Mastermind Meets The MS660

[Mastermind]

I gave away a woods port in the Christmas thread on AS. This is that saw.

 

[Mastermind]

Tiny little exhaust outlet. We'll fix that.

 

[Canadian farm boy]

 

[Onan18]

 

[Mastermind]

Now I gotta get down the the bare crank stub to install my degree wheel. I wanted to check the timing numbers in this jug.......I'll show you why in a minute.

 

[Mastermind]

I have two different wheels I use. One is mounted on a 3/8", and the other is a 1/2" drill chuck. Just what I had handy.



Mike......AKA Homelite410 made me these aluminum discs. They are 7" in diameter. I just print off these degree wheels and glue em on.

 

[Mastermind]

As I take the saw apart there are a few things I do as I go.

First I go ahead and pull the carb limiters.



I've got the Stihl puller, but I made this one years ago, and I sorta like it.



This part is self explanatory I think.

 

[Mastermind]

Next is the ignition timing advance.



I don't use piston stops. I'm old school I reckon......so a rope goes in the jug.



Here's what I'm after......gotta thin that key.

 

[Mastermind]

The key measures about .078"



I lock it in a pair of Vice Grips, then stick them in the vice.



And file just the edge of it down.......



Now it's .058"......so I've taken off .020.

 

[Mastermind]

Now, this part is tricky to explain. To make sure you get your advance, use a rope in the jug as a piston stop, then hold the flywheel tightly counter-clockwise against that stop. While holding it, snug the flywheel nut up.

 

[Mastermind]

Now.......remember what I said about wanting to check these timing numbers?

It looks like this is a MS660 decomp jug.......made by Kolbenschmidt. I was sort of excited......

 

[Adirondackstihl]

The key measures about .078"



I lock it in a pair of Vice Grips, then stick them in the vice.



And file just the edge of it down.......



Now it's .058"......so I've taken off .020.

Always wondered how you went about doing that!

 

[Mastermind]

Turns out........it was not.

This is not an MS660 I have on my bench at all. It's an MS650. lol

 

[Mastermind]

Not a 54mm bore.........it's a 52mm bore. But, that's ok with me. I can make these saws really come alive. They don't quite make the torque that a 660 makes. But they wind up sporty as hell.

 

[junkman]

Nebber seen a Ks jug on a 660 yet

 

[Mastermind]

Here's a little trick I use. On these saws without cylinder extensions, I use a couple of dowels made from all thread rod. That keeps the gasket in place, and allows me to easily center the jug when checking port timing.

 

[Andydodgegeek]

I don't claim to know at all what I'm doing. Good to see someone that does. Nice write up so far Randy.

 

[junkman]

So a modern day 064 ?

 

[Mastermind]

All set up for timing measurements.



The port timing on this jug stock.....

Ex: 94*
Tr: 124*
In: 81*

 

[Mastermind]

So a modern day 064 ?

Exactly. But with way higher timing numbers.