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Old Nov 06, 2013, 10:02 AM
RAPTORKILLER
Joined Feb 2012
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So Im wondering wich engine I should choose for a Sbach 60" flying weight 5-5.5lbs , would a Saito 120 be to much?
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Old Nov 06, 2013, 01:43 PM
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danpos's Avatar
Canada, NB, Fredericton
Joined Dec 2011
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Originally Posted by I TOBOR View Post
Danpos, if the engine accelerated without the pressure line it means you have the engine set too rich.

Saitos' lower end is lubed by blowby past the piston. There is plenty or residual oil in the crankcase to do the job. I used to have a picture of my 2.20 with the residual oil still in the crankcase. There is a surprising amount.
So the fact that the plane accelerated while the fuel line was off of the nipple on the muffler means I am running the engine too rich?
I'm very surprised by that because it is running so well.

I'll go through the carb needle settings next time I take it out.
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Old Nov 06, 2013, 01:58 PM
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los36's Avatar
United States, TX, The Colony
Joined Nov 2012
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Originally Posted by danpos View Post
So the fact that the plane accelerated while the fuel line was off of the nipple on the muffler means I am running the engine too rich?
I'm very surprised by that because it is running so well.

I'll go through the carb needle settings next time I take it out.
I have experience with 2 Saito single cylinder engines: a 62 and 115. The 62 will not run well unless tuned within a few clicks of peak RPM. The 115 will run clean and smooth 1/2 turn off peak RPM. With this extremely small sample size, I am going to assume that the larger engines are less sensitive to mixture adjustments.
When your pressure line came off the muffler, your carb was getting less fuel and leaned-out your mixture.
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Old Nov 06, 2013, 03:35 PM
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I TOBOR's Avatar
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Danpos, an unusual characteristic of Saitos is that they will run very well when set very rich. You need to sneak up on the peak changing the HS needle one click at a time giving it a couple of seconds to stabilize between clicks. When you reach peak the next click will cause it to slow about 50 rpm. Ya gotta watch for it.
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Old Nov 06, 2013, 09:15 PM
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Canada, NB, Fredericton
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Originally Posted by I TOBOR View Post
Danpos, an unusual characteristic of Saitos is that they will run very well when set very rich. You need to sneak up on the peak changing the HS needle one click at a time giving it a couple of seconds to stabilize between clicks. When you reach peak the next click will cause it to slow about 50 rpm. Ya gotta watch for it.
Thanks for the tip.
Then after I reach peak rpm, richen it to the loss of 300 rpm.
Then set the low speed needle for the highest idle.
Then back the idle down to a smooth idle about 2000-2200 using the remote control.
correct?
That's how I have been doing this so far.
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Old Nov 07, 2013, 12:27 AM
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Canada, BC, Langley
Joined Nov 2007
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Originally Posted by danpos View Post
Thanks for the tip.
Then after I reach peak rpm, richen it to the loss of 300 rpm.
Then set the low speed needle for the highest idle.
Then back the idle down to a smooth idle about 2000-2200 using the remote control.
correct?
That's how I have been doing this so far.

One last step. Let the engine idle for ten seconds, then open the throttle to wide open. If the mixture is correct, the engine should pick up immediately (transition) to high speed smoothly. If the engine stops suddenly when you do this, the idle needle is set too lean. Richen it 1/16 turn at a time until it does, You may have to open the throttle a bit to maintain idle speed, If the engine stumbles, stutters then pick up, the idle is set too rich. Close the idle needle a small amount at a time allowing the engine to idle for a while between tests. Lastly, recheck the high speed needle.
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Old Nov 07, 2013, 02:22 PM
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Canada, NB, Fredericton
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Originally Posted by Arceenut View Post
One last step. Let the engine idle for ten seconds, then open the throttle to wide open. If the mixture is correct, the engine should pick up immediately (transition) to high speed smoothly. If the engine stops suddenly when you do this, the idle needle is set too lean. Richen it 1/16 turn at a time until it does, You may have to open the throttle a bit to maintain idle speed, If the engine stumbles, stutters then pick up, the idle is set too rich. Close the idle needle a small amount at a time allowing the engine to idle for a while between tests. Lastly, recheck the high speed needle.
Thanks.
I always flip the throttle to full and make certain the engine doesn't stumble before fltying.
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Old Nov 07, 2013, 02:35 PM
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I mounted the Saito Fa-80 on my plane and decided to make certain everything was well lubricated before starting today.
So I connected the after run oil bottle to the tube at the back of the crankcase vent.
The after run oil squirts right out of the front of the crankshaft seal with little pressure when I squeezed the after run oil bottle.
So am I right that I need to rebuild this engine and replace the crankshaft bearings?
Or can it be run like this where it rolls over smooth.

