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50cc Gas Engine Rebuild

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Old 09-11-2012, 03:17 PM
  #1
jp1961
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Default 50cc Gas Engine Rebuild

Need advice rebuilding a Tanaka 50cc gas engine. Bought a new piston/rings but cylinders are no longer available. Should I hone the cylinder or leave it alone? I've heard if the cylinder is chrome plated or Nakasil plated it could do more harm than good.

Thanks

Jeff
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Old 09-11-2012, 03:49 PM
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Default RE: 50cc Gas Engine Rebuild

You heard right as trying to hone the cylinder would most likely make it worst than it already is. All you need to do is to use some 400 grade emery with some oil and by lightly hand rubbing in a circular motion remove the glazing from the cylinder which helps the new rings to bed in. Wash and dry properly and then oil lightly before fitting the new piston and rings.

Karol
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Old 09-11-2012, 05:30 PM
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Default RE: 50cc Gas Engine Rebuild

Watch out DLE,JC EVO is coming
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Old 09-13-2012, 06:51 PM
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Default RE: 50cc Gas Engine Rebuild


Quote:
ORIGINAL: karolh

You heard right as trying to hone the cylinder would most likely make it worst than it already is. All you need to do is to use some 400 grade emery with some oil and by lightly hand rubbing in a circular motion remove the glazing from the cylinder which helps the new rings to bed in. Wash and dry properly and then oil lightly before fitting the new piston and rings.

Karol
Some types of emery & sandpaper can embed particles in cyl wall. Be sure too use a hand wire brush and soap & hot water to remove any grit. Then re oil right away.
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Old 09-14-2012, 04:24 AM
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Default RE: 50cc Gas Engine Rebuild

Good point Capt,n as the few that I have done I used an old toothbrush to scrub clean the cylinder bore.

Karol
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Old 09-14-2012, 06:41 AM
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Default RE: 50cc Gas Engine Rebuild

captin, would a brass wire brush be more appropiate than a steel one? Dan.
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Old 09-14-2012, 07:21 AM
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Default RE: 50cc Gas Engine Rebuild

Don't think it really matter what you use as long as you get the cylinder walls clean of all possible residue before reassembly.

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Old 09-14-2012, 07:51 PM
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ORIGINAL: All Day Dan

captin, would a brass wire brush be more appropiate than a steel one? Dan.
It does not matter steel or brass...just go easy on how much pressure you use. Maybe stay away from a brush with stiff wires. A good brush for cleaning dentures may work fine. Capt,n
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Old 09-16-2012, 08:21 AM
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Default RE: 50cc Gas Engine Rebuild

CAN SOMEONE PLEASE TELL ME,WHEN ENGINE IS HOT IDLE GOES UP,IS THAT RICH ON LOW OR HI NEEDLE
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Old 09-16-2012, 10:30 AM
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Default RE: 50cc Gas Engine Rebuild

Having a rich mixture on the Low mix or Hi mixture does not make a engine run hot. Too lean a mixture will make engine hot...also not enough airflow over cooling fins and the wrong spark timimg will make a engine run hot. Time to start reading a lot more about this and talk with a person at a flying field who knows about engines. Goood Luck.....Capt,n PS Make sure you have the right oil in the gas at correct ratio.
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Old 09-17-2012, 06:51 AM
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Default RE: 50cc Gas Engine Rebuild

SOLO48 the engine is a little to lean on the low end.
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Old 09-17-2012, 06:52 AM
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Quote:
ORIGINAL: SOLO_48

CAN SOMEONE PLEASE TELL ME,WHEN ENGINE IS HOT IDLE GOES UP,IS THAT RICH ON LOW OR HI NEEDLE
Solo, if you are talking about the idle speeding up after engine warm-up, then I think the low needle might be just a touch lean. I have a couple of engines that do this and I adjust around it ( with trims ) since they perform great in the air.
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Old 09-17-2012, 08:18 AM
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Default RE: 50cc Gas Engine Rebuild

thanks for the info.will try next time at field
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Old 09-17-2012, 08:36 AM
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Default RE: 50cc Gas Engine Rebuild

Yes engine is at normal idle .After 5 min flite when i go to land idle is very hi
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Old 09-17-2012, 09:37 AM
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Default RE: 50cc Gas Engine Rebuild

After you land your airplaneand the Idle is high....thats the time to adjust your trim Idle speed on TX also. A lot of RC people have a radio(TX) that has at least 2 different Idle speeds and you can use the lowest one on landing. It sounds like you need to experiment a little on getting things right with the Idle. Do not worry ifthe engine soundsrich on idle if the engine is cold. If your engine is not broke- in...that should all get better too when it gets broke-in. Capt,n
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