sundancer007

I just installed new bearings in my Saito 125. What method is used to retime engine?? I know the cam location to TDC. Just need explanation on how to hold my tongue just right

N1EDM

My Feedback: (2)

Hopefully this might be the last word on ARO... I remember a 'recipe' used by Clarence Lee, and I've been using it for years now. It's 50% ATF and 50% Air Tool Oil (I use a special Marvel Mystery Oil air tool oil - not the 'regular' MMO)

Just dropping in my $.02

And I've been running a Saito .56 in my Twist 40 as a 'Sport' plane. Pretty good power. I think that the .65 will work out fine with proper balance. Again, just another $.02

Bob

happypappy

My Feedback: (10)

Need to replace the front bearing at least in a Saito 56. How difficult is it? Do I need special tools to pull the bearing(s)? I have the replacement bearings and a gasket set already.

w8ye

My Feedback: (16)

The front bearing is the last thing to come out so you may as well change both bearings

You will need a puller device to get the prop hub off. Some metric Hex wrenches will be needed

You will need feeler gauges to set the valves but could get by with the one that came with the engine.

w8ye

My Feedback: (16)

The engine crankcase is heated in the oven to 275 for 20 min and the back of the crank case is banged against a board to shake the rear bearing out. The crankcase has to be heated again to get the front bearing out but you will need a dowel to knock the front bearing out.

happypappy

My Feedback: (10)

Same procedure to get them back in?

w8ye

My Feedback: (16)

I put the rear bearing all the way on the crank then stick the assembly up inside the crankcase. I then put the front bearing on the front of the crank. I pull it together with the prop driver and retainer parts. It helps to have the crank case hot.

Cam timing. The mark on the cam goes straight down when the piston is at top dead center.

Push rods have a little end that goes to the top but you can use this little end to stick in the oil hole of the cam down through the intake lifter bore to hold the cam in the correct position for installation on the crankcase.

The gasket under the cam box is import. Be sure and save the old one when you remove the cam box at disassembly.

Garthwood

w8ye.................v.g. explanation. I have never disassembled a 4 stroke/2 stroke, I heard, prior to putting the new bearings back into the crankcase that you can put the bearings into the freezer, the opposite will happen as to heating. This is instead of heating the crankcase again. The bearings should slide in easily.

Any comments to the above ?. I am not an expert, you guys have been doing this for a long time. The removal of the bearing from the crankcase by heating I do know, but the installation I'm not sure.

Charles.

w8ye

My Feedback: (16)

I've at least tried all the combinations.

A little physics here.... The coefficient of expansion of aluminum is 50% greater than the rate for steel. Therefore.....

It is much more effective to change the temperature of the aluminum than it is the steel.

Garthwood

w8ye...................thanks. I knew about the expansion of aluminum and steel, but the freezing part I was not so sure. Is the pulling of the prop hub done prior to the heating process ?.

Charles.

w8ye

My Feedback: (16)

YES. You have to get the prop hub out of the way before you begin to remove the crank.

The bearing seperator and puller I have in the picture can be rather expensive in some auto parts stores but are rather cheap at places like Harbor Freight.

Though not usually the case on the 56, sometimes you have to heat up the prop driver as you are pulling on it with the puller to get the thing to snap loose?

Some people use their Monocoat gun to heat up the parts.

Heat transfer is also quicker in aluminum than steel.

Garthwood

w8ye............thank you for your explanation.

charles.

w8ye

My Feedback: (16)

CHEAP PULLERS

Bearing separator only

http://www.harborfreight.com/cpi/cta...temnumber=7343

Complete separator - puller set but expensive

http://www.harborfreight.com/cpi/cta...emnumber=93980

Inexpensive puller that will work with separator

http://www.harborfreight.com/cpi/cta...emnumber=37714

Combination 2 or 3 jaw universal puller

http://www.harborfreight.com/cpi/cta...emnumber=45977

alfredbmor

What is the working heat range of a regular Saito engine? What temp. is considered overheating?

w8ye

My Feedback: (16)

You start getting much above 300 F on the exhaust side of the head, you'll be getting there.

RVM

How does this fuel (40% nitro) work in our Saitos? I'm thinking of trying it in my .82.

sundancer007

40%nitro fuel = 40% less bearing life.

w8ye

My Feedback: (16)

There's a point of diminishing returns and the cut-off is at 30%

happypappy

My Feedback: (10)

Thanks for the information on the 56. I have all the pullers here so may tackle it tonight.

alfredbmor

In the range between 250 and 300 could we say that is safe to run our engines? What is the most common or the ideal top heating?

w8ye

My Feedback: (16)

I like to keep them as cool as I can.

I consider them hot if you can smell them and they are smoking when they quit. I usually feel of the intake side of the head with my finger to get a relative measure of how hot the engine is.

RVM

That's kinda what I thought. Thanks!

RVM

Is there any real benefit to enlarging the holes in the muffler baffle, or simply removing it altogether?

w8ye

My Feedback: (16)

You would be hard pressed to determine an improvement in performance. Four strokes are not as sensitive to exhaust back pressure as two strokes. You can take the muffler off and gain a couple hundred rpm.

Garthwood

w8ye..............thanks for the links, you think the $12.99 one will be more than required. Of all those you've listed, which one do you think will do the job for just removing bearings etc.... , The more expensive one comes with a number of items, are all thoses part pieces required if one is just removing bearings ?. In one of your pictures you show a seperator and puller, I don't see the puller in these kits.