1997 FLHPI exhaust popping & rumble

Discussion in 'Engine, Fuel and Exhaust' started by perry, Oct 11, 2008.

  1. perry

    perry New Member

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    I am a new member and just bought a used 1997 FLHPI injected police bike with 37K miles. It already had the stage 1 air cleaner kit, K&N filter, Andrews EV-27 cam, and fairly loud mufflers installed. The bike pops and rumbles on decel. I had the 30K service done at local dealer and verify the ignition was re-flashed for the stage 1 kit.

    I checked the Champion RN12YC spark plugs (4000 miles old) before the service and they looked lean - all white on the insulators, no brown or tan color at all. The dealer said the ignition was properly re-flashed for stage 1 kit, but there is a revised re-flash available which I declined. Dealer also stated the plugs were OK but replaced them with H-D plugs anyway.

    Also experiencing poor gas mileage, estimating about 16 mpg. I am used to racing two stroke motocross bikes, not sure if I am riding this bike properly regarding rpm. Trying to ride in the 2000-4000 rpm range.

    Bike seems to run strong, does not smoke.

    My questions:
    1. Do you think the popping/rumbling is caused by the Andrews EV-27 cam and pipes ?
    2. Is popping/rumbling normal for these mods ?
    3. Would external ignition device like TFI help stop the popping ?
    4. Are all white spark plug insulators acceptable for the Evo motor?
    5. Any ideas on the poor mpg ?
    6. Who makes the H-D brand oil filter and spark plugs ?

    Regards,
    Perry
     
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Perry,

    I have a '91 Dyna. Your bike is EFI, right?

    1. Probably not.
    2. No.
    3. Might, but something else is wrong with you only getting 16 mpg. Fix that first. TFI allows you to adjust the fuel injection, not the ignition (spark).
    4. Seems too lean - which does not makes sense with the low gas mileage. I run the Champion plugs you did, and they look normal when I pull them.
    5. I suggest trying to solve the poor mpg first. Look for leaks in both the exhaust systems, and the intake. The latter you might do by spraying WD40 on the intake with the bike running and see if that affects the idle (yes is a leak). BE VERY CAREFUL. WD40 IS FLAMABLE.
    6. I don't know, but I think Glider has that info in the Tips section (see above).


    TQ
     
  3. perry

    perry New Member

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    Hi TQ,

    FALSE ALERT on the poor mpg. I panicked when the fuel light came on after 75 mile ride and was not thinking clearly. I also did not realize that I only put in 2.5 gallons, NOT 6 ! So, the fuel guage needs fix.

    I checked the new H-D plugs and they look slightly better with a couple tan spots, not completely white like the Champions.

    I am also rolling off the throttle easier which is reducing the popping. Used to chopping the throttle from my motocross racing.

    The 1997 FLHPI is fuel injected ex-police bike. Maybe the TFI unit can adjust the fuel to help the popping.

    Thanks for your response.

    Regards,
    Perry
     
  4. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    OK. Good about the fuel mileage issue, because that did not compute with the plug data. I also have a FI '03 UC. I use Champion plugs in that bike, but not the RN12YC, rather the RA8HC. See this site for selecting Champion plugs:

    ChampionSparkPlugs.com stocks every spark plug made by Champion SparkPlugs!

    From my read, the RN12YC plugs are the right ones for your bike. I use this plug in my '91 Dyna (1340 EVO).

    Check your exhaust side for leaks. Pay special attention to the "Y" crossover out of the rear head, looking for a crack in the pipe itself. You may have to remove that shield to see it.

    Check for leaks on the intake side with the WD40 test, bearing in mind the warning. Best to do that when you first start it, so that it is not TOO hot, but the pipes get hot right away (as I am sure you know).

    If you can find no leaks, try wobbling the wires to the injectors with the bike running checking for a broken wire. Glider has identified this as a problem on some bikes.

    If all that checks out good, I think the TFI route gives you a simple, USER friendly way to adjust the lean fuel issue that may be contributing to the popping, and the overly dry plugs.

    TQ
     
  5. Bill S.

    Bill S. Member

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    I have a carbureted '97 FLHR Road King with Samson slip-ons. It also rumbles and pops if I chop the throttle. Never thought anything about as I assumed it was normal. Is it not normal?
     
  6. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Check out this post:

    Carb question - Harley Davidson Community

    TQ