The venerable XR600 is arguably one of the toughest off-road motorcycle engines ever trumped-up. While the unmarried cylinder four-strokes can select a piece of abuse, compatible any other engine, they can wear outside or gap. Engine rebuilding is primarily approximately replacing or resurfacing worn bearing surfaces -- including bearings in the engines. When rebuilding the Honda XR600 most crowd catch the befalling to upgrade the engine with performance parts, moreover to recent bearing surfaces. It's important that any performance parts be matched to work in unison, such as new pistons and cams. The most common rebuild on single-cylinder motorcycles such as the XR is to rebuild the top end of the engine from the connecting rod up.
Instructions
1. Set your motorcycle on on a shop stand. Turn off the fuel petcock. Remove the seat, gas tank, exhaust and carburetor. To hold the carburetor out of the way, you can remove the carburetor cable, noting the cable adjustment beforehand. Digital photographs are helpful throughout the process.
2. Unplug the spark plug.
3. Remove the valve cover bolts. The valve cover on the XR600 is a cast magnesium case that looks very similar to head fins. Set it aside on a shop rag.
4. Carefully rotate the engine using the kick-starting lever until you can see the master link in the timing chain. Thread the end of a long zip tie through one link of the chain on both sides of the cam sprocket so the chain cannot fall down into the case. Back the master link off with a flat screwdriver. Be careful not to drop it. Unlink the chain.
5. Remove the head bolts. Carefully remove the head. You may need to apply a little pressure sideways to get the gasket seals to release. Lift the head off and over the piston. When the cylinder is nearly free of the piston, wrap a heavy shop towel around the piston skirts so that no damage occurs when the piston clears the cylinder.
6. Remove the wrist pin and the piston.
7. Remove the valve springs and valve assemblies from the head with a Honda valve tool.
8. Remove the cams from the head.
9. Clean each of the mated head surfaces: the engine block, cylinder bottom and top, heat bottom and top, and valve cover. Use a scraper and gasket solvent.
10. Take the entire top end to a motorcycle machine shop to bore the cylinder and head to your kit's specifications. Depending on your rebuild and kit, the machinist at the shop may also machine your valve ports. The machinist should also make sure that the rings are gapped properly.
11. Install the new piston, wrist pin and rings. You may need a special tool for ring installation.
12. Install the gasket seal and/or the gasket in the rebuild kit to the engine block.
13. Wrap the piston skirts again. Use a ring compression tool to slide the newly machined cylinder over the new piston.
14. Tighten the cylinder bolts, then gradually torque them to factory torque specifications.
15. Replace the cams, rockers and valve springs in the head.
Re-torque the head to factory specifications.17.Refasten the timing chain and master link.18. Turn the engine by the kick starter, slowly, several revolutions with the spark plug wire still removed.16. Place the head gasket on the deck of the combustion chamber. Replace the head, threading the zip-tied timing chain through the timing shaft.
Adjust the valve lash on each valve to the specifications of the new cams using a feeler gauge.
19. Replace the valve gasket and cover.
