'84 VF500 Valve Adjustment & Carb Sync

Hey guys, I've got an '84 VF500 that I'm trying to get running smoothly before the summer. It's my first bike, has about 16k on it, and no idea what kind of maintenance the previous owner did. Since I obtained the bike (at age 20, five years ago) I've put less than 100 miles it :crushed: Long story short this bike has been an ongoing battle against my inexperience, age of the bike, sitting for long periods of time, funky stuff the previous owner did, and time & money. That said I've learned a ton and have been completing more and more difficult tasks as time goes on. I'm hoping I can finally break the stalemate, get out of the garage and put a few thousand miles on this sucker before the season is out.

Last week I had it running pretty well, idling around 1300 and no longer hanging post revving after replacing the carb boots due to suspected vacuum leak. However, before declaring victory I wanted to sync the carbs. I had bench synced the carbs last time I cleaned them. Hooked up an emgo gauge and the readings were 10in vacuum on #1 and 5in on #2, #3, #4 (4 is the reference carb for this one), which is pretty funky. Thoughts?

I didn't realize I'd need such a special tool to adjust the carbs before I checked them, so I ordered that and while it was on the way decided to do a valve adjustment. This went pretty well (I think) other than a couple minor hiccups. After getting the radiator off (2.5 hrs :tranquillity, I went to take off the timing hole cap and naturally it was stuck. Really stuck. Penetrating oil, clamp on a large flathead screwdriver, nothing. In retrospect I should've just used a hammer and tapped on one side of the slot or used a quarter in the clamp, hindsight 20/20. The timing hole cap is no longer with us, but it's off. I'm looking for a replacement but they're impossible to find. If y'all know where to snag one please let me know.

Finding TDC-C was pretty confusing, so I'm hoping I got this right. My understanding is that in a 4 stroke cycle the flywheel turns around twice, 720 degrees. There is a "TR" mark corresponding to 0=720 and 360 degrees, TDC-E and TDC-C respectively. The cycle is something like:

0 -> 180 (Intake Stroke): Begin with piston at top of cylinder and both valves closed @ 0 (TDC-E). Piston moves down while intake valve opens. Fuel/air mixture flows in. End @ 180 with piston at bottom of cylinder and both valves closed.
180 -> 360 (Compression Stroke): Piston pushes up through cylinder to compress fuel/air mixture, valves closed. End @ 360 (TDC-C) with piston at top of cylinder and both valves closed.
360 -> 540 (Power Stroke): Spark ignites fuel/air mixture. Piston moves down through cylinder, valves closed. End @ 540 with piston at bottom of cylinder.
540 -> 720 (Exhaust Stroke): Exhaust valve opens as piston pushes up through cylinder as exhaust flows out. End @ 720=0 (TDC-E) with piston at top of cylinder and both valves closed.

I checked the clearances at what I'm calling 360 degrees, the end of the compression stroke. If I did things right, then the valves were incredibly tight. I couldn't fit a .002 feeler into some of them. This was concerning but doesn't seem impossible. I went ahead and adjusted them to .004 intake and .005 exhaust as per FSM.

In the process of putting everything back together I over tightened one of the valve cover bolts and snapped it :worked_till_5am: Learning things the hard way here, that was at hour 7 with no torque wrench *doh*. I ordered a new one and will try to extract the snapped bolt.

Any comments or suggestions as I try and get the lids back on these two cans of worms would be much appreciated. Thanks!

 

Reference to exact timing marks is critical when setting cam timing, but NOT so important when checking and adjusting valves ! In fact you didn't need to remove any access covers either as valves can be checked and set at ANY PLACE where the cam is NOT depressing the valve, any point where the cam lobe is pointing generally away from the valve top. tURN THE ENGINE OVER WITH THE PLUGS OUT BY ROTATING THE REAR WHEEL or a momentary push on the starter button. Don't waste your time trying to get closer than the tolerance allowance of + or - .001" from the nominal spec. A bit loose is preferable too tight, and you can always measure 2 valves at any crank position.

To repeat: those timing marks caN BE CONFUSING and are unnecessary for setting valves, despite what any manual suggests.

Breaking small bolts can be avoided by using smaller tools, such as 1/4"-drive sockets.

 

You should be able to back out the remnants of the valve cover bolt with a dental pick or similar tool. Haven't come across one yet that did not just back out with a little help.

 

No go with the dental pick. The entire length of the bolt is in there with quite a bit of torque from when it snapped. I'm thinking of trying a bolt extractor or hammer & point. Any other ideas?

Edit: Time for a beer.