372 xpw cylinder?

[Mastermind]

I ground all those aluminum chips out of an XPW jug a couple of days ago.....

 

[Jacob J.]

What's the advantage of the 12.

The 12 has a bigger (wider) venturi opening and a larger fixed main jet than the 6.

 

[Mastermind]

The XT carb is even bigger....

 

[Chainsaw Jim]

Ok guys here is what I have done. I ground out the hump best I could. Used the gasket to make sure it matches the case which it did pretty well. I also lowered the skirt at the transfer inlet. Pretty much even with the base. I didn't want to get to aggressive as this is my first time doing something like this. I also put the heat shield on and ground out the exhaust to match the shield. Sorry I forgot to take a picture. I am going to use an hd6 carb as it is all I have. And I haven't modded the muff and I know I need to but I'm not sure how. I'm not good at brazing. And I don't have any deflectors.

Feel free to criticize and tell me I'm doing it all wrong. I'm here to learn.

It looks pretty good. Here's a pic of a more extreme port job on an xpw so you'll be able to feel more confident about the work you've done. I had to modify the piston to match for maximum flow.






There is a simple experiment for those who don't understand how bridge porting works....
Take a couple inch piece of the larger fuel line and breathe through it and see how long it takes you to fight for breath from lack of air. Cut a 1/4 inch chunk from it and breathe through that and you'll have no problem getting air.
The diameter of the hole stays the same but the volume doubles.

 

[Whitty21]

I read through the thread out of interest and couldn't didn't anything saying that the xpw isnt a direct bolt on to a regular 372. Just grind the hump on the intake? Same carb and such? If this is too much of a question tell me to shut up and quit threadjacking.

 

[Chainsaw Jim]

I read through the thread out of interest and couldn't didn't anything saying that the xpw isnt a direct bolt on to a regular 372. Just grind the hump on the intake? Same carb and such? If this is too much of a question tell me to shut up and quit threadjacking.

Direct bolt on is correct. I think HD12b is the carb the xpw comes from the factory with.

 

[idiotwithasaw]

I think the hd12b is what all 372 up to the xtorq came with, the 371 came with the hd6. From what I understand. This is an oversimplified explanation and I'm sure someone will know more.

 

[idiotwithasaw]

The XT carb is even bigger....

how do you mount it. I want to go that route, but it came to my attention that the 390 boot was a tad too big, I checked and it is. What's the best way of getting it to work?

 

[idiotwithasaw]

I ground all those aluminum chips out of an XPW jug a couple of days ago.....

View attachment 472755

I would love to see some more close up shots of this cylinder. Maybe even a few timing numbers????

 

[Mastermind]

You use a 372 boot, but twist it on the spigot CCW a bit. You need to cut the piece some that the impulse goes thru so it doesn't hit the top cover. Then you need a XT air filter base.

 

[Mastermind]

They work huh?

 

[Mastermind]

Good ider. As many saws as I do, I try my very best to work with all the stock parts. When I build "special" saws, more folks ask about them.......that tends to slow down the process.....

 

[idiotwithasaw]

Has anyone posted any pics or made any threads of how to trim the boot. I'm really interested in doing this.

 

[Mastermind]

Just get everything together, it's self explanatory....

 

[beaglebriar]

I plan to try the x torq carb on my 385. I assume it's straight forward. If not I'll figure it out. That's half the fun!

 

[idiotwithasaw]

With a 385. I assume it's a direct replacement. On the 372 do you just remove the whole peice that the impulse line goes in. If so do you put something I'm it to keep the air box sealed?

 

[Mastermind]

Just trim it......No reason to take it completely off.

 

[idiotwithasaw]

But won't there be a gap?

 

[idiotwithasaw]

I wonder if you could use the plastic part off of a 390 boot and trim the boot for the carb bolts.

 

[idiotwithasaw]

Ok guys here are some pics of what I did to get the xtorq carb in. I did as @Mastermind suggested and turned the original boot till it lined up. I had to fiddle a little to get it lined up right. Then I trimmed the rubber piece that t he impulse goes through. I had to trim some of the plastic back on the throttle cable as it wasn't letting it go all the way back to idle, too tight. I used the xtorq filter horn and a oem 372 filter. Also had to use the xtorq choke which wasn't unexpected.

I started her up and set my idle, haven't had a chance to put her in some wood to fine tune the high as I literally did this 20 minutes ago after Christmas dinner. Lol
It four strokes good and sounds strong. Now I just need a good muffler mod and I'll be good to go.