Makita 6401 Big Bore Piston 84cc

[Paul Turner]

I recently Ebay purchased ($380) a Makita 6401 with a Big Bore (84cc) P&C already installed. After cleaning the carb and setting H 1 1/4 - L 1 1/16 I was able to start and run it. The starter pulls VERY hard w/o decomp, but feels fine using decomp.

The saw took over 3 weeks to be delivered and just before I received it the seller said this in email:
"when I run ,my saws, I used amsoil 100:1 oil. and I believe that is whats in the tank and still in the carb. If I was you I would make sure I poured that gas out and ran the engine till all that gas/oil was out of the carb. I would start using a 50:1 ratio of the new stihl synthetic."

This made me nervous and I pulled the muffler and have attached photos.:camera: Any input is appreciated.

I replaced the clutch drum, rim sprocket (3/8" 8 tooth), bar (20" Oregon Powermatch) and chain (Oregon 72 LGX). I was able to cut some 18" Elm today and the saw had no problem making short work of it.

The saw does have an oil leak which I'll tolerate for awhile. I'm just hoping the P&C hold up.

 

[wigglesworth]

Its hard to tell if that is the start of aluminum smearing or if it's just what's left of the moly coating. If it were me, I would pop off the jug and take a closer look at the skirt and check the cylinder out below the exhaust port for transfer, unless you plan on sending it back.

 

[AUSSIE1]

I can tell you one thing, he's over done the silastic.

 

[tdi-rick]

Its hard to tell if that is the start of aluminum smearing or if it's just what's left of the moly coating.
[snip]

It just looks like what's left of the moly to me, if you enlarge the pic it just looks like the marks from where the piston was turned to size.

 

[Cantdog]

It just looks like what's left of the moly to me, if you enlarge the pic it just looks like the marks from where the piston was turned to size.

+1 :agree2: The wierd discoloration looks to be whats left of the moly coating. And the machine marks are still very visable showing little if any sign of piston wear and shows no sign of scoring what so ever. Nice and clean as well, no carbon buildup even on the port. I'd run it------!!

 

[blsnelling]

There's nothing wrong with that piston at all. That is definately just remnants of the coating on the piston. It wears off within the first tank or two. I'm not sure why they even put it on there.

 

[WoodChuck'r]

Interesting. That's something I never knew. Learnin' something new everyday on this site.

 

[TRI955]

I was sweating there for a minute, I thought that was my old 6401 that I just sold....I'd never run Amsoil though. Piston looks good to me too.


Mike

 

[Paul Turner]

I feel better now...

Thank you for all the replies. This is a great forum and I really appreciate the information. I cut twenty to twenty-five cords of firewood every year and it seems this saw will make it more enjoyable. Most of the trees are less than 20" diameter, but I do have some over 40".
For the past 4 years I've been using Amsoil Dominator fully synthetic mixed @ 43 to 1 (6oz./2gal) and have had good results.

Again, thanks for the quick replies.

 

[jd548esco72]

looks like the piston coating to me.

the WEIRD part is looking at a un-ported BB jug!:greenchainsaw: