I have a friend who's asked me to help him get his bike running better. He has a 2007 CVO Ultra with a trike conversion. Earlier this year he took the bike to a Harley shop to get it running better. They installed cams, pipes and a Thundermax. They had the bike for 3 months trying to figure out why it just dies after it idles for a while. Finally he just picked the bike up and decided to live with it. He felt that they were just tired of working on it anyway.

Since then he has logged a couple thousand miles but the problem got worse. When he started the bike cold it would idle for 30 seconds and die. Then when he did get it to run well enough to go riding it was very hard to start when it was hot.

The day he brought it to me it was popping and backfiring when he pulled in to the garage.

It acts like a vacuum leak once it starts and when it doesn't want to start it pops back through the intake like the timing is way off.

I haven't hooked in to the thundermax yet because I have never used the software, I have experience with Power Commanders. I did spray carb cleaner around the intake and there doesn't seem to be a leak.

Any suggestions as to where to start? I don't think plugging in the stock ECM will do any good or will it? I'm pretty sure 2007's had 02 sensors but since the thundermax is installed I thought I would seek advice before tearing in to this.

Thanks for the help!

 

First things first. plug in the stock ecm dont worry bout the 02 sensors. If the bike starts and idles good you know the prob is in the thundermax. Then if the prob is in the thundermax i would start over with the tmax. download a new map and do the IAC setup function and go from ground up. make sure to save the current program tho this way if somthing is way messed up with the fresh download you will be able to resort back to the old probram.

 

by the way where r u located

 

that's an awesome shop he had work on his bike.
by him accepting the vehicle as "fixed" he probably has no recourse now


intake backfires, as you note advanced timing

can also be lean mixture

(so these can be tuner issues or mechanical faults)

and incorrect valve timing or valvetrain problem, such as intake valve not sealing

you can check valves with a cylinder leak down test, manually rotating the motor seeing at which points the valves are open and closed

mike

 

Just throwing this out there but I think a few guys have found the fuel line inside the tank cracked/leaking internally. I can't remember the complaints so it might not be be related.

 

Disturbing. That bike wouldn't have left without them getting it right.

 

If that bike has a temp sensor, swap it out. Sounds like the puter is leaning the bike out according to bogus sensor info.
Hatch.

 

Thanks for the replies, I tried the stock ECM and that didn't help. I hooked the TMax back up and the bike started and reved high for about 10 seconds and died. I started it again and tried to keep it running but couldn't. Still popping and backfiring.

mfortkamp.... live in Mt Pleasant Iowa

I don't want to mention the shop that did the work but my friend talked to the mechanic after he picked up the bike and had put some miles on it to let him know that he wasn't happy with how the bike was running and the mechanic said that if he had more time he thinks he could have fixed it but the owner wouldn't let him work on it anymore. Not sure why but that's the story.

The shop even tried a different Tmax and that didn't help. After hearing that I kinda figured they just wanted the bike out of their hair. We've all been through that kind of deal before so I guess you just get your bike and look for help elsewhere.

Is there a way to test a temp sensor before buying a new one? The reason I ask is my friend goes south for the winter and he left me in charge of doing whatever it takes to fix the bike so I'm spending his money.

Again thanks for the help cause I'm going to need it.

 

Got both service manuals? Electrical and mechanical. Betting it's gonna be something simple like a bad connection(broken pin). Best to go over all the connections first. The symptoms your describing sound a lot like the way my 07 ran when the VSS crapped out. Do the turn signals work correctly? If not, that is your culprit. Still could be a lot of things but it's best to start with the simple stuff...don't over think it...

Another thing to check is the air valve screw. 07's had a problem with them backing out...

 

The turn signals do "NOT" work properly. What is VSS?? They flash regularly for 4 seconds then rapidily there after. Here are the codes

b1121
b1122
b1126
u1016

The u1016 code showed up in the last 3 diag sections.

My friend had an LED system installed on the bike if that makes a difference?