Hot rod Poulan 3400

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SamT1

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So what would you do to really make an old 3400 run? I know the exhaust port is horribly choked from the get go. But what do I need to do for timing?

Base gasket delete, mill it down if needed.
Muffler of course
Ignition advance +2
Open exhaust and transfers a little
I have been just smoothing intake bends and stuff, but maybe I should build up the intake with epoxy and get the volume way up?

I’m unsure what to do with the timing. I’ve never changed the timing on purpose! I want the thing to scream, I have a couple jugs I can screw up and if I ruin em I’d rather have a bigger jug anyway!
I’m going to build this saw to ride in my tool box for impromptu wood cutting. It’s going to get beat up and abused. If it lives for 100 cords that would be a good deal.
 
I have 4 3700's and will hopefully see some good info here eventually. do you know if the timing needs advancing ?
I'm modding my 3.7 one thing at a time. Started with muffler mod then smoothing the transition from carb to intake port. Next will be BG delete then bump the timing a little. 20191107_090706.jpg muffler mod20200211_155627.jpg intake block smoothed for better flow.
I'm doing it one thing at a time to see what shows the most gains without altering the ports.
 
The best thing you can do with this saw is increase compression. The stock 3400/3700 Poulan had the lowest compression I've ever seen on a 2-stroke,comp. was about 110 psi on a Snap-on tester. Hopefully there is lotsa squish-gap you can take up on this motor with a thinner gasket,that's what I did with the one I tested.
They were a great running saw,none the less...
Raising the ex. port unfortunately results in less compression.
 
The best thing you can do with this saw is increase compression. The stock 3400/3700 Poulan had the lowest compression I've ever seen on a 2-stroke,comp. was about 110 psi on a Snap-on tester. Hopefully there is lotsa squish-gap you can take up on this motor with a thinner gasket,that's what I did with the one I tested.
They were a great running saw,none the less...
Raising the ex. port unfortunately results in less compression.
20200221_184532.jpg just pulled the base gasket on mine. Haven't had a chance to run it. Theres plenty of room to machine the base just not ready to try that today.
 
Well first pull the base gasket,then test comp. with an accurate gauge,then check your squish clearance with soft lead solder,should not be less than .020".- - What does your motor read now for comp. psi, what is your squish gap now?
Hopefully comp.is in 120 to 150 psi range. Don't drop the cyl. anymore than you have to,you lose high speed power in favor of low speed.
After deleting base gasket I would look to making muffler less restrictive,modifying airbox to allow more air to carb, if in. and ex. ports have room on piston skirt to be widened 1mm each side I would do that too.
 

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