Is deleting the base gasket generally a safe mod?

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teacherman

Aging out of the insanity...
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for a modern Stihl pro saw? I am leery of the grinding, especially enlarging port openings and disrupting the nikasil cylinder liner. But in general is it safe to just drop the gasket, or does that run a risk of not enough squish room? I've been messing with saws a while, but I'm not much of a modder per se.
 
Generally, yes. Just lightly bolt down the cylinder and check the squish woth a piece of solder stuck through the plug hole. Just be careful that the piston is above the exhaust port when checking. Also use solder somewhere around .025 thickness. Roll piston past TDC, and measure with micrometer. The bigger the solder, the less accurate this method will be.
 
.020 is pretty generally accepted as the minimum safe squish for most applications.
OK, thanks for that. I like the idea of being able to slip it in the plug hole. I heard before you have to unbolt and slip the jug off, and have several little bits of solder on various part of the crown, stuck on htere with grease, then torque it back down and then unbolt it again to check and so forth. Seemed like more of a pain than it's worth that way. I'd have to put in some HeliCoils after a session of that nonsense...
 
I would say the compression ALL depends on where you live. The lower the altitude the higher the compression is. The shape of the combustion area is indeed important. A small amount of compression increase can be a great thing, but if every thing else is perfect it still can cause a loss of power. Higher compression with more advance spark in areas above 4,000 feet would cause performance gain. However at sea level with more compression can produce more torque and less over all power. Rule of thumb more torque means less RPMs. Thanks
 
.020 off the flywheel key is another generally accepted safe mod. Along with a muff mod, those things things make a nice performance boost.
What does this mean? Taking out the key and sanding a sliver off of it, and holding the flywheel counterclockwise with a piston stop in place so it's a degree or so advanced? I turned the flywheel of an 088 back the other way recently because I couldn't start the dang thing, it was snatching the handle out of my hand so much. It did seem a bit loose rotationally, so maybe that's what a previous owner did with it. Maybe it has no gasket...
 
Making the muffler a little larger and opening it up a bit is a pretty safe mod. Advancing the spark a couple degrees via the crank key is another accepted mod, but will produce a bit more heat.
"Seems like a lot of hassle for something that you may not even notice."
I have more saws than most and use them more than most so modding saws is not a big priority. Normal for me is working at 6,000 feet, but as of late 3,500 is normal. So it would be a major hassle to have to go through much retuning for the altitude. Thanks
 
Do those of you that remove base gaskets raise the transfer and exhaust ports at the same time, or do you feel that the increased compression outweighs the loss caused by lowering those ports?
 
Do those of you that remove base gaskets raise the transfer and exhaust ports at the same time, or do you feel that the increased compression outweighs the loss caused by lowering those ports?
I never have, id end up doing more harm than good im guessin haha. Never done the math but probly only a couple degrees of difference, depending on how thick the gasket is
 
To check the Squish correctly you require at least 3 pieces of & I prefer the plastic type checking strip. You may possibly get a fairly accurate reading with a piece at fore/aft 90degrees to the piston pin any less & the piston can & does tilt & gives a false reading & 3 is better the extra one being in the piston centre
 
To check the Squish correctly you require at least 3 pieces of & I prefer the plastic type checking strip. You may possibly get a fairly accurate reading with a piece at fore/aft 90degrees to the piston pin any less & the piston can & does tilt & gives a false reading & 3 is better the extra one being in the piston centre
http://www.plastigaugeusa.com/how.html
 
Seems like a lot of hassle for something that you may not even notice.
Every gasket delete/squish reduced saw I've run is very noticeable. Saw doesn't need a port job to run strong.
A mm coupled with a what the OP wants to do will produce good results
 
It's safe... I've got a dozen saws or so running with the gaskets removed running 5 days a week... It's deffinantly worth it.
 
Every gasket delete/squish reduced saw I've run is very noticeable. Saw doesn't need a port job to run strong.
A mm coupled with a what the OP wants to do will produce good results

It's safe... I've got a dozen saws or so running with the gaskets removed running 5 days a week... It's deffinantly worth it.

This is excellent! It will give me a reason to give a few saws a good cleaning, ones with fully adjustable carburetors.
 
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