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Thread: nasty engine noise

  1. #1
    Join Date
    Jun 2004
    Location
    lemoore CA
    Posts
    24

    Question nasty engine noise

    started hearing a loud knock only when I let it idle then pop the throttle, also when I am in 4th and 5th gear about 3/4 throttle the same noise but like a rattle. I have a curtis sparks header and pipe.

    No jet kit or intake


    need some help with this situation.

  2. #2
    Join Date
    Dec 2003
    Location
    Lynchburg VA
    Posts
    74
    could b wrist pin needle bearings r gone
    04 Raptor..dynojet jet kit, shortened white brothers r-4, white brothers airfilter, holeshot xcr's, holeshot mxr's on douglas rims, ac grab bar and more torque u can shake a stick at..oh yeah, blaster front shox for drag racin

  3. #3
    Join Date
    Apr 2004
    Location
    Portland, CT
    Posts
    82
    Check for low oil, loose motor mounts, and loose bolts before assuming its anything internal. Once you know nothing is broken or loose outside, then think internals. I know my 2002 Mojave 250 knocked like crazy when it was under a load (lugging it) but everyone said it was normal for those machines. It still scared me though. The Suzuki/Kawi seems to be a more updated version of the old twin cam Mojave 250 motor. If so, that knock (piston slap maybe?) might be ok. I know the higher compression on the Mojave was supposed to be part of the reason why it made so much noise. Regardless, check compression next. Unless you are dead set on ripping it apart...you might be better off doing some inexpensive testing first.
    "He who dies with the most toys, wins"

  4. #4
    Join Date
    Mar 2004
    Location
    florence,south carolina
    Posts
    43
    sounds like your cam chain maybe stretched & no more auto- adjust left on the tensioner.
    yfz450 #310

  5. #5
    Join Date
    Mar 2004
    Location
    florence,south carolina
    Posts
    43
    what you are hearing is the loose chain at idle slapping around. when you rev it inertia makes the chain balance and the slack is equal around the chain in the motor.def need to get it checked,if it jumps a tooth,lots of problems.
    yfz450 #310

  6. #6
    Join Date
    Jun 2004
    Location
    louisiana
    Posts
    349
    it might be the valves, but you need to jet it
    450R
    kenda fronts
    mxr rears
    ac nerfs

  7. #7
    Join Date
    Jun 2004
    Location
    louisiana
    Posts
    349
    it might be the valves, but you need to jet it
    450R
    kenda fronts
    mxr rears
    ac nerfs

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