[Bayonet]

I have a 2000 sportster with drag pipes. It made this same noise with the factory pipes though. I ended up figuring out that it is coming from the rear cyl sucking back in through the exhaust pipe. The bike runs like a raped ape so I don't think its a valve issue but I could be wrong. You can easily feel it if you put your hand in front of the pipe. Could this be from the big open pipes and I just need to baffle them? I'm thinking it's more prominent from the rear cyl because of the shorter pipe. Am I off or is this most likely the issue? I appreciate any advise.

 

[Bayonet]

Here is a vid of the sound im talking about. Hopefully somneone can point me in the right direction.

 

[Bayonet]

Anyone or is that normal?

 

[Hillsidecycleco]

Wish I was better at diagnosing noises from video clips.
I'm not good at it.
Scott

 

[Kainam]

Agree.

Are you able to determine where the sucking is coming from?

Is it the exhaust outlet, or at the head?


If its at the outlet, that's normal for exhaust pipes with little baffling.

Look up "Washer Trick" to help correct reversion timing.

 

[THE ROAD]

Sounds like un-baffled 2" straights . You need 1&3/4" drags !
Also loosely hang a rag over each exhaust . See if one or both pipes try to suck the rag into the pipe !

 

[02Deuces]

sounds normal to me

 

[JPR]

My 1968 sportster with drag pipes and Mikuni carb sounded like that.

If you are happy with the performance, leave well enough alone. You cant get an FI bike to sound like that.

If you want more performance, get a 2 into one with little or no baffle.

Just my opinion. There may be better configurations.

 

[Hillsidecycleco]

A set of Cycle Shack tapered "M" pipes would bring a pile-o-power over the drag pipe set-up.
Scott

 

[midnightrun7]

I just replaced a header that had a crack midway through my exhaust. Drove from NY to CO and Back. I had so much carbon on my Valves and Pistons they were hitting each-other. Major valve train noise. Not sure if that was the cause but your bike will be out of tune. I'm throwing new baffles on the slip-ons as well. Just food for thought and my 2 cents. Good Luck!

 

[Bayonet]

Great piece of mind thanks. It is 2 1/4 in drags. I know it isnt a great setup for power but when you drop off the throttle it sounds beautiful and brings a smile to me every time. The sucking is comming from the end of the exhaustand that immediatly made me think valve issue. Im still pretty new to the wrenching on motorcycles and pulling the heads seemed terrifying. I have a set of BCT baffles and when I pull the exhaust to paint them ill slide them in. I appreciate the help guys.

 

[Bayonet]

After the thunder monster baffles the noise is almost completely gone and you can barely feel any suction between exhaust pulses. I lost some of the sound engine braking but picked up a ton of midrange power. I'm fairly certain I could have made the baffles for around 10 bucks from the looks of it but I'm happy with the end result. Thanks guys.