Didn't know that the25DA had 2 piston rings, surprised.
dunno how to undo the quote... got 2 micros, red & green, and 2.1/14 craftsman, non cv, yesterday if anyone needs partsYou read my mind. I actually have my eye on another Micro XXV and a 2.3 with a chain brake.
I have too many projects on the go already though.
I have taken a couple of 3800 down to a squish of .023 to .020" and got around 150 psi. If your going through that much trouble and you are going to modify the saw, then widen the intake and exhaust port by a little. Then port match the muffler to the cylinder. Then also clean up the inside of the plastic intake and smooth it out from any casting flaws. Then take the deflector inside the muffler and drill out the holes to a bigger size. Then cut a slit in the muffler on the clutch side of the saw and open it up a little to let the exhaust breathe better. Then you can advance the timing by a couple of degrees by using the mopar Mike method of putting a piece of a penny in the key way slot on the fly wheel. Make sure you turn the fly wheel ccw to advance timing. Then the best modification of all, make sure the chain is really sharp and the rakers set to the correct level. That 3400 will cut like no bodys business.
When you tune the saw just tune it like any other saw. 4 stroking at wot and then 2 stroking when put into wood.
View attachment 366132 Hey guys I've been busy reading past posts in this stickie, lots of useful information from here.
Today I picked up a 3400 for parts. I was quite surprised that the recoil sticker said 61 cc beneath the 3400 Counter Vibe label. I had my hopes up that it was a 3700 top end so I quickly pulled the muffler.....darn, chrome piston! Oh well maybe a 3800... off comes the cylinder.... 46mm bore, doh!! Just a regular old 3400. All is good though, lots of compression, not much blow by on the piston. I wonder why the sticker was screwed up?
Since this cylinder is off, it will be going on the lathe to set the squish and I plan to decrease the radii of the exhaust port. I may widen the intake and exhaust ports slightly, as well raising them to compensate for the cylinder being decked. The transfers will be left alone since I only have a dremel. The intake manifold is getting cleaned up too.
From my modest research, this seems to be the standard "recipe" for novice chainsaw tuners. Almost forgot to mention muffler mod. Anyone have any other pointers?
Sorry for the long winded post and thanks for all top handle pictures, John.
Always the entrepreneur.Little did you know Roger that we no longer have pennies in Canada for the timing change. I saved some though and am selling for $1 each.
Just an idea. I'm sure you have a compression gauge. Maybe try a bit of 2 cycle down in the plug hole, take the gauge off of the hose, screw in the fitting for the plug, connect the gauge hose to a compressor and hit it with some air. Might just be enough to seat the ring where it is grabbing and push it out rather than pulling.I have tried everything to separate this cylinder from the piston with no luckView attachment 365950
Will have to block the ports too- couple pieces of 1/8 sheet anything with a piece of inner tube behind bolted strait to the cylinder. Might be able to use the muffler and carb bolts/screws.Just an idea. I'm sure you have a compression gauge. Maybe try a bit of 2 cycle down in the plug hole, take the gauge off of the hose, screw in the fitting for the plug, connect the gauge hose to a compressor and hit it with some air. Might just be enough to seat the ring where it is grabbing and push it out rather than pulling.
I'm not saying load it up just a quick hit. maybe even one of those harbor freight air nozzles with a rag.Will have to block the ports too- couple pieces of 1/8 sheet anything with a piece of inner tube behind bolted strait to the cylinder. Might be able to use the muffler and carb bolts/screws.
I'm thinking out loud on this.
The S25 CVA is in great shape. One of the 3400's is in real good shape but unfortunately has a plastic clutch cover.Just a heads up. There are a couple nice Poulan's on flea bay right now. A 3300, 3400, Super xxv cv. Take a look.
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