w8ye

My Feedback: (16)

Rod,

All the 90T's and 100T's I've been around are made like yours.

Sounds as though your mixtures are way off.

The low speed screws are air bleed screws and work backwards. To screw them out make the mixture more lean and to screw them in make the idle mixture more rich.

The factory setting for the idle mixture screws is half way across the air bleed hole.

When setting the high speed needles, Peak the rpm for each needle and go back and forth a couple times to be sure of the peak. When the peak is found, richen up two or three clicks.

Adjust the low speed the same way except remember the needles work backwards. You should be able to get it down to around 2500 without one jug going out? When you are done with the low speed needles check your transition to high speed. If the engine quits when the throttle is shoved wide open, your idle is too lean. If the engine stumbles and eventually clears itself out and reaches high speed, the idle was too rich.

w8ye

My Feedback: (16)

Marl,
I think your conclusion is correct. The written word still stands on it's own.

rchotrod

Would exhaust temp be a good way to tune the multi cylider engines? Think that would show a lean or rich mixture more accurately for each cylinder?

Just an idea to see if it might make tuning a bit easier.

I do understand the airbleed needles. I didn't know you could actually see the screw in the ports. Will take a look. I will keep adjusting. I am just being very careful to not get too lean too fast.

Thanks for the tips
See ya
Rod

w8ye

My Feedback: (16)

Rod

Exhaust temperature would be a good way to check the mixture at high speed but would not be very accurate at idle. This is really not necessary if you listen carefully

Look at the screw for one side and look on the front (or back) of the carb where the screw would go. There will be a little hole less than 1/8" diameter and you should see the screw in the hole.

I'm not talking about the main carburetor air intakes.

Looking at my 100T from the rear. The air hole for the right cylinder is just under the fuel inlet.

The air hole for the left cylinder is on the front side adjacent to the choke plate.

You may have to shine a flash light in the hole to see the screw?

Wing-Ding

w8ye,

The bearings for the FA-91S just arrived! I used my puller to remove the prop drive washer. Removed the cam assembly. What temperature should I set the oven at for bearing removal? Any tips you can provide at this point would be greatly appreciated. In a previous thread for a Saito 56, the oven temp was 275F and then the crankcase is banged against a board. Is it a similar procedure for the FA-91S? Also, how do I know which way to install the new bearings? Thanks!

Marl

N1EDM

My Feedback: (2)

W8YE,

Thanks for that update... I just thought of something... did you happen to disassemble the engine? If not, I'm wondering if you encountered something that happened to me. I bought a 120 Single from a friend. It sat around for quite a while but was in good shape except for the lower crankcase housing, which I replaced. In the process of doing that, I noticed that the pushrods were very sticky. It took a lot of work to free them up - nothing difficult, just time consuming. I'm wondering if this could be happening to your 72 as well? Just a thought,

Bob

blw

My Feedback: (3)

Marl,

I know you are right. I just hate seeing someone having the blame shifted on them in these deals.

w8ye

My Feedback: (16)

Bob, nothing was done to the 72 except change the back plate and intake gaskets.

Right off, I don't see sticking lifters as causing it to run rich?

w8ye

My Feedback: (16)

Marl,
the procedure is the same.

On the front bearing you can leave both seals intact.

On the rear bearing remove both shields.

If the rear bearing has a plastic ball cage, this goes towards the front.

To be more accurate about installing the rear bearing, I fit it to the crankshaft first and then stick the assembly down into the crankcase. That way you can get the bearing aligned as straight as possible. I put the front bearing on over the threads of the crankshaft.

Captcrunch44

i just put my finger over the end of the muffler and use presher to prime mine.
crunch

Terry 5

My Feedback: (3)

Hello, Im looking for some help tuning a new Saito 2.20. Its has over a gallon of 20/20 run thru it and turning a 19/8 wood prop at 7600 rpm. The problem is that ever time I throttle back the engine stumbles and quits with a bit of a cough from the carb. I have the LS at about even with throttle arm and have gone a bit both ways but cant get this thing to idle right. It will stay on at about 2700 but its imposible to keep it still on the ground. Any help would be appreciated.

Wing-Ding

Well I got the new bearings installed in the FA-91S! I used to rebuild cooling turbines for F14's many years ago so I thought I'd try something that we used to do for pressing turbine wheels onto shafts:

I put the rear bearing on the crankshaft and stuck it in the refrigerator. I then put the housing in the oven at 275 for about twenty minutes. Took the shaft out of the fridge and then the housing out of the oven. The rear bearing literally fell into place. I held it there until everything was near thermal equilibrium. And Voila! Rear bearing installed!

