Cam Chain Tensioner?

Discussion in 'Motorbike Technical Discussion' started by Si_R6, Feb 22, 2007.

  1. Si_R6

    Si_R6 Guest

    Hello to All

    I bought an R6 on a 53 plate about 6 weeks ago, lovely condition, lo
    milage etc....It was sold with a 2 month warrantee...I am not
    particularly experienced rider but I have noticed a tinkling sound o
    the over-run and I am worried it could be something like the Cam chai
    tensioners. If this is the case I need to act quickly to have i
    repaired under the warrantee. Any advice / oppinions would be mos


    Si_R6, Feb 22, 2007
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  2. My crystal ball is in the shop for repairs, and I cannot guess what
    year R6 you own, whether it has fuel injector or carburettors....
    Warranty, not warrantee. The person who purchases an item with a
    warranty is the warrantee. The seller sold the motorcycle, he didn't
    sell you.
    You would hear a loose cam chain making a lot of noise when you first
    start the engine. It would growl when cold.

    Then, once the engine was warmed up, you might hear the cam chain

    There isn't anything inside the automatic cam chain tensioner except a
    serrated plunger, a pawl, and a spring.

    The plunger pushes against a plastic rubbing block and that takes the
    slack out of the rear side of the chain.

    The spinning crankshaft takes the slack out of the front side of the

    If you think the chain is loose, it's a simple job to remove the cap
    from the end of the tensioner body and reach inside with a phillips
    screwdriver and gently push on the plunger until you hear the ratchet
    click once.

    If it clicks twice, the spring loaded was stuck for a long time.

    But your description of a "tinkling sound" on the over run leads me to
    believe you either have loose valves that need to be re-shimmed, or
    the fuel air mixture is too lean when you roll off the throttle.

    If you pull out the spark plugs and look at the insulator inside, tiny
    little black specks that look like pepper indicate that the cylinders
    are pre-igniting, i.e., the cylinders are firing *before* the spark
    jumps the gap.

    The little black specks are a motorcycle speed tuner's
    warning that the fuel air mixture is verging on unsafely lean.

    The next step is little silver balls of melted aluminum on the spark
    plugs, meaning the pistons are melting.

    Carburettors that are all plugged up with gum and varnish will cause
    an engine to run lean and ping.

    Fuel injected engines with plugged up fuel filters will run lean and
    FI systems often have silly gadgets like hot oxygen sensors in the
    exhaust system and other sensors that tell the ECU what to do and when
    to richen the mixture.

    Then there is the business about the "53 plate". I suppose you have a
    reduced horsepower output engine that may may have a restrictor in the
    induction system that keeps it from breathing enough air to achieve
    the full horsepower of the design.

    You may also have an air induction system that injects extra air into
    the exhaust to complete burning. Excess air might be heating the
    exhaust pipes and making them expand rapidly.

    It's even possible that there's a loose exhaust fitting on the
    cylinder head that's allowing an air leak.

    Engines which are running too hot because of advanced ignition timing,
    lean mixtures, or wrong heat range spark plugs will make a groaning
    sound when they are operated in the mid-range, even though they make
    beautiful music at high RPM when they are running full rich.
    Potage St. Germaine, Feb 22, 2007
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  3. Si_R6

    Si_R6 Guest

    Wow Thanks for the reply and the english lesson :0)

    I am from the UK so the reference to the "53 plate" is indicitive o
    the year of registration...53 shows that the bike was registered durin
    the second period of my case the bike is feu
    injected and not restricted...also I have a scorpion end can...I hav
    noticed that some of the gases seem to escape before they reach the en
    pipe...Sounds like a quick trip to the local service center is i
    order...As you suggested I will check the plugs and the chain etc....

    Once again thanks for taking the time to reply...


    Si_R6, Feb 23, 2007
  4. Aftermarket canisters are generally for style, or are installed as a
    replacement part for a scraped original equipment part. They do
    nothing for horsepower, except possibly hurt the midrange power.

    A canister with less restriction doesn't trap the heat in the exhaust
    system, and that changes the speed of the acoustic waves flowing
    through the exhaust gasses. This changes the timing of exhaust pulses
    returning to the cylinder during the valve overlap period when both
    valves are open.

    Yamaha is quite aware of the phenomenon of reverse airflow through the
    open exhaust valve and out the open intake valve into the intake tract
    and through the carburetor.

    A carburetor is a dumb device that doesn't know which way the air is
    flowing, so it picks up an extra
    shot of gasoline when the air is flowing backwards, and another shot
    of gasoline when the air is flowing the right direction.

    The extra fuel in the mixture cools down the combustion process,
    aggravating the acoustic tuning problem.

    Yamaha invented the Exhaust Ultimate Power Valve (ExUP) about 1989 and
    offered it on FZR-1000's and FZR-750's, but the YZF-R6 didn't get ExUP
    until about 2006 or 2007.

    It's a computer-controlled servo-operated exhaust throttling valve
    that breaks up adverse pressure waves that cause reverse flow during
    the camshaft overlap period.

    Fuel injected motorcycles don't have the problem with getting an extra
    shot of fuel, the ECU tells the injectors to open wide for a
    prescribed number of milliseconds, according to the map program in the

    But exhaust throttling still helps eliminate the flat spot in the
    midrange. All of the Japanese 1000 cc sportbikes have their version of
    ExUP nowadays.

    If you want a few more horsepower and a little better midrange power,
    you can install a Power Commander and re-program the fuel and ignition
    timing map.
    If you have found a tiny hole on the underside of the exhaust system
    at the low point, it's there to allow condensation to drip out of the

    Don't do anything to seal up that hole. Yamaha exhaust systems are
    incredibly expen$ive.
    Potage St. Germaine, Feb 23, 2007

  5. Actually, there are some bikes that benefit immensely from a simple can
    change. The old Suzuki 1200 Bandit was one.

    Ducati used to ship their 916/996 bikes with 'aftermarket' cans in the
    crate! The ones fitted were simply there to bring the thing within noise
    limits. Not sure if they do this with the new bikes, mind.

    Some bikes are genuinely strangled by their cans, for noise purposes.
    That said, most riders change theirs for style, as you say.
    The Older Gentleman, Feb 24, 2007
  6. And my GSXR-750 came with what looked like a huge 6-inch diameter
    muffler that should have been free-flowing and quiet at the same time.
    But the back side of the muffler was flat and the internal volume of
    the muffler was only half of what it appeared to be.

    It strangled horsepower output and the next generation GSXR's had two
    mufflers, one on each side and riders would drag the lefthand muffler
    until they learned to jack the rear end up with ride height

    It made the motorcycle look like a stinkbug running down the road, but
    jacking the rear end up was something that racers were going to do
    Now I have a Yoshimura competition only exhaust system and canister.
    But I cannot ride the GSXR
    out of my driveway, the neighbors will complain and the property
    owners association will demand that all
    motorcycles be forbidden from entering the gate.

    They can't do anything directly about sportriders with loud pipes drag
    racing the highway, but I can't even get to the highway without going
    over a hill and making the neighbors angry.

    They already put a stop to the private motocross track on a rancher's
    adjacent property.
    Yes, riders with lots of money are willing to spend it on exotic
    materials and surface finishes, and they think theyshould also get a
    little extra power thrown into the deal.
    Potage St. Germaine, Feb 24, 2007
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