Discussion in 'General Questions' started by 1max, Sep 1, 2014.

  1. 1max

    1max Member

    my bike is acting weird I pop the chain last week and I've been getting a rubbing inside the drive holding the bike back and I'm getting a squealing inside the motor it's not real loud but its there anyone have any ideas?

  2. dirtwarrior

    dirtwarrior Member

    Sounds like the sprocket is out of line. I am no expert though
  3. HeadSmess

    HeadSmess Well-Known Member

    pop the covers. any rub marks on the inside of the cases is obviously something rubbing. if so, fix it ;) last time i ignored that sort of squeal, my crank nut leapt out through the cover!

    you may have the wrong size chain, ie, its too wide if its rubbing the case behind the sprocket.

    this may sound stupid, but are you running oil? could be an imminent seizure...
  4. crassius

    crassius Well-Known Member

    I've seen a lot of cheap drive sprockets being delivered. They are machine stamped, and have very flat topped teeth that can lift the rollers up over the sprocket rather than letting them fit down in the troughs. Take out the plug & open the cover and watch the chain as you roll the bike. If it tries to ride up over the sprocket, then grind or file the teeth to take the edges off and make them pointier until the chain runs more freely.
  5. 1max

    1max Member

    it's a GT 2B 2 stroker I run 16 :1 synthetic 2 stroke oil in it and I get a lot of black s*** on my spark plug I took the clutch plate cover off and there is a small mark on the inside the cover from the gear my rear sprocket has been like a little out of line but its been like that the whole time and no problems before and I have an oversized number 41 chain on a bike but it's been running like that for a month and no problems before
  6. Fabian

    Fabian Well-Known Member

    16:1 oil/fuel ratio is excessive. You can safely alter the ratio to 25:1 which will cover all riding conditions.
  7. 1max

    1max Member

    I did the 16 to 1 because I'm a newbie and I seen a couple other people were doing 16 to1.but I'll try that 25: 1 Fabian thanks :)
  8. HeadSmess

    HeadSmess Well-Known Member

    i run 50:1, havent had any oil related issues since i got my first china girl over 5 years ago...

    erm. back to the issue... which gear? the big one or the lil one? ive found a few covers that had doubled gaskets that, after removing one spare gasket, turned out to need that gasket there to stop the rubbing. i call it "chinametrics" where close enough is good enough :)

    if its just the case of no space in there, try a washer between the case and cover, get another gasket, or just live with it until its worn its own clearance in.

    just look carefully and make sure its not something critical about to fall apart, such as the bearings that hold the clutch/sprocket shaft in place, or a missing nut on either the clutch or sprocket. minor disassembly may be necessary! (ie, take the clutch plate off and check under there...)
  9. Fabian

    Fabian Well-Known Member

    When running leaner than 25:1 on the oil/fuel ratio, cylinder bore wear is increased.

    I have tried 35:1 and over a distance of 4,000 kilometers (2,500 miles) the increased bore wear was significant,compared to 25:1

    50:1 isn't even a consideration "for me".
  10. HeadSmess

    HeadSmess Well-Known Member

    your internal micrometers must read to another decimal place past mine cus i havent been able to measure any appreciable wear down to 0.01 of a mm... rings yes. hard chromed bore? no.

    they flake, they chip, they get gouged when a ring breaks...but wear? where?

    get a new airfilter ;) sounds like you need one ;)
  11. Fabian

    Fabian Well-Known Member

    After 4,000 kilometers, the hard chrome had largely worn off the very top section of the bore, with the rings mostly running on aluminium.

    When i switched to 35:1 the rings had well and truly cut into the aluminium, leaving a small lip - a massive difference in wear.

    50:1 would not be a sensible option.