Strange engine sound at second startup


Viewing 15 posts - 1 through 15 (of 19 total)
  • Author
    Posts
  • #28906
    AvatarSimon Alexander
    Participant

    Hey everyone,

    I wanted to ask if it happens to others.

    When I start my bike after the night when engine is cold, it sounds very smooth, the engine is not too loud, but when I stop after a ride for a break and try to start it again, it feels that engine works very loud at the beginning for a few seconds and when I continue to ride engine seems much louder than it was the first ride. Has this happened to anyone? Is it normal?

    #29009
    Max KoolMax Kool
    Participant

    I bet you mean the cam chain rattling till the tensioner is up to pressure?

    #29011
    AvatarFreccia-nera
    Participant

    I’ve noticed some slight metallic rattling sometimes when I’m riding at a low rpm over small bumps or uneven terrain. I don’t know if it comes from the chain or the gearbox or elsewhere. It’s hard to reproduce, it just happens sometimes. Has anyone experienced a similar issue ?

    #29186
    AvatarSimon Alexander
    Participant

    Yes I think it’s chain rattling till the tensioner is up. Is this mechanical issue or normal bike behavior?

    #31211
    AvatarJohan23
    Participant

    https://youtu.be/0u0lE4hM1ok

    I have the same problem and was planning on fitting a manual timing chain tension adjuster. After removing and inspecting the hydraulic one I decided to test a slightly thicker oil instead.

    15w60 did the trick and it is now silent. I think this is due to tolerances in the making of the adjusters. Some have a slightly higher internal leaking that does not match with the thin oils that are standard.

    Check the Youtube clip for more info.

    #31474
    Max KoolMax Kool
    Participant

    Don’t install a manual cam chain tensioner.

    1. with a stroke this long the delta-length from the crankshaft to the cylinder head between a cold and a hot engine means the chain will be either too tight on a hot engine, or too loose on a cold one.

    2. the chain tensioner also dampens the little speed differences of the camshaft at low rpms, due to the valves pushing the camshaft a little forward at closing.

    15W60 is the solution according to Pirate Racing, and I believe him, he knows his stuff.

    #31565
    AvatarKev212
    Participant

    Install the Ktm dirt tricks camchain tensioner and all your problems will be gone

    #33187
    AvatarCycledino
    Participant

    Which Ktm dirt tricks cam chain tensioner model and have you done this on yours?

    #33188
    AvatarJohan23
    Participant

    <p style=”text-align: left;”>Don’t install a dirt tricks tensioner on a 701. It will remove the sound. But it will also put too much stress on the timing chain and bearings. Will be an very expensive service later in.</p>
    Change to a bit thicker oil and you are good.

    #33189
    Avatarhannesd
    Participant

    are we talking about the 701 or 401 engine?
    i’ll be changing the oil soon on my 401 and was planning on just putting 10w40 semi synth oil in?

     

    #33191
    AvatarCycledino
    Participant

    I was asking about my 701. I will try the heavier oil. Thanks for the info, you saved me $100!

    #33199
    VanessaVanessa
    Participant

    @hannesd why not use the recommended 15W50? I’d only switch to a 10W oil if I lived in an extremely cold climate. And then only in the winter. And a 40 grade oil will most likely be too thin when the engine gets hot. A 10W50 would be a good cold climate oil for the 401.

    #33206
    Avatarhannesd
    Participant

    because the 10w40 is more common and therefor cheaper then the 15w50.

    if this would do no harm, then i don’t see the benefit of the more expensive oil.

    i have always used 10w40 in all my previous (street-) bikes.

    only my husqvarna FC 250 dirtbike gets the 15w50 oils since this engine is on constant load and higher revs on the track.

    • This reply was modified 2 months, 3 weeks ago by Avatarhannesd.
    #33209
    VanessaVanessa
    Participant

    Okay. Speaking personally, engine oil isn’t something I want to cheapen out on. But if you decide to try it, let us know if there are any damaging effects on your engine.

    #33210
    VanessaVanessa
    Participant

    My local Husqvarna dealer CPS Motorcycles of Hinckley mentioned to me that oil quality and grade were important on the 401 singles, and they certainly didn’t recommend cheap oil. They also said that main engine bearing pick up was not unheard of on these engines, which was especially important as Husqvarna don’t offer main bearing shells as spare parts for these particular engines. These were the exact words of the dealer.

Viewing 15 posts - 1 through 15 (of 19 total)
  • You must be logged in to reply to this topic.