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Since Install Nothing but Grief!

Discussion in 'CV Performance' started by johnr733, Aug 17, 2011.

  1. johnr733

    johnr733 New Member

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    Since installing this kit I've been unable to tune the bike to good running condition. There always seems to be some issue. First I thought it was set properly then I realized I had no acceleration after about 60mph. So i tweaked the mixture screw leaner (tighter), and I had better acceleration up top, but it started backfiring and missing trying to climb a hill. So I disassembed it, rechecked everything, reassembled it and went riding. It wasn't that pleasant a ride (didn't feel as smooth) but t was ok. Temperature started to increase quite a bit, 94 in Denver is kind of hot. Had a nice open stretch of road so I grabbed a handful of throttle and boom! Backfires and complete loss of accelertation.

    The thunderslide was nowhere this hard to tune.


    1997 FLHR bore to 88", ported, polished, SE air cleaner, hooker slip-ons. 45/190 in the carb.
    johnr733, Aug 17, 2011
    #1
  3. cowboy

    cowboy Moderator Staff Member

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    John welcome to the site , I'am sea level so setting up to mile high i' sm off a bit but we do have a few who do live up your way for the jet size but it sounds like you might have a air leak
    cowboy, Aug 17, 2011
    #2
  4. HarleysLR

    HarleysLR Active Member

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    You're to lean on the slow jet, good on the main. I live in Colorado Springs which is higher than Denver and I've been running CV Performance stuff for years in built and stock Evo's and TC's 88's & 95's and I use the same jet in all of them a 48 slow and a 190 main. There could be an air leak, I know everone says use propane torch unlit or wd 40 but for me nothing beats carb cleaner for finding even the smallest air leak. Good luck, and don't try and miss and match thunderjet stuff with cv performance stuff they are not compatible.
    HarleysLR, Aug 17, 2011
    #3
  5. kenfuzed

    kenfuzed Administrator Staff Member

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    A #45 pilot jet is too small for an 88", typically a #46 or #48 is recommended for that size engine regardless of altitude.

    As mentioned it is imperative that DynoJet parts not be combined with CVP or even OEM parts, though CVP parts will work with OEM. The DynoJet and Thunderslide kits included 3 components that must be removed and while I see you mentioned that the slide was replaced it is worth mentioning again that the needle AND emulsion tube made by DynoJet will not work with any other brand or OEM part. Combining the CVP needle or an OEM needle with a DJ emulsion tube can throw off any chance of a reasonable tune. Also when replacing the emulsion tube with either stock or CVP the needle jet (stainless steel nozzle) must be replaced and oriented in the correct direction. It is common for this part to fall out or be reinstalled upside down.
    [​IMG]
    [​IMG]

    Vacuum leaks are the most common cause of performance issues following any work on the intake system but it doesn't hurt to check what components are installed for good measure.

    HTH
    kenfuzed, Aug 18, 2011
    #4
  6. johnr733

    johnr733 New Member

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    Ok vacuum leaks. Do you agree that there are only three logical places this type if leak can occur? 1. the seal at the cylinder head intake 2. the seal at the carb to the intake and 3. the rubber tube on the VOES to the carb.

    Any other leak shpuld also be leaking oil (i.e. breather bolts, rocker covers), right?
    johnr733, Aug 18, 2011
    #5
  7. HarleysLR

    HarleysLR Active Member

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    and exhaust at heads, yes that's about it.
    I'd try the slow jet,
    HarleysLR, Aug 18, 2011
    #6
  8. johnr733

    johnr733 New Member

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    johnr733, Aug 18, 2011
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  9. cowboy

    cowboy Moderator Staff Member

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    When UPI back off the throttle it can suck cold air & cause the popping
    cowboy, Aug 18, 2011
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  10. JohnnyBiker

    JohnnyBiker Well-Known Member

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    JohnnyBiker, Aug 18, 2011
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  11. johnr733

    johnr733 New Member

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    johnr733, Aug 19, 2011
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  12. cowboy

    cowboy Moderator Staff Member

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    Sounds like you found your leak
    cowboy, Aug 19, 2011
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  13. kenfuzed

    kenfuzed Administrator Staff Member

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    Re: Exhaust leak

    I would recommend brand new seals, preferably the Screamin Eagle seals which in my experience seal better. Exhaust seals crush in order to form a seal, so removing and reinstalling often leads to leaks. Any time I pull pipes even to get at something else I replace these seals. Especially in your case where the head to pipe angle might be slightly off. If the angle is too drastic you may need to have a muffler shop help you bend the pipe ends to achieve a more flush mating.
    kenfuzed, Aug 19, 2011
    #12
  14. JohnnyBiker

    JohnnyBiker Well-Known Member

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    Re: Exhaust leak


    I SECOND THIS! I used to have those crush gaskets and they are the junkiest things in the world. I like the SE gaskets as well.
    JohnnyBiker, Aug 19, 2011
    #13

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