my 2003 Roadstar 1600 runs great.

When the engine is cold and been sitting for a week or two it will make a weird sound in the first minute or so of the engine running and then goes away. Sounds like someone is in there lightly tapping on a hollow metal pipe with a ball peen hammer or something similar to the sound a hot exhaust pipe makes when you first shut the engine off after riding it a long time and everything is heated up.

The bike only does this intermittently and only does it cold start after a week or two of inactivity. Never makes the noise again during the same day regardless of how many times it is re-started or if the motor is cranked multiple days in a row.

This occurs when I do a cold start with the enricher cable pulled out a bit and the bike in neutral resting on the side stand.

A bud who is a long time Roadstar 1600 owner heard it one morning and was asking me what was the source of that noise. His 2001 Midnight 1600 does not do that. Both of us have similar mileage in the low 20Ks and both of us are running Mobil 1 20W50 synthetic with Yamaha OEM filters.

The bike had V&H longshots on there when I bought it and one could not hear this sound above the volume of the pipes. I like quiet bikes and installed stock exhaust not long after purchasing the bike and that is when I first noticed the cold start noise.
I put about 5K miles on it since changing back to stock exhaust and no variation in engine performance etc.

any ideas?

Probably just a light valve tap. You say you have around 20K on it. Have the valves ever been messed with?

Let me assure you at this point that nothing serious is wrong, just trying to help out.

I checked with the local Yamaha dealer before purchasing the bike to make sure the transmission recall was done several years before purchasing it. Maybe the valves were adjusted in that process when it was re-assembled?

The descrition of a ball peen hammer banging on a hollow metal pipe is pretty accurate -- a good bit louder than a light valve tap.

and then it goes away ? ?

The only time I have ever heard anything quite like that description was on both cylinders of a much older bike, and the mechanical timing was crap. Never heard of anything like that in a Roadie. Any chance you are running rich? Post ignition chamber light-off in the pipe maybe?
I'm searching at this point. Sorry.

Couple of thoughts, and they are just that..thoughts, I have the same issue on my 07 Midnight, I'm changing oil, I don't know what is in it now, but it's getting Mobil 1 V-Twin oil, and the other thought is that stupid AIS!! Which is getting round filed tomorrow!!
I noticed mine making that noise, on cold start up, I have pushed in the chock, and my idle drops down to almost dieing, that's when I hear it, but as soon as I'm up to temp, its gone. To me, it sounds like its coming from the over head valve area, front jug only, like a cam ticking or something.

Dos your bike still have AIS?

jd750ace wrote:
Dos your bike still have AIS?

I'll answer for him....yes.

AIS could be the culprit, yes?

My 03 makes so many different noises at different times I've come to ignore them. I can change oil and start getting different noises...then the next day its silent. ??? Go figure. I've come to the point that if its not a loud tap or I can't feel it I just ride it. I'm prob due for valve adjust but untill I can definitely say/feel there's an issue,I'm not touching it. 53k miles and its never stumbled,burped, coughed or let me down ...so until it starts making noises that don't go away or CLEARLY sound like there's an issue..I'm not touching it.

Maybe since yours sits for awhile it takes a few to get the oil flowing?? I don't know since mine never gets that much rest.



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jd750ace wrote:
AIS could be the culprit, yes?

When he was at the house awhile back, and said something about how quiet mine was when I started it up, I suggested he could get rid of it(I think he plans to). Besides being ugly, it just presents a whole list of offending qualities. They do make some noise, whether this is it or not, I couldn't say. For $30 he can find out.
I'd dump the AIS before I started looking deeper.

Another thing he could try, would be a Seafoam treatment of the crankcase oil before his next oil change. If it is a lifter, that might quiet it down some. Couldn't hurt.