I mounted some Harley pipes today...

[Bonz]

Thanks Mharrington...

I've heard the older engines can clog the cat's becasuse they weren't designed to digest what these old engines put out the exhaust. I've wondered about that, as cars ran with cat's for years and were carbureted. I would think that old engines burning oil might clog the cat's, but if the engine is in good tune and of good health, the cat's shouldn't be a problem. Any thoughts?

With no seat of the pants difference in performance, did you get any difference in fuel mileage up or down?

With my bike, the rear 7"-9" is rusted out on each muffler. After all the great input from the forum and otherwise, I'm going to cut each side off just behind the muffler mount bracket (keeping the crossover) and graft on the back end of a sportster muffler.

CaptonZap did this on one of his 80G's, and other than a tasteful clamp/ring around each junction, the pipes look stock and was able to end them before the axle, along with not changing ground clearance.

[mharrington]

I read about the cats becoming clogged eventually. That may happen but I only ran them for about a month. My mileage remained the same. Due to the stress I placed on them to align them "correctly" one cracked completely at its weld. I got both mufflers- in fantastic condition for under $30 so it was not a waste of money. I really had to muscle them into the position I liked and then tighten clamps and brackets. Too much stressing. In the future If I try again I will not simply bolt sportster mufflers to the XS pipes but install a pipe extension between mufflers and pipe to position the mufflers and get them further rear ward.




Sportster mufflers are an easier adaptation on my XS650.

[Bonz]

The pipes do look pretty good, too bad they wouldn't last for you.

What was/is gas mileage on your 1100?

[mharrington]

My 1100 is giving me about 37 mpg. I weigh 240lbs and the bike runs great. Some get better and some get about the same.

[Bonz]

I am right at 37 mpg as well. Seems to be a fairly common range to be in.

[mharrington]

I used to have a 78 XS750E triple. I got about 38mpg on it. My XS650 twin gets about 45.

[fredintoon]

Here are some more close up photos of the bracket I made... It's a pretty simple setup. - - -

Hi Kris,
and sturdy, too. OTOH those chrome Zeppelins are sinking at the stern.
Let me suggest you slightly shorten the bracket's bolt centers to lift the mufflers up to horizontal
and either modify the bracket or add an auxiliary bracket so that it bolts to the stock muffler mount AND the rear footpeg bolt
so the bracket can't hinge down to let the muffler sag down again.

[UtahXS]

They do sag a bit.... I noticed it too.
BUT, they are as far up as they can go. They are already wedged up against the footpeg mounts, and are slightly putting torque on the headers.
I put them up as far as I dared to go with them...
They are pretty big mufflers.

[fredintoon]

They do sag a bit.... I noticed it too.
BUT, they are as far up as they can go. They are already wedged up against the footpeg mounts, and are slightly putting torque on the headers.
I put them up as far as I dared to go with them...
They are pretty big mufflers.

Hi Kris,
Yeah, I got a set of H-D Zeppelins at the same swapmeet as the 1960s Triumph pair that I fitted to my XS11SG after I got both sets home and worked out how effin' huge the H-D muffs were.
Here's the leftside ex-Triumph muffler in place:-



The Triumph mufflers mounted right up to the stock mounts but not before I got medieval on them with a ball-pein hammer to make the grooves that let them snuggle up to the brackets.
The old engineering phrase "If it don't fit, use a bigger hammer." may work on your ex-H-D mufflers too. Anyway, you can't see the dents in my mufflers unless you pull them off first.