Makita BUC121 Instruction Manual

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Contents

17MAINTENANCECAUTION:• Always be sure that the tool is switched off and the bat-tery cartridge is removed before attempting to performinspection or maintenance.• Always wear gloves when performing any inspection ormaintenance.Sharpening the saw chainCAUTION:• Always remove the battery cartridge and wear safetygloves when performing work on the saw chain.Sharpen the saw chain when:• Mealy sawdust is produced when damp wood is cut;• The chain penetrates the wood with difficulty, evenwhen heavy pressure is applied;• The cutting edge is obviously damaged;• The saw pulls to the left or right in the wood. The rea-son for this behaviour is uneven sharpening of the sawchain, or damage to one side only. (Fig. 18)Sharpen the saw chain frequently, but remove only alittle material each time.Two or three strokes with a file are usually sufficient forroutine resharpening. When the saw chain has beenresharpened several times, have it sharpened in a MAK-ITA specialist repair shop.File and file guiding• Use a special round file (optional accessory) for sawchains, with a diameter of 4 mm, to sharpen the chain.Normal round files are not suitable.• The file should only engage the material on the forwardstroke. Lift the file off the material on the return stroke.• Sharpen the shortest cutter first. The length of this cut-ter is then the gauge dimension for all other cutters onthe saw chain.• Guide the file as shown in the figure. (Fig. 19)• The file can be guided more easily if a file holder(accessory) is employed. The file holder has markingsfor the correct sharpening angle of 30 ° (align the mark-ings parallel to the saw chain) and limits the depth ofpenetration (to 4/5 of the file diameter).Guide the file as shown in the figure. (Fig. 20)• After sharpening the chain, check the height of thedepth gauge using the chain gauge tool (optionalaccessory).• Remove any projecting material, however small, with aspecial flat file (optional accessory).• Round off the front of the depth gauge again.• Wash away dust and particles from saw chain afteradjusting the height of depth gauge.Cleaning guide bar (Fig. 21)Chips and sawdust will build up in the guide bar groove,clogging it and impairing oil flow. Always clean out thechips and sawdust when sharpening or replacing the sawchain.Cleaning the oil filter at the oil discharge holeSmall dust or particles may be built up in the oil filter atthe oil discharge hole during operation.Small dust or particles built up in the oil filter may impairthe oil discharge flow and cause an insufficient lubrica-tion on the whole saw chain.When a poor chain oil delivery occurs at the top of guidebar, clean the filter as follows.Remove the battery cartridge from the tool.Remove the sprocket cover and saw chain from the tool.(Refer to the section titled “Installing or removing sawchain”.)Remove the push nut using a slotted bit screwdriver witha slender shaft or the like. (Fig. 22)Take the filter out of the chain saw and remove small dustor particles from it. When the filter is too dirty, replace itwith a new one. (Fig. 23)Insert the battery cartridge into the tool.Pull the switch trigger to flow built-up dust or particles offthe oil discharge hole by discharging chain oil. (Fig. 24)Remove the battery cartridge from the tool.Insert the cleaned oil filter into the oil discharge hole.When the filter is too dirty, replace it with a new one.(Fig. 25)Insert the push nut with its correct side facing up asshown in the figure into the oil discharge hole to securethe filter. When the filter cannot be secured with a disfig-ured push nut, replace the push nut with a new one.(Fig. 26)Reinstall the sprocket cover and saw chain on the tool.Replacing the sprocket (Fig. 27 & 28)Before fitting a new saw chain, check the condition of thesprocket.CAUTION:• A worn sprocket will damage a new saw chain. Havethe sprocket replaced in this case. The sprocket needto be installed so that it always faces as shown in thefigure.Always fit a new locking ring when replacing thesprocket.Replacing carbon brushes (Fig. 29 & 30)Remove and check the carbon brushes regularly.Replace when they wear down to the limit mark. Keepthe carbon brushes clean and free to slip in the holders.Both carbon brushes should be replaced at the sametime. Use only identical carbon brushes.Use a screwdriver to remove the brush holder caps. Takeout the worn carbon brushes, insert the new ones andsecure the brush holder caps.Storing toolClean the tool before storing. Remove any chips andsawdust from the tool after removing the sprocket cover.After cleaning the tool, run it under no load to lubricatethe saw chain and guide bar.Cover the guide bar with the scabbard.Remove oil from the oil tank to empty it and place thechain saw with the tank cap facing upward.To maintain product SAFETY and RELIABILITY, repairs,any other maintenance or adjustment should be per-formed by Makita Authorized Service Centres, alwaysusing Makita replacement parts.