139/150-Hour Maintenance, Valve Adjustment

50-Hour Maintenance

Every 50 hours of operation

(more frequently in dusty or dirty conditions):

nRemove and clean the cylinder cover and clean dirt and debris from the cylin- der cooling fins.

nLubricate the gearcase. To perform this operation, first remove the gearcase from the outer tube as follows:

	Gearcase
Outer Tube	Clamp Bolt

Gearcase

Figure 21	Index Bolt

CAUTION!

Do not remove the D-shaped shim washer from the gearcase clamp! The shim washer prevents damage from overtightening the tube clamp screw.

a.Loosen the gearcase clamp bolt.

b.Remove the index bolt from the gearcase.

c.Slide the gearcase out of the tube.

Using a grease gun, pump lithium-base grease (about 10 grams) into the grease fitting on the gearcase until you see old grease being purged from the gearcase (Figure 22). Purged grease will be visible in the outer tube cavity. Clean up excess grease, then reassemble the gearcase onto the outer tube. Make sure the index bolt fits into the hole on the outer tube. Securely tighten both bolts.

	Gearcase
Figure 22	Grease Fitting

Servicing the fuel filter

CAUTION!

Make sure you do not pierce the fuel line with the end of the hooked wire. The line is delicate and can be dam- aged easily.

nUse a wire hook to extract the fuel filter from inside the fuel tank (Figure 23). In- spect the fuel filter element. If it shows signs of contamination from debris, replace it with a genuine Shindaiwa replacement fuel filter element. Before reinstalling the filter, inspect the fuel line. If you discover damage or deterio- ration, the unit should be removed from service until it can be inspected by a Shindaiwa-trained service technician.

Hooked

Wire

Figure 23

Filter Element

139/150-Hour Maintenance

Maintenance after first 139-hours, then every 150-hours thereafter.

nCombustion chamber should be decar- bonized, and the valve clearance should be adjusted. It is highly recommended that this is done by a Shindaiwa-trained service technician.

nReplace the spark plug annually: Use only NGK CMR5H or equivalent resis- tor type spark plug of the correct heat range. Set spark plug electrode gap to 0.024-0.028 inch (0.6 -0.7 mm).

NOTE:

The NGK CMR5H also meets the require- ments for electro magnetic compliance (EMC).

Valve Adjustment

1.Remove cylinder cover, rocker arm cover, and set piston at TDC-compresion.

CAUTION!

nPerforming a valve adjustment incorrectly may cause hard starting and/or can damage the engine.

nIf you are unfamiliar with this engine or uncomfortable with this proce- dure, consult with an authorized Shindaiwa servicing dealer.

2.Loosen adjuster locknut so that the 2.5 mm Allen socket head adjustment screw can turn freely.

3.Insert feeler gauge (.004” for both intake and exhaust) between valve stem tip and rocker arm.

4.Turn adjustment screw (clockwise = tighter, counter-clockwise = looser) until feeler gauge is almost snug. Back

off just enough to allow gauge to slip out with limited resistance.

5.While holding adjustment screw in place with Allen driver, tighten locknut with wrench.

6.Turn engine over several times, and return to TDC-compression. Recheck with proper feeler gauge to make sure clearance adjustment did not change as a result of tightening locknut. Readjust as necessary.

7.Replace rocker arm cover gasket to as- sure proper sealing and install cover.

IMPORTANT!

If new gasket is not available and/or old gasket is not damaged, old gasket may be reused. Never use cracked or dam- aged gaskets!