If I need to rebuild this engine where can I find a good rebuild manual or information on rebuilding the FA-80?
It's too bad really because it rolls over smooth and has good compression.
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Last edited by danpos; Nov 07, 2013 at 03:31 PM.
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Old Nov 07, 2013, 03:42 PM
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This is due to the bearing in front not having a rubber seal. If the bearings are smooth there is nothing to worry about. I didn't have a sealed bearing when I rebuilt an FA-80 and other than being a bit more messy, it's fine.

Greg
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Old Nov 07, 2013, 06:17 PM
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As Greg alluded to, even if you rebuild it the ARO will still come out of the front. This is actually a good thing, you know the oil got all over the cam and timing gears.
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Old Nov 07, 2013, 09:16 PM
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Thanks gkamysz and I TOBOR.
That's great news. I was hoping I didn't need to replace the crankshaft bearings.

This thread is a great resourse for us new saito guys.

Should I expect more than 9700 rpm with a13x6 MAS propeller on a Saito FA-80?
That is with the stock exhaust off my Saito Fa-100.
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Last edited by danpos; Nov 08, 2013 at 10:52 AM.
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Old Nov 08, 2013, 05:40 PM
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USA, TX, Teague
Joined Jul 2007
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Quote:
Originally Posted by danpos View Post
Thanks gkamysz and I TOBOR.
That's great news. I was hoping I didn't need to replace the crankshaft bearings.

This thread is a great resourse for us new saito guys.

Should I expect more than 9700 rpm with a13x6 MAS propeller on a Saito FA-80?
That is with the stock exhaust off my Saito Fa-100.
Ditto on lube and bearings

Your "RPM expectation" question requires a multi answer.

Should you EXPECT more? No

Can you GET more? Yes

Is 9700 about right? Yes

9700 is about right on RPM requirements on a 4-stroke engine. This will allow it to unload to around 10500-11000 in the air and you do NOT want to spin them any more than this or things CAN start swapping places....and thats bad

All depends on your plane and your flying requirements.

I have a Saito 91 that I spin 4800 RPM with an reliable idle of 900-1000. STOL bush plane (Telemaster)

I have a OS91 in a beater TwisT and spin it 13000+........I also have valve springs IN STOCK for it

Thats the long answer
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Old Nov 09, 2013, 05:55 AM
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United Kingdom, England, Lancs
Joined Apr 2005
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Does the Rexel digital tacho work ok with a Saito CDI?
The engine is the new radial FG-33R3.
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Old Nov 10, 2013, 04:57 PM
Flying is Living!
Savage, MT
Joined Mar 2008
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Originally Posted by Alcuy View Post
Has anyone purchased the new FG-57TS 57cc Twin Cylinder 4-Stroke Gas Engine? I am thinking about installing it in a Hanger 9 Quarter Scale Super Cub. Cutting the firewall to insert the carburetor looks a bit tricky and not a good practice so I may not go this way... but inserting a sealed thin-wall tube to keep fuel out of the fuse might do the trick. Still trying to decide...
There have been no responses to the above.
So the next question is on the FG-57. Anyone have one? If so, what experiences have you had with the engine? Thanks in advance!
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Old Nov 12, 2013, 06:11 AM
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United States, NY, St Lawrence
Joined Feb 2012
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Quote:
Originally Posted by VinceHaworth View Post
Does the Rexel digital tacho work ok with a Saito CDI?
The engine is the new radial FG-33R3.
If you do get it to read out the RPM value will be 3X the actual RPM.

While single & even firing twin CDIs fire 1X every revolution, the 3 cylinder radial CDI fires 3X every revolution.
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