How to tell if exhaust is too restrictive?

I currently have a 4 into 1 system on my KZ1000, and have been playing with a baffle setup. I've been using old oil filters just to experiment with how the bike runs and sounds, and this is my latest setup. I used a small oil filter and cut the closed end off of it, and inserted it down into my megaphone. After taking the bike for a spin, it seemed to run fine, but the oil filter had discolored and turned blue. I have used this oil filter trick before, but always used one that was larger and fit in the end of the megaphone, not down inside of it. Is this discoloring telling me the exhaust is too restrictive, or is it discoloring because it is down further into the megaphone? This is probably the stupidest question ever asked on here, but I just wanted to make sure this system isnt going to hurt my engine in the long run.

when you say it turned blue do you mean the metal pieces of the oil filter or are you talking about something else? if it's the metal then it's just getting hot and it alters the crystalline structure of the metal (changes the alignment of the molecules) if it was choking the engine you would either notice a drop in performance and/or blowing out a seal in your exhaust but there's always exceptions. sounds like an interesting set up you should post videos of the before and after filter baffle.

If it was choking off the exhaust flow from being too restrictive, I'd wager it would make the bike run rich and soot up the spark plugs.

Ooooh! Very interesting idea. I might try that to replace my baffle which corroded and fell out last week.

What kind of filter did you use? One from your bike, or an auto filter? Did you remove the filter paper? If not, it would burn up, right?

Did you use any packing material?

How does it sound?

im all in favor of trying different idea's but why would you want to use an oil filter? cost? there are so many aftermarket baffles available that are cheap,on my 900 i have a 4into2 we used a set of baffles design for harley straight pipes and wrapped them with sum fiberglass till we got the sound/performance we wanted and they were very cheap/well made

On my 74 900, i have a 4 into 1 vance and hines header with the baffle it came with. I rode it like that for a while, but it was to quiet. So one day i pulled the whole baffle out completely, took it for a spin around the block. I got back and couldnt hear a thing, so i put the baffle back in but left the wrapping out. It sounded really good but still to quiet for me, so about a week ago i simply cut the baffle in half with my trusty hacksaw and put it back in and now i love it. Its the best of both worlds, not to loud and definatly not to quiet. It gets the attention of the idiots in the air conditioned cages. Hell, i even got a thumbs up from a cop the other day when i was rocking on the throttle. When i get a chance, ill make a small movie of her running and il goose it a few times.