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Saito FA125 squeal sound

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Old 09-19-2013, 04:16 PM
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bob8619
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Default Saito FA125 squeal sound

I have read a few threads about this but have not yet seen one that explains what it is. I bought this engine new on this forum marketplace and towards the end of breaking it in, it began to squeal or squeak. It reminds me of the sound an old worn out belt makes in your car. The noise is there throughout the rpm range but more noticeable at idle since the engine is quieter. The sound comes and goes. I would say the trend seems to be that it comes back after its been running for a few tanks probably. I don't know if this is the same type of sound that others have experienced or if this is some internal breakdown of sorts. Any of you guys dealt with this type of issue with your Saitos?

Thanks

Bob

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Old 09-19-2013, 05:57 PM
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Not a Saito but an OS after I rebuilt it, turned out to be a bad bearing. The bearing was sticking and the engine was getting very hot in the front on the case. In the glow engine forum there is a factory support section and I think there is still one for Saito. You can contact one of the reps from there.
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Old 09-19-2013, 06:02 PM
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Thanks Mr Beard. I also have a question about something else. Sometimes I will put the electric starter on and it'll pop and shoot a burst of fuel out of the carb. Why and how can this happen with an electric starter ?
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Old 09-19-2013, 06:44 PM
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I'm not a Saito guy but it's one I will work on. John Buckner is a bunch more experienced with them then I am but it sounds like you have fuel still in the combustion chamber. There are a few ways this can happen, tank siphoning if the engine is inverted? Over rich low end? Valves out of adjustment? It's one of those things that is hard to understand on the net. I had been told for years that these four strokes can start up without a glow driver on the plug when you flip them over before starting. I had never seen it happen but been told about it by a number of people. I had just finished telling my student about it when I was getting ready to start his Saito 100 for the next flight. I flipped the prop and talk about a surprise, that engine started right up!! Now when I roll them over I grasp the prop. You may be over priming the engine before you start it? John may chime in here with a better answer. I was just over in the glow engine forum and Saito does still have factory support. It's a good place to go learn about your engines. I have been using OS and YS for a lot of years but still go to there forums and pick up new info. Go on over and surf there threads, well worth reading.
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Old 09-19-2013, 06:57 PM
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Thats good to know, I never knew they could start without a glow driver on it. I could have lost fingers many times, SCARY! But yeah my engine is inverted. I found some other thread where its been discussed, I guess this engine is really prone to backfires if over primed. I have had next to no luck with using a chicken stick on this engine, when it does fire it is always running backwards. When I use the electric starter I don't hand prime it I just put the starter on it and let it draw the fuel. So maybe it is siphoning....
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Old 09-20-2013, 11:44 AM
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I have only had it happen the one time and with a Saito 100. Inverted, that makes it sound like the tank is a bit high and the cylinder is flooding a bit, when you attach the driver the plug is firing off the fuel inside the head. Backwards starting and running is usually a lean condition. Sounds like it is a bit out of tune. I would check the tank to see if the center line is lower then the needles so it doesn't siphon, adjust the valves then retune the engine. Saitos seem to like a fatter low end then OS and YS engines. I always check the valves, even on a new engine to make sure they are adjusted correctly. I only use 15% nitro in all my glow engines but the higher the nitro the easier they are to tune. A lot of YS users use 30% heli fuel, I don't bother but I was taught to tune engines by someone that was very good at it. Read the posts in the Saito forum and you will pick up a lot of pointers.
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Old 09-22-2013, 08:09 PM
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Originally Posted by bob8619 View Post
I would say the trend seems to be that it comes back after its been running for a few tanks probably. I don't know if this is the same type of sound that others have experienced or if this is some internal breakdown of sorts. Any of you guys dealt with this type of issue with your Saitos?


Bob
A friend of mine had a Saito 125 with similar problems. It seems this engine has an issue with the front bearings, in that they do not get adequate lubrication. He ended up adding a nipple + vent line near the front bearings (after changing the first set, which was shot after a few hours of running), thus apparently enabling the oil to get to the bearings more easily. It's weird that you should have to make such modifications to a new engine in order for it to work properly, but that's what he had to do.
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