MS660 Rebuild help.

[armytaco]

First off I have searched ALOT on the matter. I cannot seem to find all the answers I need. Here is my plan;

BB kit from Baileys. Have not looked at the stock jug but gonna set it aside if it is reusable for a later project.
What gaskets do I need and where to get them from? I have been looking and looks like just one for the cylinder. Will Baileys have this if I ask them?
After I assemble everything how do I check the squish? I know about the solder test but exactly how do you do it? Or do I just assemble and let it ride? Assemble everything with a piece of solder and roll it over then measure? Walk me through everything I need to get this beast where it needs to be.

I am waiting to order so I can get everything in one go. Thanks for your help.

 

[mtngun]

I can't remember if a base gasket is included in the current BB kits. You might want to ask Grande Dog.

If not, your old gasket will prolly work BUT check to make sure the piston skirt doesn't rub the gasket at BDC. This was a problem with some of the older BB kits, they corrected it by shortening the skirt a hair and I THINK including a special gasket with the kit.

Your squish should be fine as long as you use a base gasket, but it's always a good idea to check. You can insert solder through the spark plug hole, let the piston come up above all the ports, then insert the solder until it is pressing against the cylinder wall. Now bring the piston up to and past TDC to squash the solder.

More correctly, you can use two pieces of solder simultaneously, one on each side of the cylinder, to rule out the piston rocking and throwing off the measurements.

Or assemble the saw minus rings, "glue" pieces of solder to the edge of the piston with grease, then pop the cylinder off to retrieve and measure the solder.

If you don't already have them, the ring compressor kit that Bailey's sells is handy and cheap.

Make sure that whatever problems the saw had in its prior life have been identified and fixed, otherwise they will come back to bite you.

 

[pinemartin]

Rule #1

FIND OUT WHAT CAUSED THE PISTON FAILURE BEFORE JUST DROPPING ON ANOTHER JUG AND SLUG...

Reasons for a sesure could be something like strait gas, bad impulse hose, or leaking crank seals to name a few. If you do not find out the reason of the failure and fix it than your replacement parts may become the parts you need to replace.

 

[armytaco]

No seizure just an 8 year old saw that has been used alot and has low compression. It still runs and everything just is a little low on power. Has 125psi compression. Thats why the rebuild and just gonna do the BB kit because I would like to keep the stock jug especially if it is in good shape. Thinking about a woods port later down the line a little and would rather just use the NWP BB kit and get it ported and have a backup jug if need be later. No failures or anything.

 

[tlandrum]

it comes with the base gasket. personally if the oem is good id rering it. i have a bb but prefer the oem

 

[angelo c]

I'ld replace the impluse and intake hose as well since I'm that far in and already apart. I'ld check the squish just to make sure nothing is hitting either way, by means of rocking or topping out in the jug.

 

[armytaco]

Whats the impulse? I am pulling the cylinder off as we speak.

 

[blsnelling]

The last generation 066 BB kits are very nice. I'm quite confident it comes with a gasket. You will need it more than likely. My 066 only has about .017 with a factory gasket and a OEM topend. Inspect your rubber parts. No reason to replace them if they're not deteriorating and/or cracked.

 

[blsnelling]

Whats the impulse? I am pulling the cylinder off as we speak.

A rubber hose from the case, just below the rear of the cylinder, to the carb box.

 

[angelo c]

No reason to replace them if they're not deteriorating and/or cracked.

Respectfully disagree Brad,

The saw owner is telling us the saw is "worn" and indicates low compression due to use. I would think he should at least pressure test all the rubber but adding $10 of an impulse hose at this time seems to be a worthy investment.

I don't see this as a worthy opportunity to pinch a few pennies...but it's his saw and he seems to be in the early stages of the learning curve.

 

[blsnelling]

It's easy enough to stretch and inspect impule lines, fuel hoses, and intake elbows to inspect for cracks and detereoration. Stihl get's too much for their parts to begin with.

 

[armytaco]

Well looks like I might need a crank bearing. There is some side to side movement. No up and down. Does this need to be replced? Is the side to side ok since the piston centers in the cylinder.


How do I get down to the crank if need to?

Old piston has some wear marks on it as well as the cylinder. Nothing huge but I can catch my fingernail on them.

 

[angelo c]

It's easy enough to stretch and inspect impule lines, fuel hoses, and intake elbows to inspect for cracks and detereoration. Stihl get's too much for their parts to begin with.

Don't disagree with that statement but as with most things mechanical, I've found that the parts are the cheaper half of the solution, it's the replacement time that is the most expensive half. Better to replace rubbers when its apart and know their age to me. Surely a builder would understand this point of view. Not arguing at all Brad just stating an overly cautious position . Hoping to avoid some future fustrations for a newer guy.

 

[angelo c]

Well looks like I might need a crank bearing. There is some side to side movement. No up and down. Does this need to be replced? Is the side to side ok since the piston centers in the cylinder.


How do I get down to the crank if need to?

Old piston has some wear marks on it as well as the cylinder. Nothing huge but I can catch my fingernail on them.

It's "post a few photo's" time....now you are asking for some innernet oppinions and we all know how many of us has a few of them....

 

[armytaco]

Well I am not as worried about the top end as the bottem end right now. So what about the crank area? I am guessing they need replacing. All the research I have doen seems that the bearings should be tight with no play and I do believe mine has some play.

 

[Saw Dr.]

Side to side on the rod is no problem. Up and down is a deal breaker. Probably fine.

 

[angelo c]

Well I am not as worried about the top end as the bottem end right now. So what about the crank area? I am guessing they need replacing. All the research I have doen seems that the bearings should be tight with no play and I do believe mine has some play.

Lateral play should be limited but still present. Vertical should be non-existant. Low compression indications wouldn't come from the bottom end, they would show in the P/C area. Of course you should have a good look at the seals and bearings now that it's open but we need more info as to what your intentions and financial considerations are for the saw.

 

[armytaco]

No play from flywheel or pto just some side to side on the rod....thanks

Cannot get the wrist pin out. Pulled the c clip on both sides and it catches right where the clips would be. Any tips?

Know the compression comes from the top end just wanted to check the bottom while I was doing it.

 

[blsnelling]

The rod will move side to side on a brand new crank. No radial play on all crank bearings is important. The wrist pin will tap right out once the clips are removed.