Dolmar 6400/8400

[LD1]

I bought the BBN7900 kit from baileys and installed it friday and yesterday.

It is not completely broke in but it is indeed impressive.

Cutting in 10-12" ash, it picked up about 2-3seconds over dads still stock 6400. I also opened up the muffler a bit.

I was a bit disappointed though as even without the gasket I could only get the squish down to .038. But If I tried to go any more by milling some off the base, The exhaust would free-port. The tech a baileys said this is about normal and to give it a try anyway. We'll see how she does once fully broke in.

Here is a pic just to show the difference in bore size.

 

[RandyT]

The ps6400 and ps7300 piston and cylinder supercede to the ps7900 even if you order the parts from a dolmar dealer. in other words in you go to your local dolmar dealer with a ps6400 and order a piston/cylinder you will the ps7900 piston/cylinder assy.

 

[LD1]

The ps6400 and ps7300 piston and cylinder supercede to the ps7900 even if you order the parts from a dolmar dealer. in other words in you go to your local dolmar dealer with a ps6400 and order a piston/cylinder you will the ps7900 piston/cylinder assy.

Yep, that is correct. But that is also true on almost all saws that share the same chassie. Like the 365 and 372 husky, and the 029 and 039 stihls just to name a few. But New OEM is north of $300. With the aftermarket ones at $99, I figured it was worth the risk. And the NWP's seem to get fairly decient reviews on AS. Everything looked good. The NISI coating and the moly on the piston looked really good. The only disappointment was the higher squish number than I wanted.

 

[Storm56]

I have 2 6401's, and a BB kit in my garage waiting....

I have yet to hear of someone that put this kit on that did not like it. Positively cannot beat the price. So far I have been quite pleased with the performance of the stock 6401 with the 20 inch bar. But I know that one of these days when I get bored, that kit will find it's way on a saw....

 

[frischtr]

I just installed the NWP BB kit as well. With no base gasket I was at .018, which is a little too tight for my taste. I am running the stock gasket from the 6401 which gets me to about .038. I could go tighter with a custom gasket but I'll break it in as it stands now. My compression after 1 tank is 165 psi. The NWP isn't of the quality of OEM, but hard to beat at 1/2 the cost...

 

[LD1]

I just installed the NWP BB kit as well. With no base gasket I was at .018, which is a little too tight for my taste. I am running the stock gasket from the 6401 which gets me to about .038. I could go tighter with a custom gasket but I'll break it in as it stands now. My compression after 1 tank is 165 psi. The NWP isn't of the quality of OEM, but hard to beat at 1/2 the cost...

I wish I could have gotten that low.

But even If I milled it, I'd be free-porting the exhaust

But it still seems to have good compression and power even @ my current ~.040 and NO gasket. But I havent actually done a comp test yet as I have only got 1/2 tank through it