maccrew
Scoot Enthusiast
Custom painted f-act
Posts: 193
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Post by maccrew on Mar 8, 2012 0:40:01 GMT -5
ok long story short, me and my cousin riding his 150cc (last summer), weird metal clunking and rattling. barely stays running, if you get it started it only moves about 2mph for about 10ft, then it shuts off. so today we take the valve cover off, once off we find, (i believe is the cam shaft)see pics below, the ring the red arrow points at has no ball bearings in it anymore and is just flopping around. i believe this is the only issue. soon we will be getting to what i believe is the crank shaft that the variator connects to. have only found 1 ball bearing so far. the gaskets all look fine no cracks so prolly will just reuse those, but if you know of a very cheap set let me know. so we need the part in the picture im about to show you. im pretty sure this is the only problem with it, any input please help.   |
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Deleted
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Post by Deleted on Mar 8, 2012 2:48:11 GMT -5
id be wondering why that happened in the 1st place
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maccrew
Scoot Enthusiast
Custom painted f-act
Posts: 193
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Post by maccrew on Mar 8, 2012 3:00:17 GMT -5
well, what can cause that, he did run it out of oil and ran it for a few days that way, so far everything else checks out fine that i can see. there are no other broken parts or anything, he did ride double on it like it looks like it was made for. might have exceded the weight limit, not sure.
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Post by 90GTVert on Mar 8, 2012 9:47:06 GMT -5
I weigh as much as 2 avg people and ride the hell out of my scoots, I wouldn't worry too much about that. Might be harder on them, but it shouldn't be causing the cam bearings to fail. Running an engine out of oil is very hard on the bearings. Aside from the obvious lack of lubrication in the bearings, it makes more heat from the added friction. I'd wanna check everything over thoroughly, especially all bearings in the engine, cylinder bore, piston and rings, bearing races.
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Post by Goosey on Mar 8, 2012 10:13:19 GMT -5
I have a spare stock cam for the 150cc, PM if you want it, $20 paypal (SH included) My bets on the lack of oil  |
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Post by Fox on Mar 8, 2012 14:27:09 GMT -5
Of course lack of oil did it. It's a wonder the piston didn't seize up or worse. I've seen a cam like that before, seized pistons, holed pistons, seized connecting rod bearings, and frozen Gudgeon pins all from running with little to no oil. Practically every single scooter that comes through my shop is low on oil and the oil is pitch black because owners don't check it or change it. It takes about 30 seconds and you don't have to be a master mechanic to do it. 49ccscoot.proboards.com/index.cgi?board=4ttech&action=display&thread=430 |
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Deleted
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Post by Deleted on Mar 8, 2012 20:12:14 GMT -5
well, what can cause that, he did run it out of oil and ran it for a few days that way That would do it and its time for a new crank, cam and top end. |
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maccrew
Scoot Enthusiast
Custom painted f-act
Posts: 193
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Post by maccrew on Mar 9, 2012 2:35:09 GMT -5
the crank and the piston/rings are fine, the only problem with it was the cam shaft, he just wants it running so he can sell it and tell the person what happened, whats wrong and whats been done to it. just wants it to start and move so the buyer can have it running at least. im just doing the work, he is calling the shots
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Deleted
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Post by Deleted on Mar 9, 2012 4:10:31 GMT -5
the piston/rings are fine Oh? what is the compression test reading? |
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maccrew
Scoot Enthusiast
Custom painted f-act
Posts: 193
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Post by maccrew on Mar 9, 2012 4:58:39 GMT -5
dont member the number exactly, but like mine was only like 5 less then it should be lol, i dont remember what the numbers are and stuff, also did the finger test and it forced my finger right off, like i have been told it should
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Deleted
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Post by Deleted on Mar 9, 2012 6:29:17 GMT -5
do it right or do it again |
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Post by rocketdog on Mar 10, 2012 9:08:15 GMT -5
Maccrew, suppose your right and the only thing damaged is that cam bearing. You'd better find those other balls before you try just a cam replacement. They just don't disappear.
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maccrew
Scoot Enthusiast
Custom painted f-act
Posts: 193
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Post by maccrew on Mar 11, 2012 2:41:22 GMT -5
i have taken the motor mostly apart, found 7 of 9 balls, after this issue first started on the thing, i have changed the oil a couple times before we took the top end off to find the barring broken, im thinking the other 2 have gone into waste oil from previous flushes, other then using good oil and running it right through to flush it, what else can i do to flush the motor the best?
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Post by Fox on Mar 11, 2012 8:40:58 GMT -5
On the engine I repaired after a cam fail I split the case halves on the fan/flywheel side and stuck a magnet on a stick in there to fish out all the metal. There is not only balls but there's some steel rings that are a part of the cam bearing as well that got chewed up in there. Got most of it out with the magnet and the rest got caught on the outside of the oil strainer after a little run time. I got lucky that the case gasket didn't tear on me so I just cleaned it up as best I could with some carb spray to remove any oil and used some Permatex gasket maker on it and it sealed up after a 24 hour cure time.  |
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Post by rocketdog on Mar 11, 2012 11:02:18 GMT -5
You could drain the oil and flush it with kerosene. A little in the oil won't hurt anything. JB weld a magnet to the inside of the drain plug to catch other bits.
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