Yamaha Star 650 valve adjustment video

4096 Views 2 Replies 2 Participants Last post by SemiFast, May 10, 2019

jcrubin

Discussion Starter · May 6, 2019 (Edited by Moderator)

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.

PART 1 of 2
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jcrubin

Discussion Starter · #2 · May 10, 2019

We continue here with 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. Having just finished the front exhaust value, the inspection cover for the cam is closed after both the cover and mating surfaces are cleaned and the O ring inspected. This, as well, torques to 7.5 ft/lbs.

The process would then continue to the rear cylinder again having to remove the cam cover for the rear and rotate the engine, this time to the TI mark. On this side, one can see the dot on the cam as the engine is rotated making it somewhat easier. Aside from this, the adjustment on the valves for the rear remains identical if not slightly easier on the exhaust side than that of the front.

Having completed the rear adjustment, all chrome pieces are first washed with dish detergent and then using windex and chrome polish, dressed to a shine. Before installing them however, the spark plugs have miles of room for installation and should be added first. Make sure as the covers are installed that the pretty hex screws are used on the top covers; don't make the same mistake I did.

With all of the covers back on, be sure to re-add the hose clip for the breather, and then remount the rear ignition coil. A final cleaning to remove fingerprints removes all work evidence. A successful job awaiting a carb reinstallation.

PART 2 of 2

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SemiFast

· #3 · May 10, 2019

Very good video. Thanks for posting. Good, free information for the masses.
I'm sure it will be very helpful for riders that want to learn how to service the own V-Star.

To make the job go a little faster you could just loosen the cables going to the carburetors and only suspend them above the frame. You may still need to remove the choke cables, can't remember right now.
Another trick. Remove the tappet covers before turning the crankshaft to find TDC.
As you turn the flywheel you can watch the valve action to determine if you are moving to TDC compression or TDC on overlap. This allows you to avoid removing the cam sprocket cover in order to see that you are at TDC compression.
Also, if you remove the spark plugs you can watch (using a flashlight) the piston come up to TDC as a way to verify that you are looking at the correct marks on the flywheel for the front or rear cylinder.

A fair "shop flat rate" for doing a valve lash adjustment on the V-Star 650 is around 2.0 Hr.
It would be a good idea to do a carb synchronization after the handling the carburetors and doing the valve lash adjustment.

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