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Post by Fox on Mar 13, 2012 18:32:05 GMT -5
I got a 157QMJ in the shop that was run with little oil The piston and cylinder are ruined. I got the cylinder off but I can't drive the piston pin out. It's tight inside the connecting rod. The piston doesn't want to swivel easily. It'll move if you grab it with channel locks. I've been hitting the pin pretty hard with a 3/8 extension trying to drive it out but it won't budge and I'm afraid I'm gonna bend the connecting rod if I hit it any harder.
Will heating the piston help/work? Any other technique(s) I can try before I go buy a torch?
Thanks
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Post by reveeen on Mar 13, 2012 18:42:09 GMT -5
If the pin is stuck in the piston heating the piston with a propane torch (like you would use for plumbing) should help.
If the pin is stuck in a trashed con rod bearing..... you can count on the rod being fubared anyway.
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Post by Fox on Mar 13, 2012 18:49:34 GMT -5
Well, on a 150cc 4 stroke there is no upper con rod bearing like on a 2 stroke. The pin rides directly in the rod end and it has a hole for oil to get into the center pivot and oil splashes on either side of the rod onto the pin as well. It's a closely machined fit. The oil acts as the bearing. I had one a long time ago like this. I took the crank out of the cases and took it to a machine shop. They said come back in a couple of hours. I returned and it was removed. I asked them how they did it and they just said, "We have a few tricks for getting those out" He didn't want to tell me...
Anyway, I reused that rod and crank and it seemed okay with a new piston pin in it.
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Post by 90GTVert on Mar 13, 2012 19:02:43 GMT -5
They prob pressed it out. Maybe you could use a clamp and a couple sockets to press it out? Put a socker bigger than the pin on one side and a socket smalller or basically the size of the pin on the other. Press it out that way?
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Post by Fox on Mar 13, 2012 20:42:47 GMT -5
They prob pressed it out. Maybe you could use a clamp and a couple sockets to press it out? Put a socker bigger than the pin on one side and a socket smalller or basically the size of the pin on the other. Press it out that way? That's a really great idea! I'll try that on the next one cause I went out there and just blasted on it really hard and after about thirty good whacks it shot out and flew across the room. lol I didn't particularly like hitting it that hard but torches ain't cheap. Afterward I took another pin that wasn't damaged and tried to insert it into the rod and it would only slide in on one side a little bit so I took some 400 grit sandpaper and rolled it into a tube and inserted one end of it it my drill chuck and honed it out a little bit at a time til the pin slid in freely enough so it will spin in the hole. It has a little tiny bit of side play in it. Like a half a thousandth or whatever. I'm going to go with it. |
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Post by 90GTVert on Mar 13, 2012 20:50:40 GMT -5
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Post by stepthrutuner on Mar 13, 2012 21:06:31 GMT -5
One other technique would be to draw it out with a deep socket, a bolt, washers and nut(s) and a lubricant/penetrant.
A lot less trauma is involved.
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Post by jmkjr72 on Mar 13, 2012 21:08:38 GMT -5
yeah even big stuff all you need is a little propane torch
and if you need a bit more heat then a map gas torch isnt that bad either
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Post by rocketdog on Mar 13, 2012 21:29:50 GMT -5
They prob pressed it out. Maybe you could use a clamp and a couple sockets to press it out? Put a socker bigger than the pin on one side and a socket smalller or basically the size of the pin on the other. Press it out that way? This is the ticket. It will come out with two sockets and a C clamp. However, like was mentioned, the small end of the rod might be shot. Good luck. |
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Post by Fox on Mar 13, 2012 21:41:19 GMT -5
One other technique would be to draw it out with a deep socket, a bolt, washers and nut(s) and a lubricant/penetrant. A lot less trauma is involved. Another good idea.  I knew if I asked I'd receive but I got impatient. Next time I'll definitely try the clamp and/or the bolt trick. I was just looking at the ones with a ignitor at HF and they were only $18. How much is a propane cylinder? they aren't listed cause I guess you can't ship 'em. Have to buy them in person. |
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Post by reveeen on Mar 14, 2012 2:37:40 GMT -5
How much is a propane cylinder?
There are 2 types. The tall skinny ones, that you are supposed to use, cost under $5, and tip over easy, or the squat ones, found in the camping section, cost about the same, and don't tip over so easy.
I use the camping ones.... last I bought was at wally-mart, 3 for $10.
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vvtr
Scoot Enthusiast
Posts: 243
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Post by vvtr on Mar 14, 2012 4:38:19 GMT -5
Dont hit it to get it out as you will damage the rod and big end.
Put a long bolt or length of screwed rod through the a 1/2" spark plug socket against the piston, with a washer and nut on the end.
Pass the other end through the hole in the pin, with just a nut on the end.
When you screw the washer end in it will extract the pin
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vvtr
Scoot Enthusiast
Posts: 243
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Post by vvtr on Mar 14, 2012 4:40:22 GMT -5
Sorry stepthru... Didnt see u had already suggested this lol.
Great minds eh!
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Post by bradswims11 on Apr 3, 2012 2:47:30 GMT -5
Just use a can of Penetron. 25secs later and a tap or two the thing will be done. IF that doesn't work then you are f**cked
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Post by stepthrutuner on Apr 3, 2012 13:57:46 GMT -5
Sorry stepthru... Didnt see u had already suggested this lol. Great minds eh! You got that right! Good riding mate.... :thumb: Reg |
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