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Broken pushrod on lightly used Saito 100

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Old 12-16-2012, 05:53 PM
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skrez
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Default Broken pushrod on lightly used Saito 100

Hi Guys,
I purchased a brand new Saito 100 in 2007 , broke it in according to the manual and flown it less that 12 times. I also set the valve clearance to .002-.003 after break-in . I pulled the vavle cover off today to do my winter maintance and found the broken pushrod. What would cause this, is this common on 4-strokes? Guess I will have to send it to horizon for repair.
thanks,
Frank
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Old 12-16-2012, 05:58 PM
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Default RE: Broken pushrod on lightly used Saito 100

A pushrod should be easy to order and install.
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Old 12-16-2012, 06:02 PM
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Ernie Misner
 
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Default RE: Broken pushrod on lightly used Saito 100

Hobbsy, can you just pull the valve cover and drop the pushrod right down in. That easy?
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Old 12-16-2012, 06:13 PM
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Default RE: Broken pushrod on lightly used Saito 100

I think that if you press the valve spring down the short end of the rocker will move up and away just enough. I'll try it on an .80 tomorrow.
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Old 12-16-2012, 06:31 PM
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Default RE: Broken pushrod on lightly used Saito 100

Iwould like to know what tach readings you are getting. I suspect it may be overrevving if its underpropped. It causes a lot of strain on the valvetrain.
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Old 12-16-2012, 06:38 PM
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Default RE: Broken pushrod on lightly used Saito 100

I was using a 14X8 apc taching at around 9000 rpm
Frank
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Old 12-16-2012, 06:47 PM
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Default RE: Broken pushrod on lightly used Saito 100

That isn't close to over reving on the ground. Saito says 11,000 rpm, so figure around 10,000 on the ground. It's a judgement call since we don't know how much it unloads in the air. I use about a thousand rpm for headroom.

I'm curious to see if Dave can slip one in on his 80.
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Old 12-16-2012, 07:13 PM
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Default RE: Broken pushrod on lightly used Saito 100

Ditto
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Old 12-16-2012, 08:14 PM
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Default RE: Broken pushrod on lightly used Saito 100

Well, You can slip the pushrod out of the socket by pushing down on the spring but the pushrod will not come up past the side of the rocker arm to get it out or the new one in.

I just remove the carb and back plate, then lift the cylinder/piston/rod off. Then install the new puchrod in the tube and stick it all back together.
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Old 12-16-2012, 08:21 PM
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Default RE: Broken pushrod on lightly used Saito 100

I think I saw specs on an OS buggy 4-stroke engine that turned 20,000 rpms a few years back. Don't think I was dreaming. How did they do that?
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Old 12-16-2012, 09:24 PM
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Default RE: Broken pushrod on lightly used Saito 100

Cant you just remove the rocker shaft and take off the rocker arm?
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Old 12-16-2012, 10:19 PM
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Default RE: Broken pushrod on lightly used Saito 100


Quote:
ORIGINAL: jeffie8696

Cant you just remove the rocker shaft and take off the rocker arm?




Yeah....it's a lot easier to do it that way...
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Old 12-17-2012, 12:18 AM
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Default RE: Broken pushrod on lightly used Saito 100

Many times the rocker shaft pivot screws don't want to come out.
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Old 12-17-2012, 03:48 AM
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Default RE: Broken pushrod on lightly used Saito 100

Just remove the rocker pivot shaft and replace the pushrod. Literally 5 minutes. and the pushrods are super low cost.
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Old 12-17-2012, 04:18 AM
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Default RE: Broken pushrod on lightly used Saito 100

I'm with w8ye in that it takes a real good flatblade screwdriver,a bit of muscle and a lot of luck to unlock the rocker pivot arm screw
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Old 12-17-2012, 04:50 AM
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Default RE: Broken pushrod on lightly used Saito 100


Quote:
ORIGINAL: Old Fart

I'm with w8ye in that it takes a real good flatblade screwdriver,a bit of muscle and a lot of luck to unlock the rocker pivot arm screw
That makes 3 . Much easier to lift the barrel , I have found . Cheers the pope
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Old 12-17-2012, 05:43 AM
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Default RE: Broken pushrod on lightly used Saito 100

There is a way, this is a .65, so if the 1.00 pushrod is not too fat.

http://www.horizonhobby.com/products...-qq-SAIE100#t4
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Old 12-17-2012, 06:02 AM
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Default RE: Broken pushrod on lightly used Saito 100

The rocker arm and pushrod are the same on the 100 and the 65
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Old 12-17-2012, 06:04 AM
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Default RE: Broken pushrod on lightly used Saito 100

Jim, I tried to find the Alpha Numeric chart at Horizon.com but like the rest of their site, I couldn't find it.
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Old 12-17-2012, 07:11 AM
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Default RE: Broken pushrod on lightly used Saito 100

http://www.horizonhobby.com/article/...th-alpha-codes
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Old 12-17-2012, 10:24 AM
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Default RE: Broken pushrod on lightly used Saito 100

If you do-it-yourself, does that kill the warranty? I know Frank's is already out of warranty, but I am just curious.
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Old 12-17-2012, 10:50 AM
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Default RE: Broken pushrod on lightly used Saito 100

I think its going to turn out that a valve was stuck open. Horizon is beyond fair with warranty issues but I can't answer that directly.
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Old 12-17-2012, 10:51 AM
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Default RE: Broken pushrod on lightly used Saito 100

Thanks Barry, I added that to me Favorites
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Old 12-17-2012, 11:02 AM
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Default RE: Broken pushrod on lightly used Saito 100

Well guys, thank you for all your help. I have been away from glow planes for a few years and flying electric planes and EDF`s. so I forgot allot. As it turns out , it seems that the rod was just stuck in the down position and after I put some air tool oil in the valve areas now it looks fine. I reset the valve clearance to .003 and everthing seems to be normal with the movment on the valves and rods. But I wondering if I should pull the rod out anyway to see if it is bent? I`m not sure why it would have stuck in the down position in the 1st place?
Frank
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Old 12-17-2012, 11:05 AM
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Default RE: Broken pushrod on lightly used Saito 100

More than likely the valve was stuck and not the pushrod.
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