The front bearing wasn't so easy. I tried the same method, but the bearing only went half way before getting stuck. So I got a 9/16" socket that would contact only the outer race but not so large that it would get stuck in the housing front bearing bore. Heated the whole thing at 275 for about 35 minutes, and then ran it out to the garage. Since I don't have an arbor press, I used my drill press and socket to press the front bearing the rest of the way in. Fortunately, it didn't take much force.

I hope I did everything right. The shaft spins very smoothly now (not like before when it was seriously grinding and actually stopping in places). I put the prop drive washer back on and everything spins smoothly, plus there doesn't seem to be any axial play. I'm assuming that's good.

Well, what do you think for my first time? BTW, now that I've cleaned all the parts, what oil do you recommend when I reassemble? I'm thinking ARO (ATF). Thanks for all of the advice.

Marl

blw

My Feedback: (3)

Marl,

That's a good way to get the bearings out (heat) and get them back in. Freezing works well like you found out. Glad you got them back in. Just about any oil will work well for reassembly. Even glow fuel works. Moly grease will work too.

boogermancan

wing-ding the cold and hot works real well i used the trick to put the ring on the chunk of a 12 bolt chevy works ever time.
good to hear your makeing out well with the motor i hope it has many flights in what ever you putt it in

Wing-Ding

Thanks Boogermancan. I got the cam assembly reinstalled and valve timing set. Now just waiting for my new ring and connecting rod to show up. Maybe even have installed on my WM Super Chipmunk for the weekend. I meant to ask- I lost track of which way the connecting rod goes onto the shaft. There's a dot on one side. Do you know which way it's supposed to go? Thanks much.

Marl

boogermancan

something about the chaffer if i rember not sure with way w8ye poster witch way to putt it its back a fue pages um <<<The "DOT" goes where ever it wants to. Ignore it.

What's important is the chamfer in the ID of the big end of the rod. This chamfer goes towards the crank.

_____________________________

I've attended the CutFinger Institute of DirtNap University for years but never did graduate....

Club Saito Member #7
Original AMA #31261 >>>

Wing-Ding

That makes sense to me that the chamfer would be oriented toward the crank (as you said). It looks like there is a small radius where the crank journal attaches to the counter weight and the chamfer accommodates that radius. I also noticed on my engine that the dot is on the same side as the chamfer.

boogermancan

um that was quote from W8YE so as he has said not sure how the quote works was not to long ago i figered how to post a pic but any how a test of a quote lol some time one must putt finger in prop to see how bad it will hurt

w8ye

My Feedback: (16)

You cannot depend on which side the DOT is on as Boogermancan says. Look for the chamfer on the big end bore

Hobbsy

My Feedback: (102)

Terry, my guess is that the LowSpeed needle is set too rich and the engine is stalling and running backwards a few revolutions and you're hearing air being pumped out through the carb. re-set the LS needle for best idle and transition with the HighSpeed needle at absolute peak. Then set the HS needle to your normal flying setting.

Terry 5

My Feedback: (3)

Yes it has been running backwards when it stops.

N1EDM

My Feedback: (2)

Wing-Ding,

Before you assembled the engines (after installing the bearings), if the crankshaft counterweight would drop to BDC of its own weight, I would say that you've done everything that you should.

I used the same technique to install bearings into my rebuilt Satio 1.20. The crank worked beautifully.

Bob

boogermancan

Terry 5
last thing you want is the motor to start runing backwards in flight. oh my what a flight that will be

BobReeves

Wow, don't visit this site very often as I fly control line and we have several other forums focused on CL only. What a great thread, wished I had time to read it all. Guess I could qualify as a club member I have 1-30, 3-40a's, 2-56's and 2-62's. I love the Saitos and have all but given up running two strokes, can't for the life of me understand why they quit importing the 40a, in the CL world it is one of the best 40's ever.

We typically replace the carb with a fixed venturi along with some means to adjust the choke area for fine tuning. What we look for is consistency, we don't want the engine to change one bit from the time it starts till it quits. Have found some of the carb barrels leak air resulting in random RPM changes so we eliminate it. I run YS 20-20 with an 11-7 on the 40 at about 8200 and 13-7.5 on the 56 at around 7900 to 8000. We have also discovered the Saitos run best side mounted, probably has something to do with us flying around in circles. Haven't ran either 62 yet but looking forward to it.

Anyway, just wanted to say hi and if it hasn't already been said let you guys know Saitos are not used just for RC

w8ye

My Feedback: (16)

Welcome to the thread Bob.

You have a lot of Saito info to share with us. Come back soon and feel free to jump in anytime.