372XT to XPW Conversion Question.

[Steve]

I have a new husky xpw 51.4mm p&c coming along with a top cover, intake boot, choke lever, air filter adapter, carb adjustments boot, screws, and carb.

What is the best stock carb to run on this setup? I have an HD-12A coming so I can get up and going. I seen there is also a HD-12B and a Zama option.

This is my first Husky build so I'm not extremely edcuated in the 372 line yet!

Thanks.

 

[dustinwilt68]

Stock either hd12 is great, some really like the xtorq carb also, it has a very large venturi, but it mounts a little sideways if i remember correctly, but it still funtions properly

 

[Steve]

Stock either hd12 is great, some really like the xtorq carb also, it has a very large venturi, but it mounts a little sideways if i remember correctly, but it still funtions properly

Thanks. I figured the hd12 was the better choice because everyone had it priced higher than the Zama! I heard of people running the xt carb but it is more finicky than the "correct" carb.

 

[huskyboy]

Thanks. I figured the hd12 was the better choice because everyone had it priced higher than the Zama! I heard of people running the xt carb but it is more finicky than the "correct" carb.

Stick with the hd12, it runs out fine and has a larger venturi than the zama. You will have to turn the boot sideways and trim it to get it to run a 395xp carb (similar to rwj swap). The throttle cable and throttle cable holder on the carb will need modified too. Not sure it’s worth the effort for a stock saw.

 

[Steve]

Yep, just keeping it stock and reliable.

 

[blsnelling]

I prefer the XT carb, filter adapter, and filter. The XT carb has the largest venturi and throttle plate of any carb that I'm aware of for these. I have had no issues at all running them. I would use a 390 intake boot. You could have saved quite a bit of money too.

 

[Derf]

Don’t listen to Brad, just keep it simple.

The Walbro HD12B was the stock carb, on the Husky 365, 372xp, and even 372xpw. Hell, even Dolmar used the smaller Venturi Zama carb on their 7900. So don’t worry that the Walbro doesn’t flow enough for the saw.

People like the Zama because it has separate hi/low and idle circuits, which allows for modding the carb. Poleman modifies the carb for people, but they are usually for ported saws that can benefit from the modded carb. They are actually pretty hard to source the correct C3M Zama carb though.

People have used a RWJ-4 X-torq carb off the 372xp XT, or even a 390XP carb, thinking the bigger Venturi flowing more is better. While the vennturi IS bigger, it has a divider, as it is set up to run into the early strato cylinder. Half the carb isn’t flowing fuel mix, but just straight air. It isn’t jetted to flow like a big bore carb.
The other downside is the mounting holes are at 10 and 4, instead of 9 and 3, so the carb would sit cocked. You have to change a bunch of other parts to make it sit right.

Other people have used a Tilly carb. My thoughts on that are similar to the RWJ-4.

The 51.4mm XPW cylinder will benefit from some porting to take advantage of the available power. After you drop the $$ on that, you can chase carb options.

 

[Steve]

I prefer the XT carb, filter adapter, and filter. The XT carb has the largest venturi and throttle plate of any carb that I'm aware of for these. I have had no issues at all running them. I would use a 390 intake boot. You could have saved quite a bit of money too.

It only cost me 50 bucks for all the xpw induction used. I'm not getting it ported so I don't think I'd gain much from the biggest bolt ons. If it ever gets there then I'll go that route.

 

[wcorey]

Why the xpw, is the xt cylinder toast?
Due to the stuffed up transfers, I'm not sure the xpw has any performance advantage over oe or xt top ends (without porting).

 

[blsnelling]

Don’t listen to Brad, just keep it simple.

The Walbro HD12B was the stock carb, on the Husky 365, 372xp, and even 372xpw. Hell, even Dolmar used the smaller Venturi Zama carb on their 7900. So don’t worry that the Walbro doesn’t flow enough for the saw.

People like the Zama because it has separate hi/low and idle circuits, which allows for modding the carb. Poleman modifies the carb for people, but they are usually for ported saws that can benefit from the modded carb. They are actually pretty hard to source the correct C3M Zama carb though.

People have used a RWJ-4 X-torq carb off the 372xp XT, or even a 390XP carb, thinking the bigger Venturi flowing more is better. While the vennturi IS bigger, it has a divider, as it is set up to run into the early strato cylinder. Half the carb isn’t flowing fuel mix, but just straight air. It isn’t jetted to flow like a big bore carb.
The other downside is the mounting holes are at 10 and 4, instead of 9 and 3, so the carb would sit cocked. You have to change a bunch of other parts to make it sit right.

