Ms200t--to base gasket or not...

[72thing]

I'm redoing the top end on my saw with used OEM cylinder and meteor piston/caber rings. Will I see any appreciable gains by only eliminating the base gasket? I'm not planning on any port work. The new base gasket measures .019" and the squish is .042". I can get the squish to .023" by ditching the gasket. Should I or shouldn't I? Any major downsides? I'm already leaving out the spark arrestor. Ya'll don't flame me too hard. I've did a lot of reading, but this is my first time rebuilding the top end on a saw. But I do like more power.

Sent from my C771 using Tapatalk 2

 

[big t double]

I run mine with no base gasket...seems to run strong but then again they are strong runners stock...where's the pics!! And i was wondering...Is your screen name in reference to the vw safari?

 

[Arrowhead]

Absolutely ditch the gasket!! I ported my 200T, without the gasket I think I'm at .019 squish.
Make sure you use a sealant on the base that is fuel proof. I use Motoseal by Permatex. I love that stuff.
You'll gain some compression and a little torque. You'll notice a difference.

 

[72thing]

Thanks for the quick replies. Yeah, I'm not quite ready to do port work, but I figured eliminating the gasket might pick up a little more power. Of course, not having a scored piston/cyl will help as much as anything.

Big t--My username refers to my '72 Chevy C10 trail truck on 1-ton axles and 42" Swampers. One day about 12 yrs or so ago, my friend's dad looked out the window and saw my old junky looking truck, and said "What the heck is that thing?" So the name Thing sorta stuck.

Thanks! and I plan to start another thread with the reassembly of the saw. I just don't have time right now to upload all the pics and write it up.

 

[lone wolf]

Thanks for the quick replies. Yeah, I'm not quite ready to do port work, but I figured eliminating the gasket might pick up a little more power. Of course, not having a scored piston/cyl will help as much as anything.

Big t--My username refers to my '72 Chevy C10 trail truck on 1-ton axles and 42" Swampers. One day about 12 yrs or so ago, my friend's dad looked out the window and saw my old junky looking truck, and said "What the heck is that thing?" So the name Thing sorta stuck.

Thanks! and I plan to start another thread with the reassembly of the saw. I just don't have time right now to upload all the pics and write it up.

Vac pressure test while apart you said it had a scored cyl before right? Find out why!

 

[72thing]

Vac pressure test while apart you said it had a scored cyl before right? Find out why!

I bought the saw running, but it turned out to have a toasted top end, badly scored. I press. tested it to 10 psi and after 10 min it lost about 1/2 psi. I vacuum tested it to 15 in/Hg and after 10 min it went down to about 14 in/Hg. I rotated the crank during each test. I mainly wanted to test the oil seals and they passed. At the start of testing, I couldn't get the intake boot to hold pressure at the head (yes I did have the plastic ring on it). I finally resorted to putting a few wraps of electrical tape around the boot to increase the OD and used a steel clamp off a MS440. This seemed to do the trick.

I think most of the damage on the topend was from carbon. I've never seem so much carbon buildup. There was a least a 1/16" or thicker in the exh port.

I left the base gasket off and sealed it with some purple CNH (Case New Holland) anaerobic flange sealant. I think it'll work fine as it worked great sealing the axleshafts to the bearing hubs on my 2500 Dodge and it has hot gear dope running around it all the time.

 

[VINIFIREWOOD]

I bought the saw running, but it turned out to have a toasted top end, badly scored. I press. tested it to 10 psi and after 10 min it lost about 1/2 psi. I vacuum tested it to 15 in/Hg and after 10 min it went down to about 14 in/Hg. I rotated the crank during each test. I mainly wanted to test the oil seals and they passed. At the start of testing, I couldn't get the intake boot to hold pressure at the head (yes I did have the plastic ring on it). I finally resorted to putting a few wraps of electrical tape around the boot to increase the OD and used a steel clamp off a MS440. This seemed to do the trick.

I think most of the damage on the topend was from carbon. I've never seem so much carbon buildup. There was a least a 1/16" or thicker in the exh port.

I left the base gasket off and sealed it with some purple CNH (Case New Holland) anaerobic flange sealant. I think it'll work fine as it worked great sealing the axleshafts to the bearing hubs on my 2500 Dodge and it has hot gear dope running around it all the time.

As long as that CNH sealant is gas resistant you should be fine. The gas eating up the sealant will undo everything you just did.

 

[z71mike]

Ethanol resistance is the important part here. Silicone don't like alcohol. Go get a tube of Yamabond or Motoseal.

 

[72thing]

Ethanol resistance is the important part here. Silicone don't like alcohol. Go get a tube of Yamabond or Motoseal.

From what I've found, a lot of people have used this CNH sealant, which is rebadged Loctite 515, on fuel system parts. It is not a silicone based product and I won't run ethanol fuel in any of my power equipment. But I guess only time will tell! Thanks for the advice.