Loud screach upon engine braking.

Discussion in '2-Stroke Engines' started by Hello Moto!, Apr 23, 2016.

  1. Hello Moto!

    Hello Moto! Active Member

    So I threw a brand new motor on my bike just for the hell of it and something is goin on with it. I get a pretty loud screach internally in the motor when I pull in the clutch to brake. It seems worse at higher speeds.

    I think it might be the clutch but I'm not sure what to look for. What would be causing it to screach sounding like metal on metal. I know its not my chain. Seems to run fine just the loud screach lol.

    Any ideas?

    The bike rolls freely when the clutch is engaged by the way...
     

  2. Greg58

    Greg58 Member

    You will have that on a new engine sometimes, I would remove the right side cover and check the small gear mounting bolt/screw. Add a small amount of grease where the two gears mesh, not too much or it will get on the clutch pads when the engine gets hot.
     
  3. Hello Moto!

    Hello Moto! Active Member

    Thanks I'll try that. I just thought it was weird because my other motor didn't have this issue.
     
  4. Hello Moto!

    Hello Moto! Active Member

    Let me make a correction here. It makes the noise when I am just letting off the gas and not pulling the clutch. Engine braking I have heard it called before. So when I'm goin along and just let off the gas it makes the noise. When I pull in the clutch it doesn't make the noise. Sorry for the confusion.

    I did add a little grease.
     
  5. Timbone

    Timbone Active Member

    it could be...the little gear inside he clutch cover popping out and hitting the cover. an idea.
     
  6. Hello Moto!

    Hello Moto! Active Member

    I don't think that's it. I loosened up the flower nut on the pressure plate a tad and ran it with the cover off briefly. The noise was still there but maybe a small bit less dramatic.

    I hope it's not a bearing or something.

    Maybe it will work itself out after a little mileage? I just hope it's not something really damaging. I didn't have this ever happen at all with my other motor. I just decided to mount this one for shits and giggles but now I'm not laughing o_O
     
  7. Greg58

    Greg58 Member

    The only way the small gear can hit the cover is because the mounting screw is loose or the crankshaft has way too much side play. What you described is a result is a result of gear teeth chatter, since we can't adjust the depth and back lash we are kinda stuck with what we have. If you run it with the side cover off watch both gears for excessive wobble or run out, you can replace either if so. One of my engines from eBay was pretty bad , after a few hundred miles its hardly noticeable.
     
  8. Hello Moto!

    Hello Moto! Active Member

    Funny thing. My brand new GT5A makes the same noise as that gasbike motor! I guess I can live with it but damn it's annoying. I'll double check some things tomorrow but if it's gonna make that noise...Oh well I guess. Not exactly impressed.
     
  9. Frankfort MB's

    Frankfort MB's Well-Known Member

    The more you ride it the more it comes out.... I wouldn't worry about it, but also in the type if it blows the crank out the jug I'm the first taking pictures lol
     
  10. jaguar

    jaguar Well-Known Member

    the primary gear and th clutch gear do make a lot of noise. I hastened their mating process by removing all grease and putting valve grinding paste on and left it on till the noise was much reduced. I looked and the gear edges were then rounded off. I then spray cleaned them off and applied grease.
     
  11. Hello Moto!

    Hello Moto! Active Member

    Thanks man lol
    Thanks. I guess I'll ride it til the sound either goes away or at least becomes a lot less noticeable :)
     
  12. jaguar

    jaguar Well-Known Member

    without the valve grinding compound that may take a year
     
  13. Hello Moto!

    Hello Moto! Active Member

  14. jaguar

    jaguar Well-Known Member

    or 12 months, whatever you prefer
    ha! no, really I shouldn't be quoting time but rather distance which I'm not sure of.
    But why would you want to put up with that noise at all? Just fix it! jeesh
     
    FurryOnTheInside likes this.
  15. Hello Moto!

    Hello Moto! Active Member

    Well it sounds simple enough. I may try what you mentioned. Is there any thing important I should be aware of so I don't screw something up? When things can go wrong, they do in my world lol.

    Do I apply the valve grinding paste between all the teeth of both the primary and clutch gear? I've never removed these gears before so I don't really know exactly how to perform that action. If I disassemble the clutch I'm afraid I may not get it back together right.
     
  16. crassius

    crassius Well-Known Member

    sounds a bit like you didn't apply heavy grease to those gears then - read about doing that and see if it helps the noise
     
  17. FurryOnTheInside

    FurryOnTheInside Active Member

    I think if Jaguar doesn't specify, it means there's nothing too specific to look out for. :) I think you can just go ahead and degrease the gears in situ and slap on a bit of paste. It should distribute itself? *shrugs* Dont spread grease onto the clutch pads. :)
    I'm kind of surprised you haven't already had to remove the ring gear though, to grease the ring gear bearing through the three holes in the rear. Mine was so dry! Not saying that the noise is from there.. it certainly is not.
     
  18. Hello Moto!

    Hello Moto! Active Member

    Sorry I'm not real verse in engine anatomy..I'm guessing the ring gear is the little gear that drives the bigger clutch gear? Please correct me if i'm wrong. I'd be willing to give that a shot too whether it's the problem or not. If its bone dry it probably should have some grease yeah? Also is there a specific type of grease I should use on the gears as well? I'll see what I can find to read on greasing the gears.

    Thanks
     
  19. FurryOnTheInside

    FurryOnTheInside Active Member

    My terminology may be wrong too!
    It's the big gear. I have no idea what state the bearings are in on Grubee engines. Older bad generic engines had blobs of metal in there instead of balls, newer generics' ring gear bearings can be dry or dry up and stick (from hot storage?) such that the clutch appears locked and just has to be unstuck with a bit of force. The bearing in between the clutch pads to separate it from the three pronged clutch shaft end thing is what let's you coast, or rev it up with the clutch disengaged. So the noise can only be from there if it happens when the clutch is disengaged/open. So NOT when engine braking.
    It's just that it is such a critical bearing that personally I would check it and add a little LITTLE bit of grease with a syringe and not forget to do it again sometine. But yeah that job does entail removal of the ring gear and the three prong business in the middle so you can combine the two jobs. It's just a puller.
    The grease for the gears is tacky grease, can be red, I'm no grease expert, just needs to not fly off or get into the clutch pads. I don't know what Grubbees are like for gear alignment/true though.. I know the cheaper kit engines can be awful, the small/primary gear not being on straight, visibly when you turn the crank. I think someone mentioned that you fix that by buying a new small gear.
     
    Last edited: Jun 7, 2016
  20. Hello Moto!

    Hello Moto! Active Member

    Thanks for the replies guys. I think my first order of operation is to try and grease the gears as crassius suggested. I've found plenty of posts on that and I'm 99% certain I can't F*** that up! Don't want it in your clutch pads..got it ;)

    If that doesn't seem to help I may dive in to the nastier bits.
     
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