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Old Jan 17, 2014, 07:23 AM
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Saito FA125 A Tappet adjustment

Hi,

Just a quick question. I have recently bought a Saito FA 125 4 Stroke engine. I was reading the instructions and it mentions adjusting the tappets after about 10 flights, is this what most people do on four strokes. I have the spacer included in the engine equipment, is this a tricky process? what is the best way to go about doing this once I have the rocker covers off?
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Old Jan 17, 2014, 10:14 AM
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Barry, its a straight forward process, place the engine at TDC on the compression stroke. Loosen the lock nut on the rocker, then adjust the clearance until the feeler will just slide in and out with a little drag. You're going to get recommendations to use everything from Saran Wrap to Purple Wallpaper for a gauge. Just use the provided gauge and the engine will run perfectly.. Honest
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Old Jan 17, 2014, 06:39 PM
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Quote:
Originally Posted by Barryrobinsonuk View Post
Hi,

Just a quick question. I have recently bought a Saito FA 125 4 Stroke engine. I was reading the instructions and it mentions adjusting the tappets after about 10 flights, is this what most people do on four strokes. I have the spacer included in the engine equipment, is this a tricky process? what is the best way to go about doing this once I have the rocker covers off?
Quote:
Originally Posted by I TOBOR View Post
Barry, its a straight forward process, place the engine at TDC on the compression stroke. Loosen the lock nut on the rocker, then adjust the clearance until the feeler will just slide in and out with a little drag. You're going to get recommendations to use everything from Saran Wrap to Purple Wallpaper for a gauge. Just use the provided gauge and the engine will run perfectly.. Honest
The Saito spec is .03mm to .1mm. That's .0012" to .0039". The supplied gauge will only tell you when you are @ the maximum spec. I use a .0015" gauge.

The gap will open up by .002" after the engine warms. If you set them @ .0039" cold, the gap will be .0059" hot.

To find TDC, rotate the crank until you see the exhuast rocker just closing W/the intake just opening. Rotate the crank 360 to got to TDC compression. Now you can adjust the lash.
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Old Jan 18, 2014, 05:33 AM
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Thanks for the help guys, much appreciated. I'll give it a whirl when I have done 10 flights or so.
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Old Jan 18, 2014, 07:37 AM
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I set them after break in and then check them twice a year and lube the rockers with STP Power Steering fluid. The stuff is both tenacious and slick. They will seldom need adjusting.
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Old Jan 18, 2014, 08:22 AM
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I will always prefer the method of adjusting the clearance of each of the valves separately, when the tappet is on the middle of this cam's base circle; i.e. 360 of crankshaft rotation from maximum lift.
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Old Jan 18, 2014, 08:49 AM
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Originally Posted by DarZeelon View Post
I will always prefer the method of adjusting the clearance of each of the valves separately, when the tappet is on the middle of this cam's base circle; i.e. 360 of crankshaft rotation from maximum lift.
When the engine is on TDC of the compression stroke, the tappets will be on the "base circle" of the lobe.

Whether it is "in the middle or not is moot. You're just making things more complicated than they need be.
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Old Jan 18, 2014, 01:26 PM
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SrTM,


We've had this discussion before; and assuming the cam's base-circle truly is concentric with the camshaft; then as you suggested, *any* location on it (the base-circle) is as good as any other.

But since I have seen cams that were ground off-center (given, in full-size camshafts), I selected not make such an assumption and thus I act accordingly.

This is MY preference!
And no, I do not find it any more complicated and takes just me a couple of minutes longer than the 'customary' method, of adjusting both valves in one go.
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Old Jan 18, 2014, 01:50 PM
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Originally Posted by DarZeelon View Post
SrTM,


We've had this discussion before; and assuming the cam's base-circle truly is concentric with the camshaft; then as you suggested, *any* location on it (the base-circle) is as good as any other.

But since I have seen cams that were ground off-center (given, in full-size camshafts), I selected not make such an assumption and thus I act accordingly.

This is MY preference!
And no, I do not find it any more complicated and takes just me a couple of minutes longer than the 'customary' method, of adjusting both valves in one go.
And you use a degree wheel to determine maximum lift then rotate the crank 360 to get to the opposite side of the lobe?
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Old Jan 18, 2014, 02:02 PM
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No, Sr.


I do it by visually observing the rocker I am about to adjust the lash on.

Yes, I agree it is not as accurate as determining max-lift with a dial-gauge...
But if the cam itself has any degree of asymmetry ground into it, the middle of the base-circle will be somewhat off diametrically opposite max-lift anyway...

But it will not be 45-55 off, as it is when adjusting both at once...
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Old Jan 19, 2014, 03:49 PM
Zor
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Adjusting tools

Hello,

This posting is for the general reader to illustrate the tools supplied with the FA125a to adjust the valve clearances.

The small strip was measured with a precision micrometer reading to 0.0001 inch ( one tenth of one thusand of an inch ).

This little strip is supplied to be used as a gap when adjusting the valves.

Zor
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Old Jan 19, 2014, 04:58 PM
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Originally Posted by Zor View Post
Hello,

This posting is for the general reader to illustrate the tools supplied with the FA125a to adjust the valve clearances.

The small strip was measured with a precision micrometer reading to 0.0001 inch ( one tenth of one thusand of an inch ).

This little strip is supplied to be used as a gap when adjusting the valves.

Zor
I don't know where you got a strip that measures .00001". The one supplied W/the engine is .1mm which is .0039"

The cellophane on a cigarette pack measures .001" think. You're telling me you haver a metal strip that measures 1/10 of that?
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Old Jan 19, 2014, 05:37 PM
Zor
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Originally Posted by SrTelemaster View Post

I don't know where you got a strip that measures .00001". The one supplied W/the engine is .1mm which is .0039"

The cellophane on a cigarette pack measures .001" think. You're telling me you haver a metal strip that measures 1/10 of that?
Telemaster,

I wonder how you got the .00001 in your post above.
I do not have a strip that measure 0.00001 and I did not write that.

Zor
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Old Jan 20, 2014, 02:16 AM
I convince things to work
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Originally Posted by Zor View Post
Telemaster,

I wonder how you got the .00001 in your post above.
I do not have a strip that measure 0.00001 and I did not write that.

Zor
Clerical error....

you DID state .0001 inch, and Sr Telemaster DID mention cellophane being .001 inch and a factor 10 between that and your stated thickness.... So either you, or SrTM typed one "0" more or less than intended.... Never mind that....

And yes, since for example an OS has a valve lash between 0.04 and 0.1 mm, which is between 15 and 40 times thicker than you claim the strip to be, I do NOT believe that your feeler gauge is 0.0001 inch thick....

Brgds, Bert
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Old Jan 20, 2014, 07:20 AM
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Quote:
Originally Posted by Zor View Post
Telemaster,

I wonder how you got the .00001 in your post above.
I do not have a strip that measure 0.00001 and I did not write that.

Zor
Read the quote of your post.

The sheet that accompnaies the tools in the picture is listed a being "0.1t" which is in all likelyhood 0.1mm which is .0039".
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