Clutch and pressure plate

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marioaz

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Dec 15, 2008
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Is the pressure plate supposed to be centered on the clutch plate? New Grubee and the first clutch had a wobble and the pressure plate rubbed the ring gear. Vendor promptly sent a new clutch. This one doesn't rub but definitely not centered.

If the picture posts it is of the first one that rubbed. The new one is almost rubbing.
 

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Norman

Norman

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Jan 16, 2008
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Some of these engine will rub the case with the big gear, Use a dremel with a carbide burr or sanding drum to grind the case for clearance. Your engine might have been produced after an all night binge of heavy drinking or what ever they do in China.
Norman
 
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marioaz

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Norman, that's a good fix for the gear rubbing on the housing. In the pic, it's the pressure plate off center and rubbing on the ring gear. The replacement clutch unit finds the pressure plate not rubbing but almost and way off center. Thanks for the responses before I contact the vendor again.
 
Norman

Norman

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Yes the pressure plate should be centered

Oh Dang! I didn't really see that the first time I though your big gear was rubbing the case now i see the silver pressure plate touching the big gear. looks like something is off center there and I'm not sure which is off the silver plate or the as you caledl it the ring gear. are the bearings sloppy? First time I've seen that you might want to get a complete different engine if its still new. There's bearing in the ring gear and they are not in a cage if it comes apart they will scatter to the 4 corners of the earth. I wonder if you might have some bearings missing or none at all I think there is around 50 or so 3mm ball bearing not sure on the count I'm probably off on the count.
Norman
 
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Norman

Norman

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either your clutch is not machined/drilled in the center or your main shaft is bent or off centered that looks weird!
I think they should send you a replacement engine.
Norman
 
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marioaz

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Dec 15, 2008
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Update. Figured it out. Measured from center of shaft to inside of big gear and it was true. The pressure plate center hole, and 3 locating pin holes are over 1/16" off center. If you look closely at the full pic, you can see the locating holes are inside and outside the beveled/countersink surface. It's obvious it slipped on the jig, or whatever it is they use. Joel at USA Bike Motors is sending another pressure plate. Super prompt friendly service from those guys in Tucson!
 
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Bikeguy Joe

Bikeguy Joe

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Jan 8, 2008
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marioaz said:
It's obvious it slipped on the jig, or whatever it is they use.
Click to expand...
I think that is called "Holding it between your knees while drilling it with a single speed drill and a made in China bit.".

That's funny Joe I'll bet your right!
Norman
 
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Bryan Smith

Bryan Smith

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Dec 1, 2008
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I'm Having the exact same problem with my new Gen II Grubee engine.
I sent a message in the "contact us" section of the USA Bike engines website but haven't heard anything from them yet. the 3 guide pin holes on the pressure plate aren't drilled concentrically with the rest of the disk causing it to rub. A new/better pressure plate would cure the problem. scratg
 

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Bryan Smith

Bryan Smith

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marioaz said:
Doesn't look like the pressure plate is rubbing on the big gear. Try removing the P plate and rotating so the plate is using different guide pins.
Click to expand...
Thanks marioaz... I tried that already...I ground a little off the offending edge of the pressure plate too, but it still scrapes some. The pins are centered correctly so no matter how I remount the plate, The edge rubs.
 
Bryan Smith

Bryan Smith

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If I can't get it replaced...(which I think it should)...I'll have to figure the hole circle diameter for the 3 pins, figure how to center the plate on a jig and scribe a new hole circle and then drill 3 new holes (60 degrees off from the original botched up holes). This should only take me the better part of a day.
 
reg454

reg454

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Jan 11, 2009
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You could always grind off a little on the clutch plate to true it up a little bit so it wnt grind on the big gear.
 
Bryan Smith

Bryan Smith

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reg454 said:
You could always grind off a little on the clutch plate to true it up a little bit so it wnt grind on the big gear.
Click to expand...
I did grind it some, but I'll probably just grind it a little more and forget that it's off center in the end. I was probably getting too elaborate for my own good. I tend to do that sometimes. .bld.

