This morning I was looking my bike over while it was running and I happened to put my hand near the exhaust. I noticed that the exhaust pressure coming from the rear cylinder is noticeably less than that of the front cylinder. Is this normal? I would think they would have the same pressure unless something is wrong. My current exhaust set up is stock headers with aftermarket mufflers. The front cylinder's header was extended so that both mufflers would be aligned, which makes me wonder if this added length is causing the increase in pressure.

 

The only way I know of to determine if this is a real problem or a perceived problem is to do a compression test on both cylinders. They should be within 10% of each other.

 

Is it the Nightster? Is the balance tube still used?if so, sounds like the exhaust pulses are picking the route they leave by.
Not an engineer, so I won't venture any opinion on effects to the engine.

 

Thanks for the advise! I've never tested compression on a motorcycle engine, is the same as on a car? Unplug spark plugs, remove one spark plug, replace spark plug with compression tester, and crank?

 

It is a Nightster! I'm not sure what you're talking about when you say balance tube though. I've seem some sportsters that have a horizontal tube connecting both headers, is that it? If it is, then no, I don't have that anymore. I always thought that was just to hold them in place, does it do something else?

 

The visible balance pipe was in earlier years, between the headers and visible. Later, like ours it was moved under the exhaust and incorporated the mounts for the mufflers.
Pics would help.

 

This is a question that has been asked for decades! By all means check your compression, but don't be surprised if your bike is fine. Next time you see a Sporty owner, ask to compare puffs between your two bikes!

 

Need a 12mm adapter to do a compression test. Smallest most testers come with is 14mm.

 

Remove both spark plugs and open throttle wide open while testing each cylinder. Check with an expert but I think this is right. Does both cylinders sound the same?

 

Thanks for all the advise guys! Once I got home I took a closer look at the exhaust when I realized that there was a hole in the side of pipe! No wonder I thought I had heard an exhaust leak. The guy that sold me the motorcycle used rigid mounts without rubber (what a knuckle head!) to hold the pipes to the engine and the vibration finally got the best of them.