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General Category => General Discussion => Topic started by: giusto on April 25, 2020, 06:50:24 PM
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I thought I would reach out and see if anyone had a particular trick I have not tried to unfreeze the pistons on my barn find
1968 Twingle ( PUCH) Sears Allstate
I found this several months back and I’m finally starting to tear into it a little bit… I knew the Pistons were froze when I bought it… I think these little bikes are so stinking cool.
Twingle=2 pistons, one cylinder
So I’ve tried some marvel mystery oil and some penetrating oil soaking for days… Then went to adding heat to the cast iron cylinder ... Both of those cute little cylinders are stuck down near
BDC... Then I loosened the cylinder bolts and blocked it up about 3/8 of an inch to give me some room to knock on the Pistons with a wood dowel... still froze... taking my time and not going at it too hard... but I’d love to hear if anyone has a frozen piston cocktail mix that works well? Or anything else you can offer
Thanks in advance
(https://i.ibb.co/qMHg1qs/824767-A5-D2-F1-4-A2-F-A3-A2-18-A954122-CBD.jpg) (https://ibb.co/qMHg1qs)
(https://i.ibb.co/bbZGnjP/6-AF2-D3-D8-68-FA-46-F0-BCDD-6-B1-E181-DEA48.jpg) (https://ibb.co/bbZGnjP)
(https://i.ibb.co/6RHbBr4/40304-B6-D-A8-DD-477-E-8808-618792-B0754-E.jpg) (https://ibb.co/6RHbBr4)
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Your doing it right, patience , penetrating oil , and time. After a few days soaking i would heat the barrel with a propane torch evenly, and then hit the piston with some canned ice. Do this a couple of times and then try some light taps with a wood block, if no gain, repeat
https://shop.advanceautoparts.com/p/crc-freeze-off-super-penetrant-11.5-wt.-oz.-05002/7080144-p?product_channel=local&store=5961&adtype=pla&product_channel=local&store_code=5961&gclid=CjwKCAjwv4_1BRAhEiwAtMDLsoH8iNiU57UrXsokojmCmERzPpYpJHgPd97kCAyKA01DrRkgH6MVZBoCFugQAvD_BwE&gclsrc=aw.ds
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The old tractor restoration bunch near me uses Kroil and a piece of oak as a drift and time, sometimes weeks give it a bit of a tap each day. What size hammer is a matter of common sense, but a 3lb. may be overkill.
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Put it in the oven for some heat cycles to help break the bond
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So far no hammer....hard rubber mallet on a wood drift a bit smaller than the bore.
Heat and col heat and cold....soak soak soak....
john I may do that but my wife will come after me with a rolling pin111 :thewife: :thewife:
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I've got plates to use hydraulic pressure, the wooden plugs carved to match my V7 Sport's old stuck Pistons for hammer & press and more. I've soaked a wide range of engines and never found any recipe that worked particularly better than anything else. Sometimes they free up. sometimes, no matter how long you soak them, there's nothing that soaking will touch.
When I've got a bike with a cast iron cylinder with Pistons down in the bore and the cylinder can be freed from the cases like your engine, I use a rosebud tip on an oxy/act torch to heat the entire cylinder slowly & evenly from the outside via fins. When it's really hot, pour some engine oil into the bores on top of the pistons. I use used engine oil because its cheap. It will bubble and boil and smoke and stink like crazy. Give it a moment to settle down. When the volcano activity subsides enough rags or similar as like potholders, grab the cylinder and give it a careful tug. They usually come right off. I try to not pull the cylinder completely off until the oil cools to avoid spilling the hot oil. You're done in 20-30 min. Never had a cylinder crack or fracture. Never had a fin break. Piston is usually not damaged by the process. It's lots easier to wreck parts doing it other ways. Btdt. For cast iron cylinders, this is my preferred approach.
Hopefully everyone understands that this isn't a shorts & flip flops kind of procedure...
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I've been having fun with mine! Only six miles so far (it's not legal yet).
Video from last Sunday: https://flic.kr/p/2iTBXje
Full album: https://flic.kr/s/aHsmLsYoYc
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Hi Charlie, How are you?
I haven't been in your neck of the woods in a few years.
Nice photos....I especially like the CA Naval base sticker!!!
Yours looks like the 250 or 175? Mine is the 125...very cool little bike
Cheers
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Hi Charlie, How are you?
I haven't been in your neck of the woods in a few years.
Nice photos....I especially like the CA Naval base sticker!!!
Yours looks like the 250 or 175? Mine is the 125...very cool little bike
Cheers
Mine's a 250. 125? Are you sure? AFAIK, the Twingles were only 175 and 250.
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All my antique outboard buddies swear by Kroil, heat and patience. We deal with stuck piston a lot.
kk
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So far no hammer....hard rubber mallet on a wood drift a bit smaller than the bore.
Heat and col heat and cold....soak soak soak....
john I may do that but my wife will come after me with a rolling pin111 :thewife: :thewife:
That’s brilliant! Cut the handle off the rolling pin and it’s a perfect piston pounder :evil: :grin:
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Mine's a 250. 125? Are you sure? AFAIK, the Twingles were only 175 and 250.
You are correct sir...I misspoke...just looked up the serial number its a 67 SR175...Thanks Charlie
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Brute force shouldn't be used in breaking the pistons free. When they're ready to move, they will. Equal parts Power Steering fluid and Acetone works better than most penetrating oils. Any use of a hammer should be used to induce dissonance between the different metals so they vibrate at different frequencies and break free. That doesn't take much of a tap.
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50:50 mix of acetone and ATF.....and tincture of time