How to replace a power cord on a B&D 7340 type 2 circular saw?

All of Porter-Cable's circular saws have model numbers starting with a 3. Assuming your saw is a 346, Porter-Cable's part number for that cord is 330079-98. If your model number isn't 346 or you can't get that part number, most any nine to twelve foot 14-2 power cord will work on your saw.

If the saw is tripping breakers, either you are trying to run the saw on a circuit that can't handle the amps the saw needs to run or something is wrong with the saw that is making it draw more amps than it should.
Power supply: You should be on a 15 amp circuit or higher for this saw. Popping breakers can also be caused by using long or low guage extension cords or a low guage power cord on the saw. The saw should have a 14 guage power cord on it and extension cords should not be lower than 12 guage if 50 feet long.
Saw: You've already replaced the cord & switch, if the brushes are OK, look to the mechanics of the saw. The blade should turn freely and smoothly by hand with the saw unplugged. Things to look for are a lack of lubrication in the transmission, binding or broken gears in the trans and binding or seized bearings on the armature or worm gear set. Also, a dull blade forced through wood will also cause the saw to be overworked and draw enough power to trip breakers.

Go to
http://www.ereplacementparts.com/black-and-decker-7390-type-circular-saw-parts-c-4167_4252_12157.html

Things to check: With the saw running, safely grab the cord by the boot and pull and twist it around. This is where a break frequently occurs inside the cord and when the saw is held in certain positions the break will either open or close. If the cord's OK, unplug the saw and remove the brush caps and check the brushes. If the brushes are less than 1/4" long or the springs are burnt or broke they won't make good contact with the armature. If the cord & brushes are OK your next recourse is to replace the switch (Makita PN 651172-0).

Remove the part of the handle over the switch and have a multi meter handy. Plug the cord in and test for voltage where the cord goes into the switch. No power, replace the cord; power, go on. Have someone hold the swtich on and test for voltage coming out of the switch. No power, replace the swtich; no power, go on. Check the condition of the brushes and brush springs. They have to be in good contact with the armature to work properly. If the brushes are OK, you may have a problem with the armature or field. These are usually checked at a service center with equipment most people don't have. If you got this far and haven't found the problem, it may be better to get a new saw.

you can replace it your self . you can cut cord shorter and put on a new plug. @ home depot you can replacement parts

Make your own. If you cut through the cord by accident you can go down to your local hardware store and buy a piece of wire that is the same gauge as the one on the saw. Get a standard plug end too and wire it up the same way the saw is wired. You can splice into the existing wire off the saw, just make sure you use plenty of electrician's tape and that the wires are insulated from each other.

there should be screws on the housing to open up to the cord connections...and there are screw type connectors to disconnect the old cord and connect the new cord

If the cord needs replacing because of a defect return it to Sears. Craftman tools are gauranteed virtually forever. I return a circular saw a few years ago agter useing it fo over 5 years and they replaced it, no questions asked.

Cordless tools lose power as the battery drains, while corded tools deliver reliable, consistent performance with unlimited run time. Corded reciprocating saws range from less than 5 amps to 15 amps or more, with more than 10 amps providing optimal power for heavy-duty commercial use.