CrashBurn69

My Feedback: (1)

I was just reading the book on my 82a. The instructions say to let the engine run at 4000 rpm's for break in. Can anyone tell me if this is suposed to be WOT set so rich it will not go over 4000, or can it be 4000 at any throttle setting. This is my first four stroke so I am just learning. Thanks

w8ye

My Feedback: (16)

Seems I remember it saying to run the engine at 4000 with the needle valve at three turns?

It's kinda rich but throttle will be about half way?

Enjoy,

Jim

CrashBurn69

My Feedback: (1)

Thanks. I bought a tach. I just wanted to make sure I did not run it too rich trying to run it WOT at 4000.

w8ye

My Feedback: (16)

I have run some new ones with the throttle wide open and the needle richened to 4000. Didn't seem to hurt anything but fuel consumption at the time? Still have the Saito's and they run great.

Enjoy,

Jim

solafein

Step 4a of my instructions states to open the needle valve 2 1/2 turns out, which means from lightly (I cannot overstress lightly here) seated. Step 7, starting, states to close the throttle to 1/4 - 1/3 open. Step 8 emphasizes that one should NOT exceed 4000 rpm during the first 10 minutes of operation.

I would take it to mean that you should set the needle valve, crack the throttle to 1/4, start it and with the igniter still attached, adjust throttle to run at 3500 for a total of ten minutes.

I usually just set the needle valve for 4000 at WOT for 4 or 5 tanks and consider it good. Acording to the instructions, I am wrong.

My first four stroke, a FA91, broken in my way, has been in three diffrent planes, has had 30 gallons of fuel through it and ran perfect on Sunday, all seven tanks. I'll find out tomorrow morning if it still runs good.

CrashBurn69

My Feedback: (1)

Like I said before, this is my first 4 stroke. If the goal is to heat cycle the internal parts to get them to mate properly for break in, 4000 at WOT has so much fuel in it, I wonder if it gets hot enough. And secondly, at 4000 at WOT all that fuel ontop of the cylinder puts a lot of pressure on the ring and sleeve. It could lead to premature failure. With 2 stroke motors, in cars and planes, its based on a heat cycle. I would think also at 4000 at WOT and all that fuel, it would put more stress on the valves and make them need to be readjusted sooner.

hestvikauto

Hi

Finnally. Last wekend i start to run in my saito 100 in my bench.
High speed needle 5 turns out , primed it and boom here it goes.
2 first tanks on 4000rpm. The next 3 tanks i started to lean it more and more.
My qustion is: When i got from 5 turns to 4 turns the engine stops increasing in rpm. 5 turns out it was very rich. On 4 turns out it stops increasing in rpm. Is this corect?
I tacked it to 9000rpm whith apc 15*6 fuel 20*20

Hobbsy

My Feedback: (102)

It does not say 4,000 at full throttle, it says 1/4 to 1/3 throttle at 4,000, on some Saitos it takes less than 1/4 for 4,000 rpm.

hestvikauto

I know. I didnt use full trottle when it was 5 turns out. Maybe 1/4-1/2.
But after my 4 tank whit very rich running i gave full trottle and started leaning high speed nedle. Only one turn in and it stopped increasing rpm. I imediately backed it 500rpm.

ImacPilot

My Feedback: (95)

I have or have had a 56 72 82 and now the new 125 going on my H9 ShowTime...if your gonna' run a 4 stroke,..then at least run the right one...SAITO......V.Rap

w8ye

My Feedback: (16)

Reality check?

Oh my, It's a wonder those Saito's last anytime at all with such critical break-in instructions? If they are that critical, most, will likely fail early if not broken in to the exact prescribed precedure?

What I'm seeing is people try to get the needles set and then fly them.

Sometimes, the low speed is never set completely?
[hr]
I was over to a guys house the other day and he had a new Saito. He ran one tank at medium throttle with the needle however it was when he took the engine out of the box? The next tank, at his request, I peaked the needles, checked the transition for him. He thanked me and that was the end of the bench running. The engine went into his new plane and the next day he was in the air with it. Probably has ten flights on it now. He is well pleased.

