MAINTENANCE

CHAIN TENSION

See Figures 13 - 14.

WARNING:

To avoid possible serious injury, never touch or adjust the chain while the engine is running. The saw chain is very sharp; always wear protective gloves when performing maintenance to the chain.

nStop the engine before setting the chain tension. Make sure the guide bar nut is loose to finger tight, turn the chain tensioning screw clockwise to tension the chain. Refer to Replacing the Bar and Chain for additional information.

NOTE:  A cold chain is correctly tensioned when there is no slack on the underside of the guide bar, the chain is snug, but it can be turned by hand without binding.

nChain must be re-tensioned whenever the flats on the drive links hang out of the bar groove as shown in figure 13.

nDuring normal operation, the temperature of the chain will increase. The drive links of a correctly tensioned warm chain will hang approximately .050 in. out of the bar groove, as shown in figure 14.

NOTE: New chain tends to stretch; check chain tension frequently and tension as required.

CAUTION:

Chain tensioned while warm, may be too tight upon cool- ing. Check the “cold tension” before next use.

REPLACING THE BAR AND CHAIN

See Figures 15 - 20.

WARNING:

To avoid possible serious injury, stop engine before re- placing the bar, chain, or performing any maintenance operation.

nRemove the bar nut and drivecase cover.

nThe bar contains a bar stud slot that fits over the bar stud. The bar also contains a chain tensioning pin hole which fits over the chain tensioning pin.

nPlace the bar onto the bar stud so that the chain tensioning pin fits into the chain tensioning pin hole.

nFit the chain over the sprocket and into the bar groove. The cutters on the top of the bar should face toward the bar tip, in the direction of the chain rotation.

nReplace the drivecase cover and install the bar nut. Tighten the bar nut finger tight only. The bar must be free to move for tension adjustment.

nRemove all slack from chain by turning the chain tensioning screw clockwise, assuring that the chain seats into the bar groove during tensioning.

nLift the tip of the bar up to check for sag. Release the tip of the bar, and turn the chain tensioning screw 1/2 turn clockwise. Repeat this process until sag does not exist.

nHold the tip of the bar up and tighten the bar nut securely.

nChain is correctly tensioned when there is no slack on the underside of the bar, the chain is snug, but it can be turned by hand without binding.

NOTE: If chain is too tight, it will not rotate. Loosen the bar nut slightly and turn adjusting screw 1/4 turn counter- clockwise. Lift the tip of the bar up and retighten bar nut.

IDLE SPEED ADJUSTMENT

See Figure 21.

If the chain turns at idle, the idle speed screw needs adjusting on the engine. Turn the idle speed screw counterclockwise to reduce the idle RPM and stop the chain movement. If the saw chain still moves at idle speed, contact a service dealer for adjustment and discontinue use until the repair is made.

WARNING:

The saw chain should never turn at idle. Turn the idle speed screw counterclockwise to reduce the idle RPM and stop the chain, or contact a service dealer for ad- justment and discontinue use until the repair is made. Serious personal injury may result from the saw chain turning at idle.

AUTOMATIC BAR AND CHAIN LUBRICATION

See Figure 22.

nUse Premium Bar and Chain Lubricant. It is designed for chains and chain oilers and is formulated to perform over a wide temperature range with no dilution required.

nRemove the cap and carefully pour approximately 8 oz. of bar and chain lubricant into the bar lube reservoir.

nReplace the cap and tighten securely.

nCheck and refill the bar lube reservoir every time the engine is fueled.

NOTE:  Do not use dirty, used or otherwise contaminated lubricant. Damage may occur to the oil pump, bar, or chain.

CHAIN MAINTENANCE

See Figure 23.

For smooth and fast cutting, the chain needs to be main- tained properly. The following conditions indicate that the chain requires sharpening: 

11 — English

Page 14 Page 16
Page 15
Image 15
Ryobi RY52907, RY52604 Chain Tension, Replacing the BAR and Chain, Idle Speed Adjustment, Chain Maintenance
Page 14 Page 16

RY52907, RY52604 specifications

Ryobi has carved out a prominent niche in the world of outdoor power equipment with its lineup of string trimmers, including the RY52604 and RY52907 models. Both of these tools are designed to cater to the needs of homeowners and gardening enthusiasts, offering a potent blend of performance, convenience, and innovative technology.

The RY52604 model stands out with its robust 26cc engine, providing ample power for tackling a variety of landscaping tasks. Its lightweight design allows users to operate it effortlessly for extended periods, reducing user fatigue. The trimmer features a split shaft design, enabling easy storage and transport. Additionally, it is equipped with a 17-inch cutting width, ensuring quick trimming of large areas while its bump feed head simplifies line advancement, allowing for effective and efficient use.

In contrast, the RY52907 is powered by a remarkably efficient 30cc engine, lifting the bar on performance. This model is particularly known for its reduced vibration technology, which enhances user comfort during operation. The RY52907 also sports a generous 18-inch cutting width that empowers users to cover more ground in less time. One of its standout features is the innovative easy-start system, which helps to ensure quick and reliable starts with minimal effort.

Both models boast advanced features, such as anti-vibration handles for improved user comfort and ergonomic designs that promote a natural grip. They come equipped with durable, dual-line auto-feed heads, allowing users to maintain optimal cutting performance without the hassle of manual line adjustments. These string trimmers are designed with durability in mind, utilizing high-quality materials that withstand the rigors of outdoor use.

In terms of technology, both Ryobi models incorporate cost-effective and environmentally-friendly 2-cycle engines that combine power with fuel efficiency. The addition of lightweight components not only enhances portability but also reinforces the user’s ability to perform various trimming tasks with relative ease.

In summary, the Ryobi RY52604 and RY52907 string trimmers exemplify power and user-centered design. With advanced features and innovative technology, they cater to the diverse needs of garden enthusiasts, whether for simple yard maintenance or more extensive landscaping projects. Their reputation for reliability, combined with the brand's commitment to customer satisfaction, makes Ryobi a go-to choice for outdoor power equipment.
Top Page Image Contents