Other people have used a Tilly carb. My thoughts on that are similar to the RWJ-4.

The 51.4mm XPW cylinder will benefit from some porting to take advantage of the available power. After you drop the $$ on that, you can chase carb options.

Lol.

No one said the HD12 didn't flow "enough".

"A bunch more parts"?
You mean an intake boot? That's it. He's having to replace that anyway.

The divider in the carb is of no concern. It works great with or without it. I've used them both ways.

Let's keep this simple The simplest way would have been to re-use almost all of the XTorq parts, which is what I'm suggesting.

 

[Steve]

Why the xpw, is the xt cylinder toast?
Due to the stuffed up transfers, I'm not sure the xpw has any performance advantage over oe or xt top ends (without porting).

I want an xpw and huskys cylinder kits are too affordable to not convert it. Cheaper than selling this one and buying an unknown condition of a true xpw. Most second hand xpw saws are beat to crap.

All in all just going to do it cause I want to. That's all.

 

[huskyboy]

I want an xpw and huskys cylinder kits are too affordable to not convert it. Cheaper than selling this one and buying an unknown condition of a true xpw. Most second hand xpw saws are beat to crap.

All in all just going to do it cause I want to. That's all.

The xpw has more torque than the other cylinders stock and ported imho.

 

[Steve]

Lol.

No one said the HD12 didn't flow "enough".

"A bunch more parts"?
You mean an intake boot? That's it. He's having to replace that anyway.

The divider in the carb is of no concern. It works great with or without it. I've used them both ways.

Let's keep this simple The simplest way would have been to re-use almost all of the XTorq parts, which is what I'm suggesting.

I just wanted it to be an "xpw" all the way through. The intake boot was 22 bucks at my dealer and I found all the parts used cheap so I figured why not go that route.

 

[Derf]

The OE/XPW have a different top handle from the X-torq too. It’s lower down on the OE, and taller on the x-torq (because the cylinder and top cover are taller)... if you’re going all the way.

 

[Steve]

The OE/XPW have a different top handle from the X-torq too. It’s lower down on the OE, and taller on the x-torq (because the cylinder and top cover are taller)... if you’re going all the way.

Got both the proper top cover and full wrap and spikes too. Even the starter cover decal!

 

[Chainsaw Jim]

Lol.

No one said the HD12 didn't flow "enough".

"A bunch more parts"?
You mean an intake boot? That's it. He's having to replace that anyway.

The divider in the carb is of no concern. It works great with or without it. I've used them both ways.

Let's keep this simple The simplest way would have been to re-use almost all of the XTorq parts, which is what I'm suggesting.

The 51.4mm jug has about 1/3 less transfer flow than the 50mm 372, so the idea is to use a larger carb?

 

[XP_Slinger]

For the OP...I swapped an XPW topend onto my XT last year. I opted to run my XT carb and have had zero issues with it. The only thing out of the ordinary you have to do is clock the intake so the carb mounts straight. It’s really not as labor intensive as some make it sound. Nothing wrong with your plan to run the stock carb, my saw is ported so I figured I’d try the XT carb.

Brad (blsnelling) is a great builder and knows 372’s, I take notes when he’s talking...lol

 

[Steve]

For the OP...I swapped an XPW topend onto my XT last year. I opted to run my XT carb and have had zero issues with it. The only thing out of the ordinary you have to do is clock the intake so the carb mounts straight. It’s really not as labor intensive as some make it sound. Nothing wrong with your plan to run the stock carb, my saw is ported so I figured I’d try the XT carb.

Brad (blsnelling) is a great builder and knows 372’s, I take notes when he’s talking...lol

I agree. Just figured as cheap as I found the "correct" parts I'd just go that route. If I ever get it ported down the road...

 

[XP_Slinger]

I agree. Just figured as cheap as I found the "correct" parts I'd just go that route. If I ever get it ported down the road...

Nothing wrong with that at all my friend.

 

[huskyboy]

It’s funny the most “despised” (at least on here) cylinders on the 372’s are the ones I like the most (xtorq and xpw). You can just give them that extra “push”... good torque. The 48/50mm feel more lively and rpm based to me. The next 372 I get however, I wanna try a 50mm with the weisco piston.