Project: Resurrections / 1999 Standard

For those of you who might remember me, I rode with the VRCC /Texas Chapter for a while until work took me out of the country back in 2012. I am back in the states, retired and settled in Daphne, Alabama. As I am moving on to the more important things in life, I am trying to get my Valk back into running condition. I am having a few issues and, frankly, although I have had some success in searching for leads on the tech board, I'm not sure of a root cause or what might be the best starting point. For those who read on, I sorry about the length of this post but I will try to provide as much data as I can.

The bike is a 1999 Standard with a 6 degree trigger wheel and 6x6 exhaust Other than that the engine has remained stock. For the past 8 years the bike has been in environmentally controlled storage. The fuel tank was kept full and the gas was dosed with Star-tron and Stabil. The battery was kept charged. About once or twice a year I would be back in the states, when I would drain out the old fuel and replace with fresh. About once a 12 to 18 months I would change the oil. Typically, I would get the bike out of the warehouse for short rides (any where 20 to 100 miles). If I could not ride, I would at least start her up and warm her up to operating temps (both oil and water). At times it was a bit slow to start but once started seem to run well. During the last 18 months of my assignment, I was unable to get back to the states and the bike sat idle a bit too long.

On my final return, I had issues starting the bike and once it was fired up it would not idle at all. I could get the bike up to a cruising speed and it would eventually run smoothly but didn't seem to be hitting on all cylinders (seemed sluggish). When I give it the throttle, I would get a lot of missing, popping (exhaust side) and backfiring (carb side) for 15 to 20 seconds then she would light up and she would accelerate like she should. In an effort to get her to idle, I adjusted the setting but she is only hitting on 2 cylinders hitting (checked the temps of the exhaust piped). When I try to throttle up from idle, again the popping and backfiring, but never smoothing out or hitting on all 6 cylinders. At this point the bike is pretty much un-rideable.

Since my return, I have:
1) Replaced the battery
2) Replaced the fuel (Shell V-Power with Sea Foam added)
3) Changed Oil and filter(Rotella 20W50)
4) Cleaned and gapped plugs (0.035")
5) Checked for vacuum leaks - While looking for leaks, I noticed that all 6 of the outside bolts on the down-comer between the carbs and the cylinder heads were missing. As all 6 were missing from the same location, I wasn't sure if these was typical or not. I replaced them but nothing improved.

I figure it is either the carbs, ECU or a timing issues or a combination, but before wondering off on my own (and possibly do additional damage) I would like to get some input from people who appreciate my situation.

Any advice or assistance would be greatly appreciated.

Sambeaux

Just a quick update:
Spent the day looking over a few things -

I swapped out the ECU for a unit in my spare parts bin. No change.

Not really sure how to check the timing but based on the timing marks (right, center and left) everything seems to line up together.

Starting to think its a carb problem but....

Read an old post concerning a similar sounding problem suggesting it might be the firing sensor (at the trigger wheel). Any suggestions on how that might be checked?

Another post found low voltage to the plugs but did not state how they tested for that. Give the spec @ 100 volts min. with a test results in the 70's - 80's.

Other possible causes would be appreciated.

S