I was over at another field last year. A guy had a brand new, never run 91 in his new plane. He started and contended the engine wouldn't idle very well? It quit. Stupid Saito? I told him about leaning the mixture on the idle. It took a half dozen times of him running it to check the idle and then shutting down to adjust. At least it got some heat cycling? Away into the air he went. Saw the plane last week, still runs great and he is very pleased with his Saito too.
[hr]
If I jumped up and down at the field with all the people not breaking their engines in correctly, they would think I was a hot head nut?

Another true life reality adventure? Just trying to get along with everyone?

These people didn't visit the RCU Engine Forum?

Jim

kevhunt

My Feedback: (4)

Has anyone here ever put a Slimline Pitts type muffler on their Saito? Any adverse effect on performance or other problems???

Kevin

TimC

One morning I went out to visit a field and the only other person there was young pilot flying a Pizazz with a Saito .91. I notice it had a horrible gurgle every time he spooled up. I asked if he had tried to adjust that out with the low speed needle. He coldly informed me that the low speed needle is set by Saito at the factory. He was a pretty good stunt pilot and I watched a bit then went to the store for a cold soda. When I came back, the tail of the Pizazz was sticking out of a trash can.

William Robison

My Feedback: (3)

Reality check (Part II)

A piston ring is seated in the first few seconds of engine running after its installation. This holds from the smallest to the largest of ringed engines, and is dependent on cylinder pressure to force the ring against the bore. Therefore, the initial running should be done at a high power setting.

My way is to allow the engine a few seconds to come up in temperature, then I immediately peak the mixture at full throttle, then right back to idle. For the first few minutes of running the engine goes to full throttle for about five seconds, then back to a rich idle for twenty. This gives me the high cylinder pressure to seat the ring while at full, and then at idle more oil is spread on the working parts.

After these first few minutes I'll go back to full and get about 800 rpm rich drop, then lean the idle a bit but not all the way, and put the engine in a plane. Over the next hour or two I'll slowly lean the idle, and bring the HS closer to peak. After a couple hours total time the engine is all ready for extended high power, and I've been able to fly the fuel through the engine instead of oiling the grass at my house. Or not oiling the grass as much as many do.

Bill.

NM2K

My Feedback: (14)

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In my younger days, like early twenties, it was suggested by my Father that I adopt a practice that he read about in a book somewhere. It stated, "You'll never learn anything with your mouth running all the time", or something like that. I love to talk, so this was a bitter pill to swallow, but I hung in there and learned a few lessons.

We had some older fellows in the club that really knew their s-stuff. Seriously, these guys were pros. But, as time progressed and their age took its toll on them, they drifted away from building and flying and instead became the Engine Police. Shame on you if they thought you knew less than themselves. And just about everyone else did. They would immediately come over to your space while you were setting up and then would begin questioning you on whether you had broken-in your engine properly or not.

I had been flying control line for a decade or so (alone and ignorant) and had never actually intentionally broken-in an engine. I popped them on the model, peaked them out and cussed when they quit from overheating. Eventually the engines would calm down (usually with much less compression) and I would fly them - not knowing any better.

I quickly learned to follow the old guys around and listen to them talk. What an education! Unfortunately, the person they were talking to usually became red-faced after a while of being badgered by these unbendable stalwarts of proper procedure and their Keepers of the Faith attitudes. But it wasn't me they were grilling, so I just listened and learned.

Those two or three older gentlemen put me on the road to enjoying my engines a lot more than I could ever have imagined.

Back then, there were lapped piston engines (meehanite piston and steel sleeve) and ringed engines. No ABC, AAC, ABN, etc., engines at all. Life was simpler.

