crankcase crack By drahken (Read 677 times)

[drahken]

yea so i got another left half case crankcase side for my scooter.  i stuck the new one side i got with my other scooter half cause the other part was stripped, in a few bolt holes.  and then when i look through the crankcase, i seen a little, small sliver of light.  i was wondering, is this normal?

i stuck the side that went with it on it, and held it together and there wasnt no slivers. 

just wondering if this is normal.   it's just a small hair like crack of like, not sealing.

this motor uses liquid case gasket sealant.  im just wondering, is this normal?
trying to figure out if this case half, is good.  its original half i dont have no more.  it was broke.  this side was fine.  it was broke, from i dont know what.

[Bashan]

No man, I can't think of any spot on the case where you could look through and see light. There's a lot of oil throwing around in there and if there's an opening it will come out. Can you get us a picture? Rich

[cyborg]

i think he's talking about the mating halves Rich,,,the new case half doesnt exactly follow the other,,, i think a little block sanding is in order on the high spots but you must mark everything go slow and be very careful

[drahken]

i was thinking it was too big of a crack to be usable. it had a line on the bottom and when i pulled it apart after 10 miles there was dirty and it was dirty around there. i thought it was blowing out oil there. and theres another spot too,

this motor was overheated. the topend bend the head gasket. the rings broke. dont know about this case. maybe test an old crank in it. and it would be a lot of block sanding. the cracks of light are like not small enough but the one goes for like 3 inches so you can, see how much it would be cracked, its not that much. though. its not that bad, but id say 2 1/2 inch of light. you can see the light though its not like barely, peeking through, its a small deformed, spot.

[Alleyoop]

Take a picture of WHERE this casing problem is, If it was by the crankcase oil would be squirting out by the quarts. So where is this deformed part on the case PICTURE PLEASE and we can then tell you have a problem or not.
Alleyoop

[drahken]

the head gasket was actually warped, on the top. the round hole for the piston? it was oval. ill get a picture when its day and i get the cases out and put them together. i dont know how you could, keep the case flat. i could see a high spot. this is the whole case and would there be enough case and centering. id say yea. but itd be hard to center it up after you sanded one half lower down. the crank never sits center in the case after you rebuild.

[drahken]

tried to get the motor back out to take pictures, but its so wobbly it wont sit down straight.

the crankshaft was warped, wasnt turning straight. i thoght maybe i installed it messed up.. the wobbling where i couldt set them straight i was doing that when i installed the motor. done the build. i didnt have the bolts laying around and hunted them down for a minute but the motor was still, rocking. .. i didnt even know if i had th ebolts straight, i just tightened them straight down. torque value.
think the space was actually sucking in small rocks. i havent looked over the cylinder, maybe i looked in it. after i took the one hafl of the motor off, I spun the crank and seen it wobbling both, ways. could tell pretty easy. the variator side bearing, got shot. thats how it spun after i took off the fan side of the motor. it was dirty between where the cracks where. and i noticed, some pitting, on my case. its alright though. more pitting, than before. though. thats the thing and it sucks. and i think i may of took a little look in the cylinder, and it was fine.
only rode it 10 miles. crankshaft, had lost, .5mm of material, from what? i dont know, around where the seal, spins.

[Alleyoop]

I don't want to offend you but I suggest you just get a new motor, you are just pissing away money on parts and the case is just shot. If the crank wobbles that means the case where the bearings ride are shot.
Alleyoop

[Guitarman]

Burn it BURN IT! YEAH BLOW THE FREKIN THING UP! HOW HIGH WILL IT FLY?


Just get a new one man... Way cheaper and much fewer headaches.

[jct842]

Yup by the time you change all the bad parts you will have way more than a new motor costs.

[drahken]

see, i had a motor and had a extra parts bike. my motor, i needed a crank, and my left case half i had stripped a few bolt holes. it worked. i just decided that thta bike had a good crankshaft that spun fine, and a clean left case half. thought id swap.

crank, for some odd reason had half a millimeter of material missing from the seal part where the crankcase seal sealed, around it, on the lip. supposed to measured out at 20mm and was 19.45-19.5mm. all i done was a little vinegar soak, (4hours) and a little wd40 and brillo pad, to shine it back up after hearing, and seeing vinegar dulled it. and wondered. but the arm was supposed to measure, 14mm. and measured 13.95. .. i didnt brillo there as much? dont know didnt retest it. i did compare these measurements to my crank i had just took out and the 19.45 was off from the 20.00mm i measured off my crank. the 13.95 wasnt off too much at the 14mm i pretty much measwured off the other.

anyway, whatever. i figured the cases came off a machine and they would fit each other. so i didnt test fit the cases together or nothing, looked clean.

but when i went to set them together, like test fit, when the motor was hot and i was sealing the case, it just wobbled on it. wouldnt sit together flat. so i just somehow, tightened the bolts together.

thats what i found when i tore it back apart. something was going on, it wouldnt stay running, after 10 miles.

the crank was blowing air. and i was test fitting the cases, after having to hold them together and just finger tighten the bolts in.

the thing was, i was using the right half of my motor which was good. and the crack, between the 2 halves, the 2 cracks where sucking in air. and little rocks. and starting to pit my case. if i hadnt of looked, it would of pitted my right case half up to where it wouldnt seal no more and i wouldnt have a flat, smooth seal area around my 2 case halves.

soo, good thing i checked. i still got my left case side. i retap the holes and stuff. or thread insert. my right case half is fine, just a couple of pit marks. its good i checked it and didnt keep running it. plus i was seeing black oily stuff starting to blow out on the side, of the motor. made me think air leaks, thought maybe my sealant didnt seal. but thought its too big of a hole, and the problem i had. need to check it.

10 more miles that case half might not of sealed.