Back Firing
Tourer
Joined: Nov 2007
Posts: 285
Likes: 3
From: Parkton,MD.
Backfiring
Having gone thru this same problem with three EFI Harleys I know for a fact that decel pop can be eliminated. The 2008 Heritage that I have now has the SERT System, Rinehart Slip On's and K&N Hi Flow AC. At dealer #1 I had my bike Dyno Tuned by a Tech who was supposed to be an expert, after four test runs each time I took the bike back to the expert. He finally said that I would have to live with the decel pop. I knew that was bulls...t as I had been down the same road before with a PC, also a Rev Tech DFO on two previous Harleys. I finally decided to spend another $200 and take a chance at dealer #2. The Tech was a young guy who knew how to tune my SERT. Took bike out for test run, no backfire or decel pop. Gas mpg = 40--42 at 70mph, HP=73, TQ=87, yes I know the numbers could be a bit better but I use my bike for long distance riding and not for racing. I feel that I have a good compromise between adequate power and economy.
Intermediate
Joined: Oct 2007
Posts: 38
Likes: 0
Lets think: Poppin happens when fuel explodes outside the cylinder chamber, cause when decel some fuel escapes through exhaust valves.
Adding fuel on 0% may help cause explosion happens a little before, but when decel your bike will not reduce speed as before. (that happened to me)
If you use exhaust without baffles, exhaust gases will run free, increasing popping, so another option is to put some baffles.
Adding fuel on 0% may help cause explosion happens a little before, but when decel your bike will not reduce speed as before. (that happened to me)
If you use exhaust without baffles, exhaust gases will run free, increasing popping, so another option is to put some baffles.
Tourer
Joined: Jan 2007
Posts: 271
Likes: 0
From: Easton, PA
I had the same thing after I had the dyno - lots of popping on decel. I took it back to the dealer and they put it back on the dyno and made further adjustments. There was no additional charge since they did not get it right the first time. I still get occasional popping but only 10% of the time. They told me minimal popping is normal.
Elite HDF Member
Joined: Jan 2006
Posts: 4,357
Likes: 11
From: The Lone Star State
I had my PCIII dynoed and the popping is all but gone. it pops less than 10% of the time, and even then its mostly a muffled kinda pop, not a full backfire. I think I'm running a bit rich in some spots, but am waiting to retune until I get my new exhaust system.
Cruiser
Joined: Nov 2005
Posts: 120
Likes: 0
From: Windsor ON Canada
I have decel pop on my carbed 2002 FLHT. Had it dynoed after adding a High Flow K@N air filter and dynojet kit. I have Screaming Eagle aftermarket pipes. He did it again after having decel pop and poor gas mileage. He told me it's set up perfect. Still has the decel pop. The stealer readjusted it with little improvement. I checked the exhaust for leaks then had it rechecked again. I was told By another tuner I might need it rejetted and am waiting till spring to have it retuned. This has been a real pain and I should have had it done while I had it in for service this winter but they didn't want to tune it in cold weather. I thought it was more of a carb problem but it looks like fuel injected bikes have the same problem. I'm glad there is a fix for it after the tuner at Tough Customs blew me off as imagining it. Three years of that is enough!
Thread Starter
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Tourer
Joined: Jan 2005
Posts: 380
Likes: 0
From: San Diego
Guess I will take it back to the dyno place and see what they say. Mine even pops when I am in 6 gear and let off the throttle.
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Cruiser
Joined: Apr 2007
Posts: 106
Likes: 0
From:
I had alot of decel popping with v&h longshots & SE air cleaner. Went with PCIII & it reduced popping 95%, really reduced the engine heat also. Bike runs very well now. I'm thinking about a dyno tune this spring. No complaints with PCIII here. I tried taking the baffles out but didn't like the sound & had some popping too. I'd try some different baffles.