Kostas1

In some days i will be a proud owner of a SAITO fa-180GK.....

GaGeeBees

My Feedback: (23)

I've got a pair of .56's and they are great little engines but my favorite by far is the 2.70. I have four of them flying at the moment and have owned three others.

mike109

G'day The early Saitos (and OS engines too) had cams which were very conservative. They gave low lift and short duration and as a result the engines were not very powerful but were very sweet and easy engines to run. I had a Saito 45 Mk II which had a low lift cam. It was a pleasant engine to run but had very little power - not enough to fly my Kadet Senior.

I replaced the cam with the "high lift" cam from a 56. You can easily see the difference in the shape of the cams (sadly, I don't have one to photograph) but if you ever see an early cam and a more recent one side by side, the difference is very obvious. The early cam has quite low pointed lobes, the later cam has taller, broader lobes.

The old 45 with the "new high lift" cam is quite powerful. It is at least as good as the later 45s are though not quite as good as my 56.

Mike in Oz

Hobbsy

My Feedback: (102)

Early on in his racing career Ed Eskendarian discovered that you could take advantage of the overlap between the exhaust stroke and the intake stroke by tuning the intake track and the exhaust header. Using the momentum of the exhaust "slug" to create a partial vacuum behind it and having both valves open simultaneously you could trick the intake to start flowing sooner, then by keeping the intake vavle open for the early part of the compression stroke you could use the intake "slugs" momentum to keep air and fuel flowing after the piston started upward on the compression stroke. That's why when you look at where one our engines intake valve closes the crank is at about the 7:00 or even close to the 8:00 position.

ED excercised a little imagination and called it the Isky five cycle cam.

Hobbsy

My Feedback: (102)

Typical valve timing for Saitos

Picture #1 is where the intake valve opens even though the piston is still rising on the exhaust stroke, both valves are open between the black marks.

Picture #2 is the end of the exaust stroke

Picture #3 is the beginning of the compression stroke, the intake valve has been open all this time since picture #1

Picture #4 is the beginning of the exhaust stroke.

If more detailed splainin is needed just holler.

gkamysz

My Feedback: (19)

Was it really Iskenderian that developed this concept? Regardless. This has no meaning in model engines as neither intake, nor exhaust is tuned. The power improvement due to increased duration is there, but it's because the valves are simply more open when needed.

Hobbsy

My Feedback: (102)

Even a stone stock engine is in a state of tune. When discussing engines whether two stroke or four stroke we speak of them as being in a milder or wilder state of tune when comparing to other engines. The statement definitely has relavency here..

blw

My Feedback: (3)

Of course it is tuned to some degree or purpose....

gkamysz

My Feedback: (19)

There is no "tuning" of intake or exhaust in model four strokes. The are made to fit inside models and have light weight and low cost. They are simply not long enough for the gas flow pressure pulses to occur when required to have the desired effect. The size limitations generally preclude the use of 12"+ long intakes and usually exhausts. I hope to investigate tuned exhaust on model four strokes this year. Either intake or exhaust tract can be tuned, or both.

Tuned to the extent that there was some design involved, yes. But, not tuned to The large overlap still helps engines without tuned passages, because the valve allow more exhaust to exit and intake to begin flowing as soon as possible. If late intake closing increases power it's because the cylinder pressure has not equalized with atmospheric at BDC.

earlwb

Well, If I remember correctly, YS engines having some Hatori like canister systems for the exhaust that were "tuned" to add to the performance.
So I assume that even a 4 stroke engine can benefit from a tuned exhaust. But probably not like a 2 stroke engine can.

N1EDM

My Feedback: (2)

While we're on the subject of cams, I have a very early Saito 120, bought used. I have yet to run it, though it has been cleaned and ready to go.

With all this talk about cams, I wonder if a cam from a later 120 (or even the new 125?) would add anything to the engine?

Any thoughts?

Bob

spaceworm

Would that early Saito 120 be the abc version with the gold rocker covers and airbleed carb? I have one of those and would also be interested in the cam interchangeablity. Mine is also used and I have yet to run it.

Sincerely, Richard

w8ye

My Feedback: (16)

This might be in the
Saito Notes at the top of the page if you look through what Bill Robison says?

N1EDM

My Feedback: (2)

This doesn't have the gold rocker arm covers - they're plain unfinished aluminum. I believe that the carb is an airbleed. It still has a choke on it

Bob

RC Specialties

Greg,

I have to disagree. There may be no way to tune by modifying the timing however, there is a small window to maipulate the exhaust pulse in both 2 stroke and 4 stroke engines to achieve better performance. The 4 stroke is much more forgiving in this regard than two strokes. I am looking forward to your studies on this issue.

Jim

TopZueg

My Feedback: (5)

This may not be the right place but I recently purchased my first Saito. It is a 125 but it is missing the long screw that goes through the muffler and attaches to the cap and whatever else is inside the muffler. I just have a 90 degree header and the main part of the muffler. Does anyone have extra of these parts???? Let me know, thanks.

w8ye

My Feedback: (16)

You normally have to buy the whole muffler

RC Specialties

TopZueg,

I have one on my bench. Send me a PM and we can talk.

Jim

gkamysz

My Feedback: (19)

Jim,

Not sure what you're disagreeing with. I agree that there is room for improvement in 4C exhaust. There is a difference, however, between reducing restriction and taking advantage of the dynamic gas flow.

RC Specialties

Greg,

My apologies, perhaps I misunderstood your point.

Jim

Rudolph Hart

Hello guys still have a problem with the 82 carby.When you run the engine up while standing in front of the tailplane i could feel cold fuel drops hitting my left ankle,the engine is cowled and best i could see was fuel dribbling off the main needle extension.All other fuel lines and connections have been replaced.The brass insert in the carby has a small rubber 'O' ring that seals the main needle,engine is 2 years old and run every weekend.Does anyone have a better exploded diagram of the carby?the manual is very so so.Can you buy o rings seperately? and is there another cause i should look at?

ps have a crash free easter

Jimmy Hoffa

My Feedback: (3)

When I fully tighten the carb bolts on my Saito 1.25 the barrel becomes unmovable. Fortunately, I have a brand new carb available and the barrel remains free when fully tightened. I can see no visible cracks or other damage. It was involved in a crash with the previous owner. Hopefully someone can solve this mystery.

Rudolph Hart

I look forward to see what comes out of your question jim,i have combined crash carby parts with new ones to i think your post says.

earlwb

One of the OS long muffler screws ought to work.
I have used a threaded rod cut off to length before. I just use a nut on each end. Use washers and lockwashers too.

TopZueg

My Feedback: (5)

What does the inside of the muffler can look like, is there a baffle or something else inside. This is my first Saito and never have seen the internal arrangement of there muffler. Is it just a cap with an offset stinger for the exhaust to exit? Thanks for your reply Earlwb.