Exhaust dilemma... Inner tubing sizing and baffles

[Anthonyvan]

Sooo.... I have a predicament. I picked up a very abused 79 xs400 from a buddy who has a tendency to cut the exhaust off of evvverryythinggg. So I'm cleaning up the bike and bobbing it out, (and I'm eager to say I'm very excited with the bike. It's such an amazingly operable platform and makes a perfect bike in any category, cafe, bobber, cruiser, I've even seen them be enduros)

Well my question is... I'm running with the cut off exhaust. I want it loud but I want it to sound good. I also want to pay mind to having the correct back pressure and having the carb tuned in accordance with this impromptu exhaust. But the exhaust appears to be made of two tubes, a thicker inner tube and a thinner outer "shield" I'm presuming. So I need to know what size baffles would fit in this inner tube, and if I even have enough length before the bend in the exhaust to baffle it and if any baffle recommendations exist for this particular bike to get a nice solid sound. Orrrrr... Would there be a good custom way to create back pressure without a baffle, ie, a washer at the end of the pipe, washer and bolt welded internally, etc.

Any help is very appreciated!

 

[Scorpio1963]

I don't believe you will find a baffle that will fit the inner tube of the exhaust.You would be better off buying a set of emgo shorties.They will give your bike some back pressure and still be somewhat loud.
You will also have to rejet your carbs to match the open exhaust you have.I also assuming your going to go with pod filters?
Search jetting guide here on the site and that should help get you going in the right direction.
Also Im not totally sure but I think the reasoning for the inner tube inside the pipe is to keep the bike from being cold natured and to keep from burning the chrome off the outer pipe.

 

[Anthonyvan]

Thanks I'll check that exhaust out. I've got pod filters and I plan on rejetting it as soon as I can get it started. If all goes well I'll be able to start it today. It was very neglected but I've given it some love now I will try and upload a picture I'm very excited about it. I'm sure I'll have many more questions along the way

 

[subt3rra]

How did it turn out? I'm about to launch into new pipes and a rejet myself. Did you get it started? What size jets did you use? Thanks!

 

[Anthonyvan]

I haven't, now it appears the carb is going to need some work =( float adjustment maybe, my carb was flooding and not turning over.