Modding a Poulan Pro 475

[Mastermind]

Is the 576 a full circle like the 562?

Yes sir.

 

[Mastermind]

^ I rike dis idea

So do I. Too much goes on in PMs here. We need to post for on this stuff for the newer members.

 

[GoBigBlue1984]

What do you guys think about a series of threads dedicated to one aspect of the engine?

Like a thread on exhaust height, port size, shape, effects, etc....

Another on intake.....then transfers, compression, pop-up pistons, etc.

Great idea!!

 

[kkemp]

What do you guys think about a series of threads dedicated to one aspect of the engine?

Like a thread on exhaust height, port size, shape, effects, etc....

Another on intake.....then transfers, compression, pop-up pistons, etc.

that'd be awesome.

 

[Mastermind]

http://opeforum.com/threads/part-one-the-exhaust-port.7279/#post-385036

 

[GoBigBlue1984]

You da man Randy!

 

[Mastermind]

Everything I know about this stuff I learned from guys on these forums. Maybe we can spur conversation that will help others learn.

 

[GoBigBlue1984]

David young got me into porting. Very intelligent, informative guy. A great guy. I still to this day ask him many questions. I haven't known Joey as long but he's another that has helped me tremendously. If there's something I don't know or fully understand, I shoot one of those guys a text. They've been incredibly gracious to share information with me and I'm grateful more than they'll ever know.

That being said I've picked up lots from any number of guys on the forum. Randy, Al, Deets, the list goes on and on and on.

I completely agree Randy, let's get some of this stuff out into the open so others (including myself) can pull from it.

 

[jacob j.]

Any chance of using 576XP stuffers on other cranks?

The 570/575/576 stuffers should be able to be made to fit the 475/2077/2083/505 cranks with a little work. The crank throws on all are about the same rough dimensions.

If it were me, I'd go with the crank stuffers and an RWJ-4 carb (in fact I'll be doing that very build this summer). The 475/505/2077/2083s can be a bit finicky because of the large openings of the lower transfers directly into the case. It's easy to make the engine lazy and lose throttle response.

 

[GoBigBlue1984]

The 570/575/576 stuffers should be able to be made to fit the 475/2077/2083/505 cranks with a little work. The crank throws on all are about the same rough dimensions.

If it were me, I'd go with the crank stuffers and an RWJ-4 carb (in fact I'll be doing that very build this summer). The 475/505/2077/2083s can be a bit finicky because of the large openings of the lower transfers directly into the case. It's easy to make the engine lazy and lose throttle response.

This one has been snappy JJ. I'll post that first vid after getting the saw back together.
David mentioned kitting the carb which I haven't done.

 

[jacob j.]

This one has been snappy JJ. I'll post that first vid after getting the saw back together.
David mentioned kitting the carb which I haven't done.

I'll throw an RWJ-4 in your box just in case you want to try one.

 

[GoBigBlue1984]

Thank you JJ

 

[Dub11]

Everything I know about this stuff I learned from guys on these forums. Maybe we can spur conversation that will help others learn.

Someone going to have to help me read first.

 

[Cut4fun]

The 570/575/576 stuffers should be able to be made to fit the 475/2077/2083/505 cranks with a little work. The crank throws on all are about the same rough dimensions.

If it were me, I'd go with the crank stuffers and an RWJ-4 carb (in fact I'll be doing that very build this summer). The 475/505/2077/2083s can be a bit finicky because of the large openings of the lower transfers directly into the case. It's easy to make the engine lazy and lose throttle response.

Just to show stock lowers of what your talking about.

LEFT 475 505

NOS

 

[GoBigBlue1984]

My little girl had a T-ball game tonight but I had a little time once home to play with the carb some and get a little more run time on this piston. Compression by the way is healthy. I'm guessing 170ish. Which is encouraging. I wasn't shooting for high compression numbers with this saw but 170 I'll take it.

 

[GoBigBlue1984]

Just to show stock lowers of what your talking about.

LEFT 475 505

NOS

View attachment 68336

Do you have measurements from the BB 372 piston you've ran before in these? Crown to pin and skirt length.Or how about any timing numbers?

 

[GoBigBlue1984]

Young had a good point in our conversation earlier. He suggested the BB 372 piston for the longer skirts which would get my intake duration down as well as boosting base compression. I'll prolly go ahead and order one and take a closer look. Although, I am liking where this one is headed.

 

[Deets066]

Young had a good point in our conversation earlier. He suggested the BB 372 piston for the longer skirts which would get my intake duration down as well as boosting base compression. I'll prolly go ahead and order one and take a closer look. Although, I am liking where this one is headed.

 

[Cut4fun]

Do you have measurements from the BB 372 piston you've ran before in these? Crown to pin and skirt length.Or how about any timing numbers?

I wouldnt use one for a hot ported saw. BB = aftermarket. But it was a drop in for stock.

Is that dominate 52mm or stock 50mm? That would be nice if 52mm

 

[Deets066]

Is that dominate 52mm or stock 50mm? That would be nice if 52mm

50 mm

But similar pistons can be had in 52mm
@mdavlee would know more about em