Tight valve lash & uneven factory air screw settings on 1985 VF500

Hello,

I am setting the valves on my 85' VF500 for the first time. It has 21,000 miles & I don't know if the valves have ever been set. All the horror stories I have heard about the valve train on these motors made me tear it down & make sure everything was square.

I tore it all down & the valve lash on both #1 intake valves are less than 0.002" (thats the smallest feeler gauge I have) & might even be zero. Would the valve lash being that far off cause the bike to run shitty?

Also, I went through my carburators & the air screws were still plugged from the factory. I removed the plugs & checked to see where they were set before removing them. Here is what I found:
Cylinder #1 = 1.8 turns
Cylinder #2 = 3.1 turns
Cylinder #3 & #4 = 2.5 turns

The book says 2.5 turns is correct. Why would the factory set #1 & #2 so far from their own factory spec?

I put them back together all set to 2.5 turns. Is that a good idea or should I put them back like I found them?
The valvetrain looks great, the cam lobes have absolutely no wear pattern on the at all. I have built quite a few Pontiac race engines so I know what cam lobe wear looks like. The lobes on both cams are pristine.

Thanks in advance.

 

Glad to hear that the valve train is in good shape. Set the lash, using two feeler gauges, to the specifications in the FSM.

Set the pilot screws out to two turns and go from there. On a side note, the carburetors will also need to be resynchronized using a manometer.

Good luck and let us know how you make out.

 

Those pilot screw plugs may not be factory. At one time you/dealer could get those plugs and replace them after adjusting. Remember use two feeler gauges at a time to keep from rocker twist to avoid bogus settings.

Big Pontiac guy eh. You go to Classical or PY?

 

The factory states that the INITIAL SETTING (where you begin to tune) is 2 1/2 turns, but that may NOT be the optimum setting cuz carbs, screws and cylinders may vary.

Anytime you find the screws all set exactly the same, the bike has probably not been final-tuned.

 

Agreed.

3% CO is typically 2.5 turns out on the VD series carbs (3% usually giving the best performance at idle).

Easy to test by turning the screws in 1/4 turn increments.