i have a 99 sportster 1200c. it came to me straight piped....

my mechanic informed me that the EVO engine does not like being straight piped.... he put a a bolt baffle in the pipes but he said that i still have the muffler hangers on the the bike and he suggested putting mufflers on (not OEM mufflers) that it would sound better and perform better... i forgot the brand he suggested... but i have been thinking about it as the weather warms up ... any suggestions out there?

 

Straight, or Drag Pipes, will rob your low and middle end performance due to insufficient back pressure; however, they work well at wide open speed - but who rides like that? With standard header pipes and quality slip-ones, the bike will perform much better and you will significantly reduce the chance of burned valves.

 

Your mechanic is quite right - straight pipes are essentially drag pipes. The main reason for installing mufflers, other than reducing noise, is to improve torque through the normal riding rev range. Ask him again what mufflers he suggests and we can comment. Firms like Supertrapp produce mufflers similar in shape to stock ones, but with adjustable baffles, which I've used and been very happy with.

 

these are the ones he suggested. Cycle shack Slash Cut Slip-on mufflers MXL-134SSA
https://www.denniskirk.com/cycle-sha...rd/H252047.sku

however i notice these are rated as loud.... would like something less loud and more rumbley....

 

I wouldn't exactly call them very loud. These are the exact slip-on's I have. Love em! They are louder that some, but not in your face. I removed the baffles from mine and installed the thunder torque inserts so now they are loud, but such a beautiful rumble!

I notice from the website they are no longer available.

Here is what they sound like with the baffles installed:

 

You could look at putting Thunder torque inserts in your straight pipes, talk to DK for those.
The Cycle Shack are a popular cost effective option that most people on the forum here seem happy with.
I went with the old style SEII's and love them (nice deep rumble but not stupid loud) but they are getting harder to get, do not go with the new style SE street performance as they are very close to stock because they are legal in all states.

 

If it's running good with straight pipes, no backfiring or farting, the carb's been rejeted, maybe other tweaks. With more restrictive mufflers, you'll be running rich, but the factory setting was so lean you might get away with just adjusting the mixture screw; I did that on my 1200 when I swapped the drag pipes it had with mufflers, runs fine - better than it did with the drag pipes, under 4500 rpm anyway.