So what is the point? Engines, even today's engines, demand thought, study and skill to operate properly. Either switch to electric, or accept the idea that it will take a while to become accustomed to glow engines and their requirements. And don't be too hard on the old guys. They are just trying to do what Eons of evolution has programmed them to do. That is to pass along what they have learned to the younger folks - even if it irritates the p - er - potatoes out of them. <G>

No, Jim. This was not directed at you. Weren't you one of the old guys at my field back then?

gjeffers

can anyone confirm that there is not a throttle body spring it the carb of a saito 125 or did i lose mine?
(which i dont thin i did)

William Robison

My Feedback: (3)

Gary:

I can't imagine its not having one. It keeps the barrel from rattling side to side and hammering the stop. Also, it holds the LS needle in proper relation to the spray bar.

Bil.

Hobbsy

My Feedback: (102)

Ed, here is my old 1.50S turning a Mejzlik 16x8 on 10% nitro.

w8ye

My Feedback: (16)

Fortunately, where I normally fly this winter, There are no police. But the other field where I visit, has at least one. He has already told me a thing or two about how "I should have done it". I thanked him and went on about my business.

There are several clubs near my home in Ohio. At two of these the "Police" are usually there. So I have seen them. They do not fly.

I've been trying to keep my mouth shut at the flying field unless I'm asked. But I'm 61. I'm sure a lot of the young flyer's consider me to potentially be a policeman?

Was flying most of the day. I had my Saito 91 on a H9 Super Stick and the other guy, (BLWBLW), had a Saito 56 on a Sig Cavalier.

Enjoy,

Jim

w8ye

My Feedback: (16)

The 125 does have a barrel spring...

http://www.horizonhobby.com/Search/D...i125a90&CatId=

Thunderchild

Velocity Stacks revisited

Will,

I can't seem to find where it was mentioned (perhaps an addition to your wonderful notes?) but could you please advise what type of "O" ring to use with the velocity stacks when I fit them to my Saitos - I've ordered three for my 65, 82 and 91.

Cheers and thanks for the prompt email of your notes. Great stuff!!

Thunderchild

William Robison

My Feedback: (3)

TC:

I never said anything in particular about the o-rings, only that the gap between the carb body and the stack had to be sealed for it to work properly.

I've always been leery of using an o-ring in such a place, my preference is to cut a length of tubing that's a snug fit in diameter and length to go there, and dab some RTV on the outside of it to complete the seal.

What I've been told about the o-rings is someone taking the carb (or complete engine) and the stack to their local hardware store and just picking out one to fit.

My aversion to an o-ring here is for two reasons. One, the tubing will give a much smoother surface inside, the o-ring is either going to have two grooves or a bulge into the air flow, or both. Further, if the o-ring is loose it might not seal well, and it could work its way out of position and go into the carb. If it's clamped tightly, as the oil in the fuel works its way around the o-ring it might get squeezed out and get into the carb. I doubt it would hurt anything mechanically, but it could jam in the throttle barrel and be a fault that was very hard to find. Worse case would be causing a dead stick and still be a bear to find.

Of course you could find an o-ring that was a perfect fit, just lightly clamped, and it would work perfectly.

Let us all know which way you go, and the size of the "Perfect" o-ring if you find it.

Bill.

Thunderchild

Will,

When you say you prefer to use tube, I can't quite picture how you intend it to be fitted. Is it a sleeve arrangement over the outside or is it internal or what?

I must admit, I do like the idea of an O ring if I can be certain it will stay put, but your tube idea intrigues me.


TC

William Robison

My Feedback: (3)

TC:

You will select a tubing diameter that will fit into the recess where the Teflon seal was fittesd for the choke plate, and cut it to length to be a snug fit between the carb body and the flange of the stack. The picture is an old FA-80, the white ring is the Tedflon seal. Its outer diameter will be 11 mm or 7/16" depending on which rack you visit.

And a small o-ring around the outside of the tube would probably make it as good as you can get. I'll try the outside o-ring on my next one.

Bill.

Thunderchild

Ah!!! I see the light.

Thanks Will.

Thunderchild