390XP sprocket size

[CallumA]

A question for the saw Gurus what size sprocket is a 390 xp supplied with as standard 7 or 8 tooth. The reason I ask is Ive fitted a jungle muffler and a carb off of a 372xt and the saw is a bit of an animal now. I wondered if it is worth upping the sprocket size for cross cutting fire wood with a 24" bar?? I would normally go to the shed and check but at work at the moment and would like to order parts before I come home:confused1:

[adw]

Carb off a 372XP onto a 390????????why???? the saw would have been supplied as standard with a 7 tooth rim

[Stubby]

A question for the saw Gurus what size sprocket is a 390 xp supplied with as standard 7 or 8 tooth. The reason I ask is Ive fitted a jungle muffler and a carb off of a 372xt and the saw is a bit of an animal now. I wondered if it is worth upping the sprocket size for cross cutting fire wood with a 24" bar?? I would normally go to the shed and check but at work at the moment and would like to order parts before I come home:confused1:

 

Come standard with a 7 . Just for your info I have a 390 ported by spud . It is on a 28" 3/8 and I find it better on the standard 7 for more torque . I would suggest you try an 8 and see how it goes . If it bogs wjhen you lean on it go back to a 7 . Let me know ...

[Stubby]

Carb off a 372XP onto a 390????????why???? the saw would have been supplied as standard with a 7 tooth rim

 

Its a recognised mod . The 17mm veturi on the standard carb is a little conservative . The 19mm is a bit better many people think .

[Joe Newton]

I find that gearing up sprockets only really works on mid range saws with little bars. I run 8pin sprockets on my 357 on 15" and 550xpg on 13". I have a 441 with muffler mod that I run on 20", but I've stuck to 7pin on that as on larger saws torque is more important than chain speed, IMO.

[adw]

372 carb on a 390 works? i certainly learnt somthing.

[Stubby]

372 carb on a 390 works? i certainly learnt somthing.

 

Its the 372Xtorque rather than the earlier 372Xp that people are using .

[CallumA]

Come standard with a 7 . Just for your info I have a 390 ported by spud . It is on a 28" 3/8 and I find it better on the standard 7 for more torque . I would suggest you try an 8 and see how it goes . If it bogs wjhen you lean on it go back to a 7 . Let me know ...

 

 

I'll get a sprocket and try it! trial and error and see what works best. Thanks guys:biggrin:

[Reddog]

7pin is stock as others have said.

I am currently run a 8pin on my 390xpg with a 20" and 25" bar. As Stubby said try one and see. I like the extra chain speed.

But if your hamfisted it might stall in the cut to easy.

 

 

Hadn't heard of the xt carb swap.

I have a 372xt I converted back to a xp. May need to swap the carbs with the 390xp.

Edited February 7, 2015 by Reddog
I am a slow typer

[SawTroll]

Its the 372Xtorque rather than the earlier 372Xp that people are using .

 

Yes, the 19+mm RWJ-4 372xt carb can help quite a few saw models - but isn't always a streight bolt-on. Of course the devider in there should be removed.