Having an issue with my Motorcycle

Discussion in 'Motorcycles' started by ionstriker, Apr 25, 2019.

  1. ionstriker

    ionstriker

    Messages:
    331
    I'm not really sure under which sub forum this goes, but I'll just post it here.

    Hey all, so I have a dominar 400 motorcycle. It's pretty new, I got it last year September and it's run around 5.6k Kms. So I have been noticing an issue where if I give more than 50-60 percent throttle I hear a mechanical noise in the engine, similar to the noise you get when you try to accelerate from a low speed on a higher gear, the gearbox noise, but not as loud or intense. It sounds similar to engine knocking. But what I don't understand is, why this noise is present even in higher rpms. It is only present at a certain rpm range when the above mentioned percent of throttle is applied and then the noise goes away. I don't have any issues post 100kmph all the way till the top speed. Any idea if this is an issue?
     
    Last edited: Apr 25, 2019
  2. Vegard

    Vegard

    Messages:
    2,889
    Location:
    Norway
    The Motorcycle sub forum can be found here.

    Could you give a more detailed description of the sound? Is it a metallic sound, a throaty induction sound, does it rattle etc etc.
     
  3. ionstriker

    ionstriker

    Messages:
    331
    Ah I see. Didn't think to look there. I guess the moderators can move this there.
    You know the sound you get when in a higher gear and you try to accelerate hard? That banging noise from the transmission? Well it's very very similar to that except its not at the same level or magnitude. It's like a small metallic ball is being thrown around inside the engine.
     
  4. Vegard

    Vegard

    Messages:
    2,889
    Location:
    Norway
    Did it start suddenly or gradually? Is it getting worse? Is the sound accompanied by vibrations?

    Could it be as simple as your chain slacking?

    I'd recommend having a professional take a look at it.
     
    Last edited: Apr 25, 2019
  5. ionstriker

    ionstriker

    Messages:
    331
    I
    It doesn't seem to be getting worse. It doesn't always happen but it most of the times it does. It started suddenly. I was riding with a pillion and was on 3rd gear. I gave around 60 percent throttle and instantly I heard a metallic thud and the engine almost seized. I think since then I have been hearing this noise on and off. But last month I went on a 400km tour and didn't hear the noise at all on the highways, no matter how much throttle I gave. But I did lube the chain well before the journey.
    And not exactly sure how chain slacking noise is.
     
  6. Vegard

    Vegard

    Messages:
    2,889
    Location:
    Norway
    It think your chain slider may have come off.

    This video may be helpful
     
  7. W3HS

    W3HS Premium

    Messages:
    25,958
    Location:
    Thailand
    Sounds a lot like chain slap to me. Irritating but not disastrous. Although that shouldn’t cause an interference with the engine (or drive sprocket from the gearbox) unless you’ve got a seriously worn chain and/ or sprocket, in which case it could jump and get caught.

    Check your chain for slack, shouldn’t have more than an inch up or down as a rule of thumb.

    The annoyance with chain slap is that it can occur at certain rpm or speeds and be fine otherwise.

    This occurs around the time that you’ve mentioned as the chain stretches slightly from new. Loosening up the back wheel and winding out the horizontal tensioners should take up the slack, alternatively invest in spring tensioner, similar to what a derailleur does on a bicycle, and that should eradicate the noise.

    I can’t tell you how many frustrating hours I’ve spent trying to chase a noise only for it to be the chain. Now it’s the first thing I check when a noise appears.

    Also, don’t forget to clean and lube. WD40 is the simplest, cheapest option but there are proper products available if you want to spend the money.
     
    Vegard likes this.
  8. ionstriker

    ionstriker

    Messages:
    331
    I have been having a few chain noise issues for every 400-500kms which go away after I lube them. This definitely sounds different. Although I will check the chain slider as well.
    Also just to mention, there are more chances of getting this noise while riding on a mild inclination. So lets say I'm doing 35kmph on 3rd gear, and open up the throttle 100percent, I can hear a knocking sound for a few seconds and then disappears.
     
  9. W3HS

    W3HS Premium

    Messages:
    25,958
    Location:
    Thailand
    There are so many reasons you could get a knock which makes finding them a royal pain.

    It could be anything from a loose fitting - I’ve had engine guards rattle loose and drive me nuts, to something deeper like valve clearance incorrect which could cause an engine knock. Fuel knocks (detonation) can occur when mixtures are off but the fuel injection system usually adjusts that, assuming you have FI as almost all modern bikes do.

    If you can’t solve the problem then pop into your local mechanic and describe what you are experiencing and they can do so expert digging to find the knock.
     
  10. wfooshee

    wfooshee Premium

    Messages:
    4,363
    WD40 is not a lube, it's a cleaner. its effect will be short-lived, as when it evaporates, you have dry, unlubricated surfaces. Get a specific chain lube spray.

    As for the noise, I don't know anything about that bike, but are the cams chain-driven? You may have an issue with timing chains, specifically tensioning. I know that the FJR had an issue with the timing chain tensioner in early years that would allow the chain to go slack, and the sound was described a marbles in a can. With the FJR, and most bikes, cam timing going bad can destroy the engine, as the valves and pistons will try to overlap each other. THAT is a noise you don't want to hear!
     
    Last edited: Apr 25, 2019