xs400 exhaust air intake mods

[Bartolucci]

I have an 82 Heritage Special twin that I recently inherited. One mod. I made was to remove both of the plastic air filter boxes connecting the air filters directly to the rear carb boots. I was hoping this would not result in any carb adjustments and, so far, so good.

I'm wondering about options for exhaust mods. I'd like to get a little more noise and flow. I've read that a twin on open tubes isn't too bad - I am sensitive to how irritating open-piped harleys can be. But I would like to be louder (removing the air boxes did some) and improve the flow. I don't want to spend much money, such as on headers. Any ideas or first hand experiences?

Thanks

[jjwaller]

I've looked in a couple of places and looks like a MAC is it.
Dennis Kirk and Old Bike Barn.
Might look around a bit further.
As far as the air filter, you will need to re-jet. I know it's not cool, but
stock is best. Especially for re-sale value.

[Bartolucci]

Re xs400 exhaust air intake mods

Reality sets in and I realize that messing with the exhaust would likely be more trouble than it's worth. I don't want to mess with a carb re-jetting experiment.

However, the bike runs stronger since I've opened up the air filters. Perhaps I should check the plugs after a while to make sure it's not running too lean? http://www.xs11.com/forum/images/icons/icon5.gif

[fredintoon]

The ol' pointy bar treatment.

I have an 82 Heritage Special twin that I recently inherited. - - - I'm wondering about options for exhaust mods. - - - I would like to be louder (removing the air boxes did some) and improve the flow. I don't want to spend much money, such as on headers. Any ideas or first hand experiences?
Thanks

Hi Bart,
What I did to all 3 of our XS650s was to take a pointed steel bar, shove it into each of the mufflers right on the bike and pound on the end of the bar with a BFH until the baffle tube inner end caps popped off.
Did my '78 Special first, it sounded a bit raucous. Then my son's '80 Special because he insisted, that sounded a little less raucus. Finally did my '84 Heritage and that sounded just right. I suspect that Yamaha kept adding baffles over the years so that the newer the bike the less the effect of punching the muffler endcaps open. As your XS400 is an '82 it should sound not too bad after treatment with 250ccs less engine capacity making the noise.
Real easy to do and costs nothing. The only drawback is that it's a one way deal. "No backsies"

[Bartolucci]

Bustin' Baffles

Fred,

I know my mileage may vary, but did you have to rejet any of the bikes after this mod?

Second, I've never messed with jets, but from what I recall, the plugs tell the story as to whether the bike is running too lean or rich, correct?

TIA

[jjwaller]

Just about all bikes from those years, and earlier, need to go richer.
EPA stuff started in the late 70's and all the mfg's started shipping
most bikes jetted a bit on the lean side. With exhaust and intake mods,
(or even stock) it usually helps to go up a size or 2.(or more)

[fredintoon]

Fred,
I know my mileage may vary, but did you have to rejet any of the bikes after this mod?
Second, I've never messed with jets, but from what I recall, the plugs tell the story as to whether the bike is running too lean or rich, correct?
TIA

Hi Bart,
none of our XS650s were re-jetted and the plugs stayed the light tan they are supposed to be.
BUT
our Canadian model carbs are not as leaned out as the US models so heed JJ's warning about over-lean carb jetting on your bike.

[Bartolucci]

Thanks Fred!

[res1uqtp]

Don't know if this helps or not but I cut off the original exhaust where the header meets the muffler and slipped on a pair of pre 05' Harley Sportster mufflers. One is mounted upside down but you have to study it pretty close to catch the writing.

I didn't have to rejet but the airbox is still stock. I'd imagine your in for a rejet with that mod.



Hope it helps ....

[Bartolucci]

Thanks res1uqtp

I saw your bike on the pics page and am glad you responded. How is the sound of the Harley mufflers?

Your little XS is in beautiful condition. Mine is a little more ratted out cosmetically, but only has 12k original miles. Got the title from the owner today - they bought it in 1989 and only put 4k miles on it in 20 years.

I check the plugs today. They look rich. So I don't know if opening up the air filters did much in that regard, but it does pull harder. I'm toying with the idea of knocking out the baffles (previous post).

Over 50 degrees in New York today and got a little riding in (jeans and a t-shirt).

TAB

[res1uqtp]

I saw your bike on the pics page and am glad you responded. How is the sound of the Harley mufflers?

Your little XS is in beautiful condition. Mine is a little more ratted out cosmetically, but only has 12k original miles. Got the title from the owner today - they bought it in 1989 and only put 4k miles on it in 20 years.

I check the plugs today. They look rich. So I don't know if opening up the air filters did much in that regard, but it does pull harder. I'm toying with the idea of knocking out the baffles (previous post).

Over 50 degrees in New York today and got a little riding in (jeans and a t-shirt).

TAB

Thank you. It was pretty ratty when I first got it and I told my wife I was going to "just clean this one up and ride". I guess our definitions of "just clean" were a little different

They sound really really good. I just balanced the carbs and then used a colortune to fine tune mixture at idle and it kicks right up first time every time. Incidentally, that colortune was the best tool I ever bought.

Feel free to pm me if you have any questions. I'm no super mechanic by any means but I know my way around this model pretty well.