Wish to woods port 2100cd

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terry2tmd

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I have a great piston and cylinder on a messed up crankshaft just laying around I decided I'd like to try my hand at porting it a little and bolting it on to my runner just to see what happens. I want to just widen the intake and exhaust ports I have no interest in raising or lowering ports this is a big saw and I just want to help it breathe a little better.
My main concern is the impulse hole on the left lower corner of the intake port can I grind this out or is the impulse hole important, Grinding that out would really open the intake port up a lot, and I mean a lot!
I also read about cutting the bottom of the piston skirt out at TDC good idea but will it hurt my piston?
How do I decide what is a safe distance to move the transfers to the intake?
I don't just start grinding, I know what I want faster wind up, and a little more torgue in the cut.
Also I am not happy with the stock clutch on this saw where can I get a tougher clutch and sprockets.
 
Just remember that the piston has to "close" those ports, so going wider than the piston skirt may end up with gaps either side which will not be good. 70% of bore dia for exhaust width is a general rule of thumb. And open the muffler to suit. If your going to the trouble of modding it, measure squish and reset aiming for about 0.02 of an inch. you can clean up the casting and help flow a little on the piston windows.
 
I have a great piston and cylinder on a messed up crankshaft just laying around I decided I'd like to try my hand at porting it a little and bolting it on to my runner just to see what happens. I want to just widen the intake and exhaust ports I have no interest in raising or lowering ports this is a big saw and I just want to help it breathe a little better.
My main concern is the impulse hole on the left lower corner of the intake port can I grind this out or is the impulse hole important, Grinding that out would really open the intake port up a lot, and I mean a lot!
I also read about cutting the bottom of the piston skirt out at TDC good idea but will it hurt my piston?
How do I decide what is a safe distance to move the transfers to the intake?
I don't just start grinding, I know what I want faster wind up, and a little more torgue in the cut.
Also I am not happy with the stock clutch on this saw where can I get a tougher clutch and sprockets.

Not only is the impulse hole important.....It's imperative!!! The saw can't run without it.:dizzy:
 
DO NOT GRIND AWAY HE IMPULSE HOLE. It sends air pulses into the diaphragm of the carb so it will pump fuel.
I've ported a half dozen 2100's and have had excellent results. I usually widen the intake and exhaust ports to within .15 inches of the piston skirt, lower the intake 1mm, raise the exhaust 1mm, taper the lower transfers (not all the way to the base of the cylinder), taper the upper transfers toward the intake being careful of the ring ends, clean up the piston windows for better flow, and remove the cylinder gasket and seal it with permatex ultra copper rtv. Let it sit overnight so the rtv can cure, fire it up, tune the carb and have fun:)
Also remove the limiter from the carb and modify the muffler.
 
Thanks guys great advice, you guys are great! I was planning on matching the intake manifold to the intake port I am a little nervious about lowering the intake and raising the exhaust but apparently you have done this before I'll just take my time and work it slow. What do you mean by removing the Carb limiter!
 
Inside the carb there is an rpm limiter. When under no load conditions there is a ball that opens a port that allows fuel to flow through the carb and hold the rpms at 10,500. It is easily blocked with a welch plug cover. I usually tune them to 12,500 to 13,000 rpms.
 
Heck I guess you learn something new everyday thanks for the lesson. This saw at 12,500 would be unreal. I know the ignition I have is supposed to be unlimited. I know it is alot to ask but would you have a picture of this limiter in the carb? Modding this muffler won't be hard at all some one has already stripped it out the only limiting factor I can see in it would be the screen sock, and not portmatching it to the exhaust side. I am used to working on smallblock chevy's and fords these little 2 strokes are a whole new but cool learning curve.
 
Sorry no pics. If you do a search you should be able to find instructions on removing the governor. Usually what I do for the muffler is either bolt on a 288 deflector and screen or have a friend weld a piece of 3/4" pipe to it. When tuned properly at 12,500 to 13,000 rpm these saws will definately put a smile on your face. Add an 8 or 9 pin rim and watch the chips fly:clap:. if you are looking for a stronger clutch, one off of a 394xp will work.
Glad I could help.
 
brucejr,
Don't know your real name, but I owe you big for the help. I like the muffler mod idea. I am trying to get in on a 200 acre burn, and would like to use this old saw. Your help has been great! Thanks!!!!!!
 
One more question where do I find a dealer who sales 8 or 9 pin rims? I have had a hard time finding anything larger then a 7 pin around here.
 
+1 on Bailey's. Not sure if they have a 9 pin in 3/8 though? If this is a work saw I would suggest an 8 pin since they are readily availableat most saw shops.
No problem I'm willing to help out in any way I can. Anymore questions don't be afraid to ask.:):cheers:

Bruce
 
+1 on Bailey's. Not sure if they have a 9 pin in 3/8 though? If this is a work saw I would suggest an 8 pin since they are readily availableat most saw shops.
No problem I'm willing to help out in any way I can. Anymore questions don't be afraid to ask.:):cheers:

Bruce

I Would also go with the 8-pin. What length bar will you be using?
 
With a 28" or larger bar go with the 8 pin. I've run one with a 32" bar and full comp oregon 73lgx. Never bogged down once.
 
The governor, if yours has one, is a big ~5/16" diameter brass screw usually located on the opposite side from the jet screws. They're often threadlocked into place and need a little bit of coaxing to loosen up without stripping the slot. Once you get it out, punch a 1/4" disc from an aluminum can or as mentioned find a small welch plug cover, drop that into the hole, and replace the brass screw. The governor circuit is now effectively blocked and you should be able to tune the saw properly. Now it's the first thing I do on a carb like this; I had a helluva time trying to tune my 181SE before I learned about these governors. They can really be a problem if the little spring inside gets weak, allowing the circuit to open at an even lower RPM. It can make for some hair-pulling troubleshooting if you don't happen to think of it.
 
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For the cutting I do large pine and doug fur I prefer nothing smaller then a 28" bar.

The 8-pin should work fine with this. If you go to a 36" or a 42", I'd carefully watch for any bogging in the cut. If that happens when you apply your normal amount of pressure, try switching to a full-skip chain. I think that that particular saw has enough guts to run an 8-pin with almost any bar you choose. The 7-pin will slow down the chain, even though it results in more torque. For a smaller saw, the 7-pin makes sense, but you are running a big bopper there.
:givebeer:
 
Brad,
Thanks thats a easy fix. I always wondered what the heck that brass screw was about. Like I said learn something new everyday. I think I am gonna stick to the 8 pin, for a couple reasons, the saw handles a 7pin good enough to be a chain stretcher, especially when the oil pump goes bad wich mine did, I am still looking for a good back up for it. That's the other reason I have a hard time getting parts here and if it is a special item like a 9 pin rim, I would probably never get it in. I haven't been able to start this project yet, been working on getting some repairs out of the way. Know anyone interested in a 70e Jonesred, I ended up with one that needs a little work to get running, It's up for sale.
 
9 pins usually cost about 4-5 times what a 8 pin does. Mostly people use them to race with instead of daily use.
 
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