Adjusting valves on a 87 to 98 Big Bear.
Check and adjust valve clearance with the engine cold. The exhause valve is located at the front of the engine and the intake is located at the back next to the carburator.

1. Remove the seat front rack and front fenders.
2. Remove fuel tank.
3. On models equipped with the range selector lever mounted on the left hand side of the engine, remove the mounting screws and remove the selector cover.
4. Remove the ignition timing window plug and O-ring. Located just behind where you manual starter handle is.
5. Remove the cylinder head side cover and O-ring
6. Remove the exhaust and intake valve covers and O-rings. 87 and 88 models have a decompression
assembly mounted on the exhaust valve cover.
7. Remove the spark plug, this will make the engine easier to move by hand.
8. The engine must be set to top dead center on its compression stroke before checking and adjusting valve clearance. With the manual starter removed
Place a wrench on the crankshaft starter pulley,
turn the crankshaft counter clockwise and align the
camshaft sprocket index mark with the cylinder head mark. There is a little point in the top of the head which points down  align that with the straight line on the sprocket.
Now check that the T mark on the rotar is aligned
with the crankcase index mark. there is a T on the rotar that has to be aligned with the line on the crankcase. If these marks are not aligned, turn the crankshaft one revolution counterclockwise and align the rotar T mark with the crankcase mark.
When the camshaft sprocket and rotar marks are properly aligned, both rocker arms will have a valve clearance, indicating that both intake and exhaust valves are closed. Check by moving each rocker arm
by hand. There should be some side movement.
9. Check clearances of both intake valve and exhaust valve by inserting a flat feeler guage between the rocker arm pad and the valve stem.
The Intake clearance is 0.06 - 0.10 mm ( 0.002-0.004
in) The Exhaust is 0.16 - 0.20 mm ( 0.006 - 0.008 in)
10. To correct the clearance use a 10 mm wrench
and back off the valve adjuster locknut. Use a 4 mm
wrench and turn the adjuster in or out so there is slight resistance felt on the feeler guage. Hold the adjuster to prevent it from turning and tighten the lock nut to 11 ft- lbs. Recheck the clearance to make sure the adjuster did not slip when the locknut was tightened. Then put everything back together the way it came apart and your done.
Timing Chain Tip             
When checking a timing chain you should hold it out in the air on its flat ( pins in the chain facing up and down) and if the chain drops down on the other end its time for a new one.
This shows that the pins in the chain are weak Causing the chain to droop down.
           Secondary Clutch Adjustment
Loosen the lock nut on the adjuster. Then turn the clutch adjust screw counterclockwise until resistance is felt, then stop. Then turn the screw 1/8 of a turn clockwise then stop. Hold the adjustment screw and tighten the lock nut. Then take it for a test ride and and make sure the clutch is working right.
Connecting Rod Play
When checking for play in a connecting rod you should have the piston and wrist pin removed. Stick you index
finger through the top eye and try to move the ROD
left to right then try  up and down. There should be very little movement if any at all.
Installing Bearings
Before installing bearings you should freeze them overnight to make them fall in place.