death rattle? - with video

Discussion in '2-Stroke Engines' started by kallsop, Jul 3, 2009.

  1. kallsop

    kallsop Member

    Here's the story. The guts fell out of the original muffler and I rode the bike home, only a mile or so. All was fine, the engine had monster power then but also really noisy. I didn't abuse it and kept the revs low.

    My son took out the bike without telling me, and he says he ran it for 10 minutes and didn't notice anything. I wonder about that!

    Now I put on a replacement muffler. The muffler is super quiet, it has the welded end, but also is a power killer for sure. That's not the immediate problem though. Now the engine has a terrible rattle. Take a listen:

    death rattle?

    It sounds very bad and there's a lot more smoke than before. The clanging noise seems to be coming from the crank/clutch area. Before I start disassembling things, any thoughts on what I'm going to find?

  2. arceeguy

    arceeguy Active Member

    The clutch design in these engines is inherently noisy, it is due to the clearance between the carbide ball bearings and the ring gear. They make the most racket when disengaged, but the metallic rattling will stop once the clutch is engaged.
    Last edited: Jul 3, 2009
  3. Hawaii_Ed

    Hawaii_Ed Member

    It just did not sound that bad to me, I dunno. How does it ride?
  4. pdxrhett

    pdxrhett Member

    that chain seems to be hopping a lot for the clutch to be all the way in - maybe it is grabbing only a very tiny bit? try adjusting your clutch
  5. kallsop

    kallsop Member

    OK, so maybe it's just the clutch, but the noise is louder than it was before putting the new muffler on. Maybe I need to adjust the star nut and it's a coincidence that it got noisier the same time as the muffler escapade? I noticed the clutch might be grabbing very very slightly and will adjust that out. It doesn't show in the video, but the exhaust gasket is leaking now too.

    BTW - I tried searching for a thread on how to get more power out of these welded end cap mufflers and came up empty. Anyone can recommend a good thread? First thought is to use a dremel to cut across the weld and pop off the end cap to see what's going on in there. The original muffler end cap was held on by two sets of nut and bolt, and had very noticeably more power, like 50% more.
  6. Mountainman

    Mountainman Active Member

    not sure why -- because I don't see anyTHING

    but it sounds like an exhast leak ??

  7. biken stins

    biken stins Member

    Tie a rope on the kid and drag him untill he tells you what really happen.
    Make it look like a accident.
    Just kidding of course.
  8. linnix13

    linnix13 Member

    if you want more power then drill a 1/4" hole on the bottom of the baffle next to the original hole, the bigger the hole the more power but also the more sound, 1/4" is perfect for not being to much louder but alot more power
  9. thescooterguy

    thescooterguy Member

    i agree . i think the clutch is partially engaged , if you watch the chain and listen to the rattle you can see they have a rhythm . its probably worse now with the new pipe due to ,more power , that's my best guess.
  10. Nitropeewee

    Nitropeewee Member

    ferget the can type muf go wit an expantion chamber youll never look back! louder but wroth it. mine came off a china type 50 cc four wheeler.
  11. radrob

    radrob Member

    dosent sound to bad to me.
    the chain is moving around when you rev it up. clutch??
    i am still new.
  12. HoughMade

    HoughMade Guest

    Here's a thought- if the new muffler is quieter, maybe you just hear the rattle more now.
  13. arceeguy

    arceeguy Active Member

    That makes total sense.
  14. it shouldnt smoke like that and mine doesnt smoke or sound like that.
    you either have too much or not enough oil in the gas and your chain looks loose.
    and you revving it like that is making it worst.
  15. Fabian

    Fabian Well-Known Member

    Sounds exactly like my engine that blew a bottom end conrod bearing.

    Buy a new engine as it's not worth repairing it - keep the revs low and use 20:1 oil and fuel ratio
  16. kallsop

    kallsop Member

    That video was about 20 hours runtime ago and it's still running. After tightening all the bolts and adjusting the chain, no more noise.