High pitched squealing noise.

Discussion in 'General Questions' started by James L, Jul 15, 2016.

  1. James L

    James L Member

    I have got a high pitched squealing noise coming from my 80cc motor all of a sudden.

    I cannot pinpoint the exact location other then it's coming from the motor. Being partially deaf doesn't help lol.

    It just started this tonight after a one mile ride. Almost like a high pitched whistling noise.

    It's not as loud while idling but is pretty loud at full throttle. The engine runs fine as I figured why not ride it like usual WOT lol.

    I ride it everyday and have been riding it back and forth to work.
    About 20 miles round trip.

    I think I have had this issue before and it went away on its own. Am i just being paranoid?

  2. Frankfort MB's

    Frankfort MB's Well-Known Member

    Either clutch is slipping, head gasket is leaking, exhaust gasket is leaking, or base gasket.....

    I would try a soapy water spray around those gaskets and if you see bubbles, then you have a bad gasket somewhere

    If that doesn't work your clutch probably needs cleaning or adjusting.
  3. crassius

    crassius Well-Known Member

    a large glob of heavy grease should be applied to the bucking bar once a month or so (I like to pull bar out, put grease in hole and push bar back in, then pack the hole in that cover well too) - a small dab of heavy grease (about the size of a peanut) between the large & small drive gears is needed about every three months (take out spark plug and slowly roll bike to turn the gears and spread that grease evenly around them)

    if that doesn't quiet the noise, look for oil residue around the gaskets
    Frankfort MB's likes this.
  4. James L

    James L Member

    Update: the head gasket is blown. Luckily I don't have to order one. There is a guy 2 miles from here that keeps parts in stock. I noticed air blowing on my pant leg and looked and there was a corner of the gasket missing.
  5. Frankfort MB's

    Frankfort MB's Well-Known Member

    That's good news (bad news you have to fix it but better that you know what it is lol)
  6. bakaneko

    bakaneko Active Member

    the stock gasket is horrible. i hope the guy you buy it from has a better quality gasket.
  7. crassius

    crassius Well-Known Member

    standard gaskets are fine - letting head get loose will burn thru any gasket
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  8. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Idk but it's been mentioned a few times by "real" motorcycle mechanics that the copper head gasket is the proper way to prevent the head loosening up and needing to be retorqued.
  9. Steve Best

    Steve Best Well-Known Member

    Stock aluminum worked OK, even reused them a few times before over sqished.
    I am now just using Headsmess's twisted teflon headgasket with wonderful results.
    Make allowances for squish gap.

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  10. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    How do you know how thick the twisted up Teflon tape will be once torqued down? I have read about it but it is not really obvious how to get it to make a nice neat circle without bulging over the cylinder or conversely leaving a crevice. A gasket at least comes with a circular hole in it.
  11. Steve Best

    Steve Best Well-Known Member

    Thin smear of any kind of thick tacky grease around the cylinder bore.
    Lay the twisted teflon around the bore, touch it into the grease, it will stick.
    Touch the edge of the bore to push the twisted teflon rope into a smooth circle about 1mm from the bore.
    Overlap on either side of any stud.
    Slide the head on and torque on evenly.
    Slip a length of solder into the plug hole and measure squish gap over the wristpin.

    The teflon squishes very flat, less than 0.005" so variation is not a huge problem.
    If any squishes into the cylinder (it has), it is not a problem.

    FurryOnTheInside likes this.
  12. crassius

    crassius Well-Known Member

    'real' motorcycle mechanics don't have to deal with bolts & studs made of chinese steel that stretch horribly over time
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  13. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Good point, even the best head gasket material can't help if still using studs made of chewing gum and not locktited in. The newbie threads make it pretty clear that replacing the hardware is one of the first things to do to ensure a good motoredbiking experience. Luckily they can be made or bought. Sick Bike Parts sell decent head studs for $10 and another $10 for the rest of the studs and bolts.
  14. Frankfort MB's

    Frankfort MB's Well-Known Member

    My grubee had excellent bolt quality. My front studs were actually 1/2in (or 12mm?) compared to the regular 10mm and were grade 5 studs I'm pretty sure

    (I haven't fooled with my MB in over a month now so starting to forget things.... Trying to give accurate guestaments till I get time for my baby;))
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  15. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    I imagine those dimensions are way off but the point that newer Grubee bolts are good quality and needn't be replaced is good info. :)
  16. Frankfort MB's

    Frankfort MB's Well-Known Member

    I know it's a 1/2 or 9/16 because it has the wide mount
    They are very thick studs lol

    Attached Files:

  17. Steve Best

    Steve Best Well-Known Member

    Frank, studs and bolts and nuts are measured by the diameter of the thread, not the wrench that goes on the nut or bolt head.
    So your head bolts do take a 9/16" or 14mm wrench on the nut, but the studs are only 8mm in diameter.
    The front studs were 6mm on older engines, taking a 10mm wrench as you alluded to, and now are 8mm and take a 12, 13 or 1/2" wrench.

    Confusing? You should try working on old British stuff...

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