I have a 99' Valk that's has been a garage queen. I'm wanting to get back on the road with it so I had it out a few times this past month and it just popped and backfired a bunch when I let off the throttle. The throttle was also very sluggish, especially at low rpm's. So, after a lot of research on this site it seemed like the slow jets and vacuum lines might be the culprit. I wrenched on it this past weekend and thought I'd share what I have found.
Problems:
A) Vacuum lines had three pinholes in them
B) The clamps on the rubber boots conecting the intakes and the carbs were all loose. (3 per carb, 18 total)
C) The gasket material sealing the rubber seals conecting the air box to the carbs were all dry rotted and pealing.
D) The carb bowls had silt in them and the gas was orange in color.
E) My choke was getting stuck open on the right side bank of carbs.
I addressed all of the above issues, put it back together, added fresh gas, Berryman's Chem Tool carb cleaner, and took it for a spin. It now idles smooth, throttle response is great, and it flat out takes off like a fighter jet!
But............
I still have a little popping at let off at 3000 rpm's. Not much but it's there. I have had the exhaust on and off twice with this bike so I ordered some new exhaust gaskets and going to replace the old one's and see what happens.
