I agree w/ pulling the plug wires, one at a time. If the knock goes away with one certian plug wire pulled, it may very well be the rod or piston pin on that cyl. I have had pins that were bad on engines, but when it warms up, the knock would tend to go away some, by way of the heat on the piston. If the knock doesn't go away by pulling plug wires, I'd be looking for whatever goes around in circles. Possibly a bolt tapping the case, stator, clutch area, ... You can try a thicker oil, like strait 50w. If the noise tones down some, I'd think there may be some slack in a bearing. Last, piston slap.

inogivearats wrote:
RUNNING straight 50 is no different than 20/50 when the engine oil is at operating temp and the MAX motors do make some funny noises I would ride it a while and see how it sounds

The bike does have high miles, 40,000.
I tried to isolate the noise by removing one spark plug wire at a time. In each case the RPM's dropped and the noise did not change.
I don't notice any difference whether the bike is upright or on the stand. The plugs have about 3,000 miles on them. I attempted to sync the carbs with a manometer that was itended to be used on 2-cylinder bikes. The carbs are likely out of sync. I haven't looked at the carbs. The noise sounds very much like a rod knock. This is my second 1985 V-Max, it is not a "normal" noise.
I appreciate all of the feedback.
Bob

IMFASTTOO wrote:
quote]RUNNING straight 50 is no different than 20/50 when the engine oil is at operating temp and the MAX motors do make some funny noises I would ride it a while and see how it sounds[/quote]

That is correct, 'at op temp'. Now, what is the '20' for? Yep, just run it out and see what happens. Guess I should of pm'd.

Bob, Maybe I'm wrong but I'm under the assumption you've had this bike for some time, then noticed a new knock. I'm also 'guessing' you're using std wgt oil for the bike, 10-40. Was just throwing out some ideas.

It's hard to tell how the bike had been run in the past. Sounds like you ruled out a pin and rod. I take it the bore was in specs. When you drop your oil (you prob know this), use a clean, lite colored pan. I'd look at the oil in direct sunlight, looking for flakes. You can use a strong mag to run through the oil. Since you've just overhauled the eng, you'll get some and some coloration off the bearings, but hopefully not many/ bigger chunks. You can ck your filter, too. Have you pulled your clutch in and out? My Gen 1 made a bit of extra noise with the clutch out, engaged, turning the shaft. Another thing to try, find another Max nearby, as to compare the engines running. Hope it helps.