Husqvarna 262xp Bigbore

[Stihlsawshop]

Glad this thread is back. I was thinking about an 038 Super jug. 2mm bigger.

The issue here is case volume. Filling a jug that’s 4mm bigger is gonna be a tall order. The case volume to saw displacemt makes a huge difference.

I looked at my 038 magnum cylinder last night and I think I figured out how to put it together. If I use a manifold from a 37XP it ends up almost the perfect length to run the stock carburetor and air filter support. I didn't give the case volume issue much thought but I am now that you have brought it up and I see your point. I think I can get this together easier than I initially planned so I may give it a try soon. Getting the impulse feed is the issue that I see.

 

[drf255]

I’m referencing this point because of the common 044/046 hybrid swap. The top end is only 2mm larger, yet there is a significant difference in how the same top end will run on the 2 different cases.

OTOH, the 038 came in 48/50/52 variations on the same case. It’s possible that the 52mm swap may be just fine.

Which intake manifold are you suggesting?

 

[Stihlsawshop]

I’m referencing this point because of the common 044/046 hybrid swap. The top end is only 2mm larger, yet there is a significant difference in how the same top end will run on the 2 different cases.

OTOH, the 038 came in 48/50/52 variations on the same case. It’s possible that the 52mm swap may be just fine.

Which intake manifold are you suggesting?

I am gonna try the pre EPA intake manifold that fits the the 365/372XP saws. I have to modify the bolt pattern on the base of the cylinder and remove a fin on the lower left side of the cylinder with my mill. That is the only things I see that needs to be modified. The cylinder I hafe is a aftermarket 52mm size. I am gonna use a stihl muffler just to see if it works and develops power. If it does produce results I will lower the exhaust port on the Husqvarna muffler. I will then build the block-off wall around the intake that keeps trash out of the filter compartment.

 

[drf255]

I bought a 50mm oem 038 P&C as well as a 52mm AM version.

HL supply had the 52mm kit on sale for $29.99 yesterday.

For initial fit, I’d rather hack up the AM jug first.

Any pics of that 372 manifold?

 

[Stihlsawshop]

I bought a 50mm oem 038 P&C as well as a 52mm AM version.

HL supply had the 52mm kit on sale for $29.99 yesterday.

For initial fit, I’d rather hack up the AM jug first.

Any pics of that 372 manifold?

Any thoughts on the problem with the impulse feed? The only one I have is to drill a hole in the base of the cylinder like a 395 and install a hosebarb.

 

[Stihlsawshop]

Any thoughts on the problem with the impulse feed? The only one I have is to drill a hole in the base of the cylinder like a 395 and install a hosebarb.

Of course that will snowball into sourcing another carburetor because of the impulse feed. Alot of aggrevation to get this to fit. I wish the guy with the original 038/261 hybrid would respond on power output. It would probably save me some time.

 

[drf255]

The Stihl 044 HD series carb was fit by @wcorey. Bills a talented guy, but he didn’t say it was too difficult.

I can only think of a barb from the case or as you said, jug base.

I’d have to have it mocked up to see where.

 

[drf255]

@RanchDad

 

[Stihlsawshop]

@RanchDad

I am gonna place a hosebarb in the cylinder base as opposed to drilling into my crankcase. I dont care to modify that at all. Anyhow, it will be a few days before I go any further with the project.

 

[drf255]

I’m up to my ears in 044/6 hybrids right now. Won’t be touching this for some time.

 

[Stihlsawshop]

I’m up to my ears in 044/6 hybrids right now. Won’t be touching this for some time.

I know what you mean. This little project is for me and that doesn't pay anything either. I guess the first thing I should install the piston and make sure it will clear the crankcase. I haven't even verified that yet. On the 044/046 hybrid, is there anything to be gained other than a weight savings? I frequently use the 044 aftermarket tank/handle assemblies to put crushed 046 and MS460's back together. Just change to the longer carburetor studs and they work.

 

[drf255]

A lot more power in a smaller package. An 046 case will make more torque and has a stronger crank.

I use a cut down 272 piston to allow the 52mm to weigh the same as an 044 piston and not the heavier 046 piston on the smaller crank.

 

[drf255]

The 272 slug allows a single thick ring with a centered pin.

 

[drf255]

 

[Stihlsawshop]

A lot more power in a smaller package. An 046 case will make more torque and has a stronger crank.

I use a cut down 272 piston to allow the 52mm to weigh the same as an 044 piston and not the heavier 046 piston on the smaller crank.

I see. Until just recently I have only been doing straight overhauls. I have started to do port work and lowering squish bands on my own saws. I have a nice lathe and milling machine and recently got out of machinist school. I am having trouble getting a grasp of timing on the saws. I have a degree wheel and all the tools I need I am just failing to see if its worth it to me to spend so much time on a saw. It takes a considerable amount of time to tool up and cut the squish, port and polish intake and exhaust, modify the muffler, and then get the timing right. I don't see how I can pass that much extra labor along to a customer and not eat a portion of my time. This is my only income and has been for the last year and I enjoy it enough I dont want to burn myself out.

 

[drf255]

Unlabeled piston is 046 meteor. HW is Hyway 272. Plain 272 meteor is stock. The numbers slug has that much off the crown.

FWIW, oem 046 piston weighs 79 grams. An 044 piston is around 72 grams.

 

[drf255]

I see. Until just recently I have only been doing straight overhauls. I have started to do port work and lowering squish bands on my own saws. I have a nice lathe and milling machine and recently got out of machinist school. I am having trouble getting a grasp of timing on the saws. I have a degree wheel and all the tools I need I am just failing to see if its worth it to me to spend so much time on a saw. It takes a considerable amount of time to tool up and cut the squish, port and polish intake and exhaust, modify the muffler, and then get the timing right. I don't see how I can pass that much extra labor along to a customer and not eat a portion of my time. This is my only income and has been for the last year and I enjoy it enough I dont want to burn myself out.

Very hard to make money on saws. I’m not a pro, I’m a hobbyist.

The big guns here generally charge around $300 for the machine work, grinding, timing advance and muff mods. All parts and extra work is extra.

A hybrid runs around $450 in labor plus parts.

Some guys are willing to pay for it. You’d be suprised.

 

[drf255]

BTW, base and band cuts are both done on a lathe. A band takes around 30min to setup and cut.

Make a plate with studs and nuts and the use a coaxial indicator. I’ll see if I have a pic.

You just need a mandrel for base cuts. Don’t be shocked by how far off the OEM can be.

 

[drf255]

 

[Stihlsawshop]

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I made a mandrel to do my base cuts and use a live center to hold it on there. I have made a couple of different sized mandrels so far and made them from aluminium. I was told the other day to build them from wood and would not have thought of that. I have taught myself how to re-key a flywheel but the problem I am having is I have only changed 3 or 4 degrees and I can't cut a new keyway because it will overlap the old one. So I am just putting the flywheel where I need it and snug down the nut and let the taper hold it. I would never do one like that for someone else. I have no concept of figuring blow down and other internal port factors yet either.