Husqvarna 128LD Trimmer Piston Question

JBtoro

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Am rebuilding a 128LD. Received the OEM kit from seller and noticed that the piston has different openings where the piston pin affixes Notice the arch on one side versus no arch on the other. The scored piston that I am replacing has no such arch. Is this critical when inserting the piston into the jug; ie, does the arch go to the intake or the exhaust side? Anyone have any experience with this?

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bertsmobile1

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The arch is there as an aid to removing the gudgeon pin retaining clip
The ones without the arch use a clip with a tang on it so it can be removed
The acrh ones use a plain clip with no tank so you have to use the arch to get under the clip to remove it.
 

JBtoro

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The arch is there as an aid to removing the gudgeon pin retaining clip
The ones without the arch use a clip with a tang on it so it can be removed
The acrh ones use a plain clip with no tank so you have to use the arch to get under the clip to remove it.
The retaining clips on the kit I got are identical; both have tangs. Which side gets the arch, the left clutch/shaft side (red dot) or right recoil side (yellow dot) or does it matter?
 

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bertsmobile1

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OK, so there is only the arch on one side of the piston .
In that case I have no idea why it is there unless it lines up with a hole for the fuel pump in the cylinder .
With blue smokes what is drastically important is the ends of the rings do not pass over a port and in particular the exhaust port .
 

JBtoro

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Yeah, I'm thinking that the arch is there to make it easier to get the 2nd clip installed. The 1st clip is easier to install because you can hold the piston in your hand while twisting the clip into its groove. But the 2nd clip must be installed after the rod is attached to the pin, thus it is more finicky to get the clip in place. As far as alignment, I'm just going to make sure the piston is placed so that the ring gap is, as you stressed, is away from the ports. Thanks a bunch.
 
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