Husqvarna 576xp port work

[Chainsaw Jim]

I had to install a new piston in my 576xp so I decided to go through it to eliminate a few casting burrs and case pattern mismatch.
I got a little ahead of myself and started grinding before taking any pics.
The intake had some casting burrs inside the two outer holes. I'm not sure there was much restriction there due to the tiny intake boot anyways. But I cleaned that up a bit anyways...


Then I moved on to the lower transfers..




With the base gasket removed the squish was too tight. I shaved the little band off the edge and that brought the squish to a nice and cozy .025. I didn't actually take anything other than the little band around the edge to even out the area. If I was to shave it any more to make it cleaner then I'd have to cut the base to lower the jug. Which this particular saw actually had an uneven base. It wobbled on the bare case and I had to take about 0.002 from each side before it would sit flat. Very poor quality control from the factory.



Now for the exhaust...

 

[Ironworker]

Nice work, did you raise the exuast any.

 

[Chainsaw Jim]

Thanks.
I raised it just over a degree.
EDIT: that doesn't mean it changed the timing any. That amount I raised it only compensated for the gasket I removed. I'd say it is still close enough to stock numbers to be called stock.

 

[Chainsaw Jim]

Putting this beast back together with oem piston...




Muffler mod was nothing spectacular. Just a regular aftermarket screen and shroud, and not the best choice. I just used what I had on hand. I would much rather braise a better one on and paint the muffler.



Larger spikes and now it's ready for a set of teeth it can eat with....

 

[Chainsaw Jim]

This first video is with the 13,300 blue limited coil.



This second video is with the black unlimited coil.

 

[Chainsaw Jim]

After running this thing I'm really wondering if and when a 590xp and 595xp are coming. They would be insane if the same upgrade can be achieved.
Stock versus stock, I think the 372xpw 75cc is a few steps behind the 576xp. I really wish I had an ms461 to compare because I think it might thump that one too.

 

[sfg.Foley]

Hi,

where do you get the black coil? Will a 372 XP coil fit too?

Lg

 

[BGE541]

Hi,

where do you get the black coil? Will a 372 XP coil fit too?

Lg

You can get an aftermarket coil for cheep on fleabay. There two allens that hold the coil in place, then space between the flywheel pickup .005" or the thickness of a business card.

 

[sfg.Foley]

Thank you

 

[Big_Wood]

i ported my 576 much the same but at first didn't raise the exhaust. also did some intake work even though there ain't much to work with. they can use all the help they can get on the intake. squish was .026 so i left the gasket in. found a stumpy thread and saw a post mdavlee made on them needing more blow down so decided to give it a go. raised the exhaust and wholey **** did it wake up. improved torque and i haven't done a compression test but it feels no different then before. what's your squish at? mine would have been at .009 had i deleted the gasket. i see dirko or something squeezing out. if it's dirko do yours and anyone going in after you a favour and stop lol it's the messiest the work with and shittiest to clean up out of anything i have ever used.

 

[Chainsaw Jim]

Permatex for aluminum applications. I squeeze a dab down inside the corner of a sandwich baggie and tie it off. Then I cut a tiny nip off the corner so I can pipe it like a pastry chef. It leaves a nice little thin line that leaves no excess amount to cause problems.
my squish is right at .022, I removed the little edge you see around the squish band to allow removal of the gasket. This can actually be done by hand since there are no measurements to follow. Some glue sand paper to a piston and use it as a sanding block to remove that little lip. If you're careful enough with a steady hand, you can shave it with a hand chisel and get it perfect.

 

[TreeswingerPerth]

Looks and sounds great , nice work . Makes me want to get into my 575 xp !!

 

[Big_Wood]

Permatex for aluminum applications. I squeeze a dab down inside the corner of a sandwich baggie and tie it off. Then I cut a tiny nip off the corner so I can pipe it like a pastry chef. It leaves a nice little thin line that leaves no excess amount to cause problems.
my squish is right at .022, I removed the little edge you see around the squish band to allow removal of the gasket. This can actually be done by hand since there are no measurements to follow. Some glue sand paper to a piston and use it as a sanding block to remove that little lip. If you're careful enough with a steady hand, you can shave it with a hand chisel and get it perfect.

i was fortunate in the fact that my 576AT had a flawless squish band. no steps or nothing and quite flat compared to most. there was no little edge to remove. just a perfectly shaped band and .026 stock with a gasket to boot. i have another 576 cylinder here and the squish is terrible compared to the one on the runner. the casting in all the ports is also alot more rough. both cylinders made by mahle. you must be refering to the step on the outer edge of the squish band? my 562 was like that. i cleaned it up and got the squish set at .019. with an .017 gasket.

