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03 FLHTCUI
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375 Posts
Discussion Starter · #1 ·
When I joined the forum, I vowed I would not ask questions about the Trike because there are not many of us out there, and did not want to waste bandwith. I think I have found kind of an exception. Here is my question:

I had a Stage I done (Screamin Eagle Touring Pipes and air intake, and the obligatory re-flash) on my 03 Ultra. In hot weather, I get significant "popping" on decel and an occasional pretty loud backfire. I ask the dealer to check the plugs color and he says no problem. They suggested the bike is running lean, but would not cause problems. In cold weather, I get no backfire, but still some (but less) popping. OK, the question - can I ask the dealer to "rent" me a SERT or some other device and have them "rich-up" the fuel system (I assume this would be thru reprogramming the ECM), then test ride the bike to see if it helped? In other words, can a good tech tune the bike without a dyno? Maybe I should ignore the issue, the popping sounds kinda cool, but the backfire does not sound right. Would appreciate any suggestions.

Ride Safe.
Walt
 

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Retired USN
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61 Posts
Have you thought about seeing if a car dyno could strap your bike down good enough to do the run?
 

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03 FLHTCUI
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375 Posts
Discussion Starter · #3 ·
To tell ya the truth - no. Would a car dealership have the "stuff" to tune the bike, or would I take a SERT or other device with me? I think I would have to do that. I am by no means a wrench, or anywhere near that, so I would need to have somebody qualified help out if that was a possibility.

Ride Safe.
Walt
 

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Premium Member
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1,163 Posts
Back fire is different than the lean popping. Maybe you have an exhaust leak? I would have a tech at the dealer road test the trike. You can enrichen the lean running engine with either a DFO, PCIII, or SERT. Do a search on each one, to learn about them. I had a DFO, which worked very good, except I couldn't get the pinging to go away, as I have high compression pistons, so I bought a SERT(check the dealers who have it for 20% off MSRP). I studied other people's tweaked maps, and read all I could, and found if you find a SERT calibration map close to what your bike's engine and mod are, then take the Air/Fuel tables and enrichen them (14.5 to 14.1), and cut the decel enrichment tables by 50%, your bike will run pretty good, and you won't get any popping. Be sure to keep checking the spark plugs. I would also call the trike builders, and ask what they have used to dyno their trikes. Good luck. Ride safe.

Thorns
 

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Banned
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21,644 Posts
I am pro EFI. But could replace with carb. People were tuning carbs before dynos.
 

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Retired USN
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61 Posts
"If" They can actually strap the trike down then they could do a run in 4th gear and give you an Air/Fuel (A/F) read out that you could use to help with your tuning. With the A/F charts a bike turner could get you pretty close.
 

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Premium Member
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459 Posts
I'd look at one of the daytona-twintec units. As far as renting a SERT from the dealer you can't do that. Once a SERT is installed it is married to that particular bike and can't be used on any other bike.
 

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Highly Seasoned Rider!
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4,884 Posts
GrayRider said:
Consider a DFO. They can be picked up for around $150 and richen it up.
Info

I second the motion. A DFO would be easy for you to install and you could tune it yourself. Since you think you simply need more fuel, the DFO would be a good choice. I intend to get one myself if I ever change to a gear drive with a mild cam.

Tuning the trike would be no different from tuning a solo bike. Don't be afraid to ask questions. I like trikes and sidecars myself. :)
 

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378 Posts
My indy put in a new dyno about a year ago, for quads. It is the same as the one used for bikes(has a brake to put a load on the motor) but has 2 rollers and the front wheel clamp can be moved to accomodate any type front end. Tuned my Ultra trike right in. Might check around your area and see if anyone has one.
 

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I'm gonna powder his nose
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537 Posts
You state:
In hot weather, I get significant "popping" on decel and an occasional pretty loud backfire.
In cold weather, I get no backfire, but still some (but less) popping.

Popping on decell can either be rich or lean, the symptoms you have is most likely an OVER RICH air fuel ratio.

WHY?
**In hot weather the air fuel ratio will tend to run RICH and you state a significant "popping" and loud backfire happens, this is the raw fuel (too rich) burning in the pipe causing the loud backfire.
**To verify that the air fuel ratio is RICH you state that in cooler weather you get NO BACKFIRE and LESS POPPING, colder ambient temperatures will have leaner air fuel ratios thus LEANING out the air fuel ratio decreasing the problems you state.

The solution:
You can add a recalibration box that you can adjust as you ride, this way you are not stuck with waiting for the dealer to fix the problem, and you will have the ability to adjust for changing ambient conditions whenever you wish.

Other than that finding an ATV dyno and someone with the knowledge to do the work would be slim to none.
 
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