EGO CS1600 & CS1604 Chain: Size, Part Number and Fitting

One bar, one chain

The CS1600 and CS1604 are the same saw. The CS1604 is the kit with a 5.0Ah battery and charger. Both run a 16” AG1600 bar and AC1600 chain.

EGO’s CS1600 manual lists only that pair (p. 18) and says to use the listed combination when you replace either part (p. 36). EGO’s AC1600 page calls it the only chain EGO recommends for CS1600 models.

The manual’s spec table gives the pitch as 3/8” (p. 17). EGO’s product pages are more exact: “3/8 in. Low Pro”. That matters when you buy a non-EGO chain. Oregon treats 3/8” Low Profile and standard 3/8” as separate pitches (how to read chain numbers). Check all three numbers on the box: 3/8” low-profile, .043” gauge, 56 drive links.

Changing the chain

The side cover is held by one knob, and tension is set with a knob, so you don’t need a wrench. From EGO’s manual (pp. 36–38):

1. Remove the battery and let the saw cool. Tighten the oil tank cap.
2. Lay the saw on its side, side cover up. Turn the side-cover knob counterclockwise and take the cover off.
3. Turn the chain-tensioning knob toward the front handle as far as it goes. Lift off the bar and chain, and take the old chain off the bar.
4. Lay the new chain out flat and straighten any kinks. Fit the drive links into the bar groove, leaving a loop at the back of the bar.
5. Put the loop around the drive sprocket. The arrows on the chain must point the same way as the arrow molded into the housing. If they don’t, flip the bar and chain over together.
6. Slide the bar slot over the alignment flanges. The tension-adjusting pin must go into the lower hole in the tail of the bar.
7. Refit the side cover and tighten the knob only lightly, so the bar can still move.
8. Turn the tensioning knob clockwise until the chain sits snug with the drive links in the groove. Then set the tension as below.

This is also the time to look at the drive sprocket. EGO says to have it replaced by a service technician if it shows wear or damage (p. 40).

Setting tension

Hold the bar tip up and check for sag under the bar. Turn the tensioning knob one turn clockwise and check again until the sag is gone. Then, still holding the tip up, tighten the side-cover knob firmly (p. 38).

The chain is right when it is snug with no sag underneath but still turns by hand without binding. If it won’t turn, loosen the side-cover knob a little, back the tensioning knob off one turn, lift the tip and tighten again.

A new chain stretches, so check it often at first. Set tension on a cold chain. In use, the drive links of a warm chain will hang about 1.3 mm out of the groove. A chain tightened while warm may be too tight once it cools (p. 39).

The saw also has a chain-tensioning screw that you can turn with a slotted screwdriver for fine adjustment (p. 21).

When a new chain doesn’t fix it

EGO’s troubleshooting table (p. 47) lists the usual causes when the saw cuts badly or the bar runs hot and smokes:

• Chain on backwards. Check the arrows against the housing arrow.
• Chain not in the bar groove. Refit it.
• Dry chain. The oil tank holds 5 oz. Check the window and refill with bar and chain oil. EGO says to fill the tank before first use, because the saw ships without oil (pp. 23–24).
• Too tight, or debris in the groove. Re-tension, and clear the groove.

Then check the bar (p. 44). Replace it if the rails are worn so the chain leans over, or if the bar is bent, cracked or the rails are spread. Small burrs on the rails can be filed smooth. Turn the bar over now and then to spread the wear. Grease the nose sprocket weekly with chain oil through the lubricating hole.

Sharpening

EGO’s manual (pp. 41–43) asks for a 4.5 mm round file in a file holder. Keep the file level with the top plate, at a 30° angle to the chain. File from the middle of the bar, all left-hand cutters from one side, then all right-hand cutters from the other, and keep every cutter the same length.

Check the depth gauges each time you file. EGO’s clearance is 0.6 mm; use a flat file and a 0.6 mm depth-gauge jointer.

If the cutters have hit nails or stones, or the chain has cut through mud or sand, EGO says to have it sharpened by a service technician (p. 40).