 

[Big_Wood]

Your saw does sound really beastly compared to how mine did at first. My muffler was done by a builder on here and I was not impressed with it at all. screws for deflector kept vibrating lose every 3-6 tanks and sounded like a raspy pingy POS. I redid it myself and it is much quieter, sounds better, fully screened, and does the same job. now nothing comes lose. so much better. worrying about screws coming lose while falling sucks!. the worst part is knowing they will in fact loosen. it's just a matter of when lol no amount of loctite could hold them! the added screen for the pipe port has a acorn nut welded on the inside and a screen rack welded so it holds the screen secure and tight against the pipe. i'm all ****ed up over it. i hate how it handles like a gutshot seagull compared to a 372 but i like how it will easily outrun a stock 390 after porting. mines up on the hill right now stashed in a hollowed out stump in -10 weather. should fire right up in the morning lol.

 

[Chainsaw Jim]

Hi,

where do you get the black coil? Will a 372 XP coil fit too?

Lg

Yes a 372 coil will fit. Mine is from a 357xp. The smaller saws have a shorter spark plug wire by about a half inch, so you have to bypass the little plastic arm on the air injection shroud for it to reach the plug.

 

[Big_Wood]

Yes a 372 coil will fit. Mine is from a 357xp. The smaller saws have a shorter spark plug wire by about a half inch, so you have to bypass the little plastic arm on the air injection shroud for it to reach the plug.

or replace the wire all together. mine has a coil limited to 13,300 but i'm really not worried about it. i think AT will make it perform regardless. it does still hammer off the limiter while limbing despite the AT. owell, when it dies it dies. i can deal with the limiter hammering. i don't think there is any other option for coils on AT saws?

 

[Chainsaw Jim]

or replace the wire all together. mine has a coil limited to 13,300 but i'm really not worried about it. i think AT will make it perform regardless. it does still hammer off the limiter while limiting despite the AT. owell, when it dies it dies. i can deal with the limiter hammering. i don't think there is any other option for coils on AT saws?

I do believe you can put the unlimited coil on the AT and get the same results as manual tune. I'm also thinking auto tune will probably outrun the manual tune with the unlimited coil since the carb will maintain tune better throughout the entire rpm range.
Then again it may be an entire different flywheel and I haven't checked into it yet.

Edit: I just checked and the flywheel is just the regular heated handle flywheel they've been making before the 576at came out. Any unlimited coil should work.

 

[Big_Wood]

I do believe you can put the unlimited coil on the AT and get the same results as manual tune. I'm also thinking auto tune will probably outrun the manual tune with the unlimited coil since the carb will maintain tune better throughout the entire rpm range.
Then again it may be an entire different flywheel and I haven't checked into it yet.

i'm not sure on it either but i do have a black coil to try when i get time. i'm not exactly sure if the gen 1 AT on the 576 is feedback or not but i'd imagine it would have to be? the coil looks identical to a 372 coil but it is grey. i have seen 13,300 husky coils before but they were blue. maybe the grey ones are for AT? i haven't done any testing with this model really. all i know is a like the way it runs even with the 13,300 coil. i'd kill for the same running saw in a 372 chassis though.

 

[Chainsaw Jim]

i'm not sure on it either but i do have a black coil to try when i get time. i'm not exactly sure if the gen 1 AT on the 576 is feedback or not but i'd imagine it would have to be? the coil looks identical to a 372 coil but it is grey. i have seen 13,300 husky coils before but they were blue. maybe the grey ones are for AT? i haven't done any testing with this model really. all i know is a like the way it runs even with the 13,300 coil. i'd kill for the same running saw in a 372 chassis though.

The 576xp auto tune lists the same coil as the 570 and 576xp. Based on that information it will work for sure.

 

[Big_Wood]

The 576xp auto tune lists the same coil as the 570 and 576xp. Based on that information it will work for sure.

if i can fit an unlimited coil on an AT saw to do the work i do i will be tickled absolutely ****'n pink. raw pink actually! will have to pull it off the hill in a day or so to try it. even if only to rid myself of that limiter hammering while limbing. even if it's realy not that bad.