I forget sometimes that these are built by people in a communist country. I heard a Russian comment once back when Russia was communist... "we pretend to work and they pretend to pay us."
 
Bryan Smith

Bryan Smith

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Just an update-- Joel from USAbikemotors contacted me and sent a new clutch plate on his nickel. All I had to do was show a picture of the ctutch plate that was rubbing. He asked that I send back the bad one so he could get credit for it. Great service from these guys. The problem I have now is the bearing race holding the disc with the pucks is pressed together and is working it's way off. Probably needs spot welding too.
 
Bryan Smith

Bryan Smith

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Dec 1, 2008
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I took my clutch off today to spot weld the bearing race on.

The action of the bevel gears wants to twist the large bevel gear as it runs, working the pressed on bearing race loose over time. If it works off enough, the ball bearings fall out and the clutch self destructs.

I Took it all apart and decided to wash out the old grease and oil in kerosene. I looked at the pan after cleaning and there was about 1/2 a thimble full if metal shavings. The base plate was very rough with some burs from machining so I buffed it with a wire wheel brush on the grinder. I pulled apart the bearing over a cup to catch the ball bearings...note to self....use a larger container next time.

After combing the floor with a light and magnet I retrieved 54 of the little buggers. I cleaned the bearing race. ran some grease around the outside, and started setting bearings in the grease. I set the large bevel gear on the race and started working the race on to the clutch base pressing it together in my small vise. I tack welded it on in three places and reassembled it after sanding my clutch pucks down to fit in the slots more loosely as suggested by Pablo.

Those pucks really are made of old tires! I saw cord and steel belting sticking out the side of them.
 

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Ode

Ode

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Jan 9, 2009
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Chicago
Norman said:
Yes the pressure plate should be centered

Oh Dang! I didn't really see that the first time I though your big gear was rubbing the case now i see the silver pressure plate touching the big gear. looks like something is off center there and I'm not sure which is off the silver plate or the as you caledl it the ring gear. are the bearings sloppy? First time I've seen that you might want to get a complete different engine if its still new. There's bearing in the ring gear and they are not in a cage if it comes apart they will scatter to the 4 corners of the earth. I wonder if you might have some bearings missing or none at all I think there is around 50 or so 3mm ball bearing not sure on the count I'm probably off on the count.
Norman
Click to expand...
Does the motor have to be laying on its' left side before accessing the insides of the clutch because of the ball bearings?...(which would mean draining the fuel tank or removing it first)

Ode
 
Ode

Ode

New Member
Jan 9, 2009
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Chicago
marioaz said:
Is the pressure plate supposed to be centered on the clutch plate? New Grubee and the first clutch had a wobble and the pressure plate rubbed the ring gear. Vendor promptly sent a new clutch. This one doesn't rub but definitely not centered.

If the picture posts it is of the first one that rubbed. The new one is almost rubbing.
Click to expand...

I partially opened up my clutch today to scope out the ball bearing situation, and even though the bearings were a bust (related parts appear to be pressed together), I was able to take some indicator readings on the driven gear of the primary drive, axial and radial, and think my motor must be way off spec.
Axial "wobble" is about 0.029" - 0.030" measured at the perimeter of the driven gear, as if the bore of the clutch was drilled out by a shaky, rice wine-infused, Asian hand and the axis of the bore is not perpendicular to the face.
Radial slop is about 0.015" - 0.016", all of this seeming to be in the very loose fit of the bearings. Even a dirt-cheap, bread-and-butter bicycle is going to have tighter bearings than this in any location: steering head, wheel axles or bottom bracket! Why am I surprised that the thing vibrates like a self-pleasuring toy?
What is the accepted range of "out-of-wackness" for these 2 specs, axial and radial?
Where do I get a "Workshop Manual" for my wacky Chinese, 66cc 2-stroke motor kit?
Is anyone "blueprinting" these shoddily made motors with any success?

Ode
 
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