Motorcycle Club » Star 1100 Classic & Custom

popping on deceleration

48 posts from 16 voices
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  1. wzdartan

    afr = air to fuel ratio. That should tell you if you're running too rich or lean. Did you write that you are running stock jets? Here is some info I found regarding jetting setups for a Hypercharger
    Stock exhaust...
    1.2 air bleeds
    1 shim added to needle
    122.5 main jet frt.
    120 main jet rr.
    2 turns out from lightly seated pms

    Performance exhaust...
    1.2 air bleeds
    1 shim added to needle
    125 main jet frt.
    120 main jet rr.
    2 turns out from lightly seated pms
    I read that some tuners recomend leaving the air bleeds stock irregardless of what Kuryakyn recomends. They say changing them makes the carbs. difficult to tune.

  2. wzdartemon

    Thanks Dan,will need to further investigate the jets and get back.Thanks

  3. wzdartemon

    No more backfiring on decel since upgrading to Maxair predator pro.Success finally and performs a lot better than the hypercharger,left the hypercharger on for appearances only.
    Only 1 little issue left is that it backfires a little at idle,
    142.5 R/145 F jets
    22.5 pilots
    3.25 turns PMS
    2nd clip from top on needle
    no shims
    14mm float level.
    Suggestions please

  4. earnmanfan960

    don't know if this will help anyone but i had bad exhaust popping on deceleration and my dealership asked if i had treated gas or emptied carbs the previous fall and upon telling them i hadn't they suggested cleaning out carbs in which i let them do and the result was NO MORE POPPING (now i treat gasoline and turn off supply emptying carbs going into winter)

  5. LiddleBen

    I have the same pipe and I run a .127 front main and a .130 in the rear carb. I have no backfire. I donot want to get into the whole Jetting thing again here. I will say that I run a really open air setup.;Thunder charger brand breather. I agree with Dan the bike seems to be running lean. I would try to find someone who knows carbs and have the jets changed and the needles reshimmed. then do a tune and sync. Just remember what works on one motor will not nesecarily be ideal for another. all motors even the same model are each unique. Good Luck.,LiddleBen

  6. wzdartemon

    Finally no backfire on idle or decel after installing Maxair predadator pro,Problem at idle was carbs not synced properly.
    After being dyno tune twice have i been ripped off.Carbs were out of sync.
    Used the yard stick method to find that the font carb was unable to be synced.This would have been from factory and even the mechanic I had been taking it to asured me they had been synced.......
    Well I learnt a valuable lesson is that you dont trust so called experts.
    I found the reason why it could not be synced on the carbs is that the linkage at the carb sync screw was out by 1mm .This would not allow me to adjust the screw at the carb sync to beyond its maximum point.Back carb would always pull more vac.
    So to fix this I cut the spring tensioner between the two linkages at the carb sync screw adjuster by 1 turn on the spring and perfecto I could sync both carbs.
    Didnt cut the spring at the carb screw but the spring inbetween the two lingage arms.
    Purrs like a Kitten on steriods now.....
    I do reccomend the maxair kit and also following instructions to the letter and you"ll be sweet.
    But the most valuable lesson learnt is not to trust m/c mechanics as ive waisted a lot of $$$$ on there services that they F##k up.
    If it wasnt for the help on these forums I would be down to square one with no little difference..

  7. tunc

    glad you got it sorted out
    hard to get a good mechanic and when ya find one they dissappear

  8. TRaiterJohn

    Ethanol is being added to gas as a substitute for methyl -tert-butyl ether (MTBE). MTBE was added to gas to oxygenate it. That raises the octane number and improves combustion (environmental concerns). Unfortunately, MTBE created its own environmental concerns.

    Ethanol is the most-available, relatively low cost substitute for MTBE. Besides it is green, renewable energy, and it creates a market for corn, and all sorts of politically correct things. Who cares if it is any good for what we put it in...

    Sorry, I'll get off my soapbox now. Don't ask me about this. You don't want me to get started...really.



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