MS200T top end replacement with lots of pics

[72thing]

I finally got around to replacing the badly scored topend on my MS200T and promised I'd take some pictures.
I got a used cylinder that had been cleaned up--thanks to Ted! (big t double)


Saw broken down




New piston


Nice parts



Installed

 

[72thing]

Circlips installed


Rings


Rings compressed (this was before I decided to ditch the base gasket)


Here's the anaerobic flange sealant I used (feedback from folks on interweb say it holds up well to fuel, but time will tell)


Cylinder installed


Looks nice


~.030 squish. Thought it would be a little less, but it'll work.

Block-off plate for exhaust made out of scrap 1/4" plate with bicycle innertube for gasket


Installed

Another piece of innertube to block off intake

 

[72thing]

Carb bolted on over gasket (notice JB Weld over accel pump circuit)

Under pressure

When I tried to pressure test it, I had major leaking where the intake boot went on the cylinder spigot, even with the plastic piece over the boot. Apparently, it doesn't seal very well. And the intake boot was in perfect condition and still very flexible with no nicks or tears. So...I had to rig this ugly stuff up. I used a clamp off an 044, but had to put a few wraps of tape over the boot to increase the OD. After I cinched up the clamp, it held good enough to do the test.

After 10 minutes at 10 psi, it went down maybe 1/3 psi. That'll do. I also vacuum tested it to 15 in/Hg and it only went down 1 in/Hg after 10 minutes. Pass.


I finished the assembly, set the baseline on the carb, and fired it up. I cut a little bit of wood and then fine tuned the L and set the H to ~13,800. It ran great and had a nice snappy throttle response. This little saw screams! I ran through a tank of fuel and it never missed a beat. After a few tanks, I'll lean it out a little closer to 14,500.

 

[imagineero]

Nice write up. Did you pop a new carb on as well?

 

[72thing]

Nice write up. Did you pop a new carb on as well?

Thanks. No, I just rebuilt the one that was on it and blocked off the accelerator pump circuit with JB Weld. A new carb was way too expensive.

 

[big t double]

looks good!! ive had them leak where yours did also...replacing that square plastic support plate that goes around the boot took care of it....I love them little saws, they just rip.

 

[Raganr]

Nice write up and thank you for taking/posting pictures. I sent my rear handle MS200 to Mastermind to be rebuilt (from split crank case). Randy did an outstanding job and love that saw. Wonder if he left off the base gasket

 

[72thing]

Nice write up and thank you for taking/posting pictures. I sent my rear handle MS200 to Mastermind to be rebuilt (from split crank case). Randy did an outstanding job and love that saw. Wonder if he left off the base gasket

Don't know for sure, but I'll bet he left it off.

looks good!! ive had them leak where yours did also...replacing that square plastic support plate that goes around the boot took care of it....I love them little saws, they just rip.

Looks like I need to price that plastic "clamp" and replace it. For now, I put a small coating of high temp sealant on the boot before I put the clamp on.

 

[big t double]

1129 141 3300 should run you about four bucks from your dealer...ive taken apart a couple 200t's with silicone in that area. if I had a spare id ship it to ya but theyre cheap enough.

 

[72thing]

1129 141 3300 should run you about four bucks from your dealer...ive taken apart a couple 200t's with silicone in that area. if I had a spare id ship it to ya but theyre cheap enough.

Hey thanks again for the advice, Ted. I called and got one on the way. and you were dead on with the price being $4.