Arrow Exhaust Leak?

[antrides]

I recently bought a 2012 Scrambler 900 from a friend that he had installed an Arrow single exhaust on. I've noticed that the "engine" feels a bit rattly. Mainly around 4k rpm, but not exclusivevely. I just replaced the oil, thinking maybe it had been a while, but when I got back after riding around a bit afterward, I noticed a little bit of smoke coming from the midpoint of the exhaust (video here). I'm not really sure if maybe there's an exhaust leak? Maybe the leak is decreasing back pressure and causing the rattling feeling? Any help would be rad.

 

[atomsplitter]

That vapor coming off the wrap could be just water being cooked out from the last wash given the bike. When you say "rattly" to what are you referring i,e., noise at idle or vibration while riding? Is it something banging around, or does the bike feel like it's coming apart? Without specifics it's hard to provide useful feedback.

If you have an exhaust leak, you can pull one of the spark plugs and look at the electrode color to see if it's running lean. The normal color should be a very light chocolate brown, too lean and it will be more ashy white, too rich (not likely with an exhaust leak) and it will be black.

 

[antrides]

That vapor coming off the wrap could be just water being cooked out from the last wash given the bike. When you say "rattly" to what are you referring i,e., noise at idle or vibration while riding? Is it something banging around, or does the bike feel like it's coming apart? Without specifics it's hard to provide useful feedback.

If you have an exhaust leak, you can pull one of the spark plugs and look at the electrode color to see if it's running lean. The normal color should be a very light chocolate brown, too lean and it will be more ashy white, too rich (not likely with an exhaust leak) and it will be black.

Good call on the plugs, I’ll definitely check those out!

As for the “rattling,” it’s up near the front end, sounds like it’s down near the engine and really just kinda sounds like something may be a little dry.

I can’t feel it in the bike, doesn’t shake or anything and doesn’t feel particularly dangerous to be honest, just doesn’t sound like it probably should. It’s not a thump or a loud knock on any defined interval.

If it were more rhythmic I would think it was something gnarly, even like a loose cam chain or something, but it’s a little too random (even though constant) than I would think any moving part would be.

Sorry, wish I knew more so I could better describe it!

 

[atomsplitter]

Not sure if your headstock bearings are sealed or loose. But the description could apply to headstock bearings need adjustment. If you can elevate the front end check if there's any freeplay at the triple tree. Grab the lower forks and see if there's any front to back movement.

 

[antrides]

Not sure if your headstock bearings are sealed or loose. But the description could apply to headstock bearings need adjustment. If you can elevate the front end check if there's any freeplay at the triple tree. Grab the lower forks and see if there's any front to back movement.

Definitely going to check that, it didn't seem the way on the ground. Luckily I worked in a bicycle shop in college, so some of this stuff is very similar. Looks pretty good to me, while looking at the exhaust I did notice that the exhaust headers weren't very tight. I'm gonna reapply some wrap, replace the gaskets, and get that all snug as well.

The fact that it doesn't seem to happen at idle gives me hope that it's nothing super gnarly.

 

[sikatri]

Definitely going to check that, it didn't seem the way on the ground. Luckily I worked in a bicycle shop in college, so some of this stuff is very similar. Looks pretty good to me, while looking at the exhaust I did notice that the exhaust headers weren't very tight. I'm gonna reapply some wrap, replace the gaskets, and get that all snug as well.

The fact that it doesn't seem to happen at idle gives me hope that it's nothing super gnarly.

Exhaust being loose could definitely be an issue.