375xp-51.4mm

[parrisw]

Been a while since I've really been around, been a longer while since I've posted a build, so I thought I'd share my latest.

Going to have to bear with me as usual, I'm slow, and have many other things going on in my life besides chainsaws these days. First time doing a xpw cylinder, so any of you guys that have done them before please chime in. Transfers are sure stuffed up compared to a 50mm cylinder.

As you can see I got lots of parts to go through. As usual, I build from a box of parts.

 

[tdi-rick]

Subscribed

 

[parrisw]

Measured squish, sitting at .030 with gasket, tighter then a 50mm cylinder, they are usually about .043" on most ones I've done.

 

[leeha]

Sweet project, Subscribed




Lee

 

[parrisw]

Sweet project, Subscribed




Lee

Thanks, been anxious to do this build for a while now.

 

[duramax99]

Sounds like the perfect saw for a 390 carb swap ;-)

 

[parrisw]

Sounds like the perfect saw for a 390 carb swap ;-)

Yes was thinking that. I haven't forgotten about you.

 

[wyk]

Sounds like the perfect saw for a 390 carb swap ;-)

I've seen some very strong 372's with just some mild stock carb boring.

 

[duramax99]

No worries will ive been too busy trying to buy a house to even think about saws.

 

[parrisw]

No worries will ive been too busy trying to buy a house to even think about saws.

Congrats on buying a house! You'll like it when all is said and done.

 

[SawTroll]

Sounds like the perfect saw for a 390 carb swap ;-)

Not sure that helps much, as the venturi is basically the same?

 

[mdavlee]

The 390 carb is around 19 mm if I remember right. It's about the same as the xt carb. I can't remember what the 372 carb is right now.

 

[moody]

The 390 carb is around 19 mm if I remember right. It's about the same as the xt carb. I can't remember what the 372 carb is right now.

I believe stock is 18 there are great gains to be had from this swap.

 

[SawTroll]

The 390 carb is around 19 mm if I remember right. .....

:msp_confused:The WJ 116 is 17.46, as is the HD 12 of the 372. The Tilly used on the early 390s are 17.5.

At least that is what the manuals tell me....

 

[moody]

:msp_confused:The WJ 116 is 17.46, as is the HD 12 of the 372. The Tilly used on the early 390s are 17.5.

Air flow play a big role in the performance gains. From what I've seen just the swap alone gets about about 700rpms more. Those Tilly's can be modified be couple guys on here to really grab so some gains.

 

[parrisw]

Not sure that helps much, as the venturi is basically the same?

I've heard the swap really helps, so I will try.

Not sure on the bore sizes.

 

[Boleclimber]

Air flow play a big role in the performance gains. From what I've seen just the swap alone gets about about 700rpms more. Those Tilly's can be modified be couple guys on here to really grab so some gains.

Drill out the fuel passages and run Alcohol through it. Noticeable gains will be seen.

 

[SawTroll]

Air flow play a big role in the performance gains. From what I've seen just the swap alone gets about about 700rpms more. Those Tilly's can be modified be couple guys on here to really grab so some gains.

Most if not all carbs van be modified to a larger venturi, but it will vary how much they can be opened.

Of course the could also be other factors that affect air and fuel flow - I am no expert!

 

[mdavlee]

The venturi on the 390 is a little over 17mm from some other posts I found. Maybe it was a 395 or 3120 carb I was thinking of at 19mm.

 

[parrisw]

The venturi on the 390 is a little over 17mm from some other posts I found. Maybe it was a 395 or 3120 carb I was thinking of at 19mm.

Hmm, I thought the 372 carb was that? So what's the advantage of a 390 carb? Bigger jetting?