Thought noise was cam chain, now not so sure

thanks, got it.
sean part numbers 43028-1010 and 43028-1012 need replacement.

Wow, I thought I was the only one hearing this...

Is the mechanical sync'ing of carbs sufficient or is a vaccuum setup required?

Thanks,

Rob.

550 A4, 65000 Km on the dial.

Hmmm. I think I have the same problem. I thought it was the cam chain, but it makes the most noise at idle.

Saki Jockey wrote:

Wow, I thought I was the only one hearing this...

Is the mechanical sync'ing of carbs sufficient or is a vaccuum setup required?

I did a mech sync and I still get the noise, so I'm going on the theory that it takes a vacuum sync.

UPDATE:

Think we finally have the carbs set up properly. They've been bench synced, not vacuum synced, but, most of the noise is gone.

Before, the lowest it would idle was 1500 or so, and it liked 1800-2000 better. It was hard starting, and would not start when cold without the choke.

Now, it cold starts instantly, on the first turn of the starter, without the choke, even when cold. It still runs like crap until it warms up, but, after it does, it smooths right out. I haven't road tested it yet, hopefully, it'll do well there, too.

It idles great at 1200. It'll idle lower, but, it won't stay smooth, and eventually shuts off at 1000. Also, at 1100 and lower, there's a knocking noise in the crankcase. It's different than the noise it made before, but, it clears up as soon as you idle it up to 1200 or more.

Anyone have any thoughts?

My 550 makes that same knocking noise at very low RPMs, I always assumed it was the sound the bike made when it was about to stall.

That noise would probably be the primary chain. At low idle it is easy to hear it clunk. Usually just bumping up the idle a little makes it go away.
Carb syncing helps too.

mariozappa wrote:

That noise would probably be the primary chain. At low idle it is easy to hear it clunk. Usually just bumping up the idle a little makes it go away.
Carb syncing helps too.

Yeah, that's what I'm thinking. Originally, there was another "chain" noise, as well. I describe it in detail in posts earlier in this thread. We did a mechanical sync on the carbs and all the other noise cleared up, as people suggested it would. Earlier, it made this "clunking" noise at very low rpms, as well as the other "chain" noise. Now that the "chain" noise is cleared up, I can live with this clunking, since all I have to do to get rid of it is to idle the bike up a bit. I just want to be sure that noise isn't indicative of a major problem.

On the large fours, am thinking its the cam chain making noise at low RPM, especially when carbs are not in sync (sounds like its digesting nails in the lower end), due to varying performance among cylinders.

The vacuum sync is believed superior to the ball-park mechanical bench sync, because the vacuum sync measures the true real-world operating conditions, taking into consideration the varying performances among the individual cylinders and carbs, and compensates accordingly.

For example, perfect bench sync settings (if possible) would not necessarily be equivalent to perfect vacuum sync settings.

Even with well-synced carbs, reducing the idle to stall rpm likely results in the death rattle.

At least that's my understanding.

Sounds like the noise I had when the starter clutch came loose from the rotor........It was rattling against the bolts at idle and went away as rpms increased. Replaced the rollers and locktited the new bolts in place and the problem was fixed.....chris3