Yamaha Star 650 Valve Adjustment - Checking and Adjusting PART 1 of 2

** NOTICE 14:50 I read out a value in my native imperial which may cause some confusion, "6 passes but not 7" being in thou/in not mm. As indicated below .006 = .150mm **

Today we will be doing the inspection and adjustment of the valve lash on a Star 650, also known as a Vstar 650 or Dragstar 650, depending on where you live. This is an important, labor intensive, and often overlooked critical maintenance item that must be performed on any motor with solid lifters. There must be a prescribed amount of clearance and the margins are small, very small.

An opportune time to do this is any such occasion that the carbs are removed, such as a carb cleaning or rebuild. The 650, as opposed to the 1100 still requires much more faux chrome removal even after that just to get to the tappet covers. Consider this when you think how much your mechanic charges per hour to do this job. Its not a quick job. It can't possibly cheap. Maybe someone could tell me though.

Even with the chrome covers removed, and one ignition coil, each cylinder has its own side cover for the cam to be removed allowing for a particular dot to be aligned to a point on the head. This dot moving when the engine turns through yet two more covers removed to being this into position. This having to line up and corresponding to the correct marking on the crank through the inspection hole, depending on the cylinder.

The final test of this alignment is the wiggling of the tappet, there should be audible play as whey wiggle ever so slightly up and down. If not, you either messed up, or they are really in a bad way. Confirming this, and as luck would have it, three of my four were on the outer limits of acceptability. This means they were good. But I like them in the middle. So, adjust them I did. This involved the usual technique with a feeler gauge, a hex key and a box wrench. Lock nut is 10 ft/lbs

Satisfied with the new clearance, I clean the tappet cover, mating surface and put the cover back on. No need to keep it off and risk contamination. The screws are 7 ft/lbs. On the exhaust values, paper towel should be used under them before opening as some oil will leak out. This is especially true for the front exhaust value. The measurement is one value less than the first gauge that doesn't fit.

INTAKE .004in .102mm
EXHAUST .006in .150mm

Finishing the front cylinder tappets brings an end to part one. Part two continues with the rear cylinder and reassembly.