cut off or i gave it more throttle. No access to wideband. The ecm has a sticker on it that says HMF in the part number and thats the pipe thats on it still. i plugged the Buelltooth up to it and there are no stored codes.

 

[ReadyXB]

datalog datalog datalog! I'd be happy to review it.

 

[Cooter]

I know a lazy IAC (IAV) would cause symptom one.

Not sure about the losing power and surging back.

Thanks ReadyXB, Datalogging would answer lots of questions!!

 

[DanoZ34]

Once I get the bike back together if I have any issues afterwards I'll get a datalog. I just replaced IAC but it wasn't bad. I had a vacuum leak around the little seals to the housing. Repaired that issue, bike ran fine for like 2 weeks of daily riding and this issue started. It got to the point where it wouldn't even maintain an idle in neutral anymore.

 

[Cosworth]

I didnt read through the rest of your thread but have you pulled plugs yet?

 

[DanoZ34]

Yeah, I replaced them when it started acting funny with the running rich.

 

[Cosworth]

Hm, I had symptoms almost exactly like yours awhile back. Ended up pulling the throttle bodies/IAC to give em a good clean, brand new spark plugs, and did a reset on the ECM/TPS and all was well in the world again.

 

[DanoZ34]

Yeah, I wish it had been that easy. The IAC seems to be functioning correctly by step count and its all clean since I replaced it less than 400 miles ago probably. Same with throttle body. Spark plugs are brand new, less than 100 miles. It ran good for a day when I replaced the spark plugs then started up again even worse the next day.

 

[Cosworth]

Do you have a cable to connect to ECM spy ect? I would definitely try clearing the ECM even if there are no codes. When mine did this there were no codes either... Long shot but worth a try if you havent already.

 

[DanoZ34]

Do you have a cable to connect to ECM spy ect? I would definitely try clearing the ECM even if there are no codes. When mine did this there were no codes either... Long shot but worth a try if you havent already.

I was thinking same thing sort of. What I've been trying to find is a Race ECU tune with the HMF pipe on it. That way I can burn the correct flash to the ECU and make sure everything is good on that end.

 

[RedDevilWheezy]

I'm having this same issue, did you ever find a fix? I don't have the time, knowledge or patience to pull the bike apart so I bit the bullet and took it in to Harley, they think it may be the fuel pump. I'm skeptical.