Husqvarna 55 mod

[RIDE-RED 350r]

That’s what we were planning but I learned from someone much smarter than me that you can’t go very deep on the base before getting into the pulse port passage. So, he’s going to play it safe and just cut the base to tighten the squish. Another thing to keep in mind on this one Joe is that the wrist pin is only 10mm in diameter. That’s 2mm smaller than the 254’s wrist pin.

Ah, I see. Well that sucks he's still going to delete the gasket even getting the base cut. That's one of the perks of cutting the base and squish.

 

[RIDE-RED 350r]

028s is same bore.....
Just saying...

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028 piston a little taller pin to crown?? Scrape up a little more compression? Windowed piston??

 

[tickbitintn]

Can't remember off the top of my head...
028s is domed and windowed...
I can measure them tonight...

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[GoBigBlue1984]

028 super is 46mm and is windowed/domed. With spacers they’ll fit in the open port and make good runners.

 

[tickbitintn]

028 super is 46mm and is windowed/domed. With spacers they’ll fit in the open port and make good runners.

Is the pin different??
Sleeves for pin to make it work?

Can't remember, I know I had an 028s piston set aside for the last 55 I did...
I didn't use it cause I knew the person I was building it for would never tune it or take care of it so it went back mostly stock with just a squish adjustment and minimally porting...


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[XP_Slinger]

028 super is 46mm and is windowed/domed. With spacers they’ll fit in the open port and make good runners.

His 55 Piston measures a hair under 45mm at the crown. How do you squeeze a 46mm piston in it????

 

[tickbitintn]

His 55 Piston measures a hair under 45mm at the crown. How do you squeeze a 46mm piston in it????

Is it a closed port?

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[RIDE-RED 350r]

Yeah, it's a closed port, so it's 45mm.

 

[GoBigBlue1984]

Yessir. I was saying that the 028 super piston is not an option here. If he needed a piston, which I assuming he doesn’t, his options are a 353 piston (with some work) a 254 piston (custom wrist pin) or an alpina 500 (.080-.090) from the base iirc.

I personally prefer the 353 piston. I’ve built a couple this way, open the lowers ala 475, 505 Poulan/jonsered 2077, 2083. This requires grinding the lowers and the piston.

From my experience they run better than the finger ported Closed port.

Small combustion chambers on these saws. Tightly shaped ports.

You can take .050 plus from the base with the spacers I’ve wired from the bottom of donor jugs. Otherwise as has been mentioned earlier, the impulse will not seal.

 

[GoBigBlue1984]

Pop up does very well with these too.

 

[tickbitintn]

Yeah, it's a closed port, so it's 45mm.

Sorry somehow I missed that!!
I built one of those a couple years back...
I believe the only piston available is from lil red Barn...

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[RIDE-RED 350r]

All good Tick, the closed port 55 I overhauled recently threw me for a loop as well. I had no idea the closed and open port 55 had different bore sizes. And you're right, Lil Red Barn is the only supplier of windowed 45mm pistons. I used their piston in the aforementioned saw and all is well so far.

 

[tickbitintn]

I used one of those as well...
Still running as far as I know...
I'm sure I would have heard if it wasn't...
Cut base and squish, was a real good runner.

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[Troylee]

I have a 55 cp that Brad Snelling built. He cut the windows and a .030 popup into a Meteor piston from a 51.

 

[Troylee]

The Husqvarna 254 piston is 45mm and will work with brass bushings made for the wrist pin bores, per Mastermind

 

[Troylee]

 

[Troylee]

 

[Troylee]

50 plus tanks of fuel thru it and still kicking butt. Love this saw.

 

[RIDE-RED 350r]

Not your average 55 I bet!

 

[skidder]

Bet that’s a bad 55 right there!!