| Author | Message | ||
     José_Quiñones |
The latest issue of Cycle World's Power and Performance Harley Davidsons has an article about the race kit for the XB bikes, written by Steve Anderson. The most interesting part of the article actually involves the exhaust design of the old tube frame bikes, compared to the very rigid setup found on the XB. Steve writes as follows:
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| José_Quiñones |
Now, my first thought after reading this was: Would duplicating the rigid mount setup used on the XB on the old tube frame bikes (ie get rid of the rubber isolators and replace with rigid mounts) help the old bikes? Thousands of exhaust studs want to know......... | ||
| Sparky |
I would think it would take a substantially beefier mounting system because the 1203's have more intense shaking forces due to their longer stroke. How much beefier? That's one more question. | ||
| Steve_A |
Obviously, someone could engineer a solid-mounted system that worked on the tube-frame bikes, but it would have to very, very robust, as it is on the XB's. The easiest thing (perhaps -- I haven't studied this) would be to copy the XB system, including the large aluminum brackets. Note that these are the reason an XB muffler wants to have a constant shape along its length, to mate well with these brackets, and why the Screamin' Eagle fetal pig is shaped essentially the same as a stock muffler. Thermal expansion might well be an issue as well; the stock XB design may well allow slight fore/aft slip during a heat/cool cycle to prevent differential expansion loads on header pipes from getting too high. All of this explains why factory mufflers and mounting systems are almost always more durable and reliable than aftermarket. Buell insisted that P&A match stock reliability for the kit muffler, which is one reason why it is not a thing of beauty. | ||
| José_Quiñones |
almost always.... I have seen and personally experienced exhaust system problems with the STOCK system. Once I upgraded to the "Y" mount a lot of my problems went away, but I still broke an exhaust stud last Sept. down at Deals Gap. The exhaust system needs constant attention, I always check the headers and the muffler just to make sure it's not getting loose. I actually did that the morning before the stud broke, everything seemed fine, it broke somewhere between Boone, NC and Deals Gap, but I never heard it because I was wearing my earplugs. Good discussion so far, thanks for dropping in Sparky and Steve, hopefully this won't go off topic. | ||
| Turnagain |
That's where I believe a lot of problems start. You keep cranking down on the nuts and breaking them loose.
have never touched mine & never worry about them either. Years of use holds them in place just fine (grime). 'course a good can helps.  oh yeah, YMMV & obviously does.  | ||
| José_Quiñones |
Steve,
Have you ever SEEN ME DO THAT? I use a torque wrench and tighten to 6-8 lb/ft, just like the service manual says. I would have probably lost at least one muffler on the road if I didn't keep an eye on it over the 32+k miles that I have put on the bike. I have found bolts missing from the rear straps, a broken rear strap (I borrowed one from Andy that day, I still owe him a new one) and loose header nuts before, during and after rides. This is the SECOND broken exhaust stud I have had. I also broke that "L" shaped front header mount that Duck just broke when I had the Buell race header/muffler on the bike. That system was constantly working itself loose, which is why I don't use it anymore. My mileage has varied...... | ||
| Turnagain |
José, man, you're just too easy to pick on. I'd do it more often if I knew what I was talkin' about. 
Nope, 'cranking' was a bad choice, 'tweak' is maybe better. I'm just thinking the metal will fail in time after being 'torqued'. Kind of like being put on a torture rack. | ||
| Dave |
Loc-Tite...load it on. It has work reliably for me with my 99 S3. Some (eg Neil's 'Sparky') seemed to be more vibrator than motorcycle. DAve | ||
| Aaron |
My experience: mount the system right and the nuts stay tight. Lock down the nuts and ignore the root cause of the problem and you're taking a big chance with the studs. I haven't tried going all the way to zero movement, all I know is that I've experienced a HUGE improvement by stiffening up the mounting. The Y mount gets you part way there. | ||
| Hootowl |
I leave everything a little loose and start the bike up for a minute. Lets everything shake in to place where it wants to be. Then I tighten everything down. I have never broken a stud, clamp, strap etc. I even had that POS Supertrapp (original one, not the Buell slip on) and the only place it broke was where the pipe is welded to the can, not at the mounts. I did have an exhaust nut come loose (off) on me. I had the bike less than a week. The dealership didn't have any nuts in stock, but the parts guy said that he had a bucket full of sportster nuts, but he wasn't sure if they would work. I tried not to laugh on my way out. That was the last time one came off. Been just about four years now. Guess I've been lucky. Or some other people have been unlucky. Jeff | ||
| Smadd |
If you keep tightening down the nuts, eventually the gaskets get too crushed and the header flange gets too close (possibly bent in addition to the crushed gaskets) or actually touches the cylinder. Then, you're in trouble. I believe this is true with those "mesh" gaskets. As Aaron said, if it's mounted right, you won't have any trouble or have to pay much attention to the nuts. Mine must be mounted right (by me, through trial and error, or probably by dumb luck)as the nuts rarely need attention. I do look at them every time I ride though... part of my "pre-flight" check. | ||
| Ara |
Aaron, what did you mean by "stiffening up the mounting?" | ||
| Aaron |
Put back on the bracket that the factory eliminated in '99. Notice that in '99, the problems got a whole lot worse. | ||
| José_Quiñones |
I agree that installation procedure is key, I make sure I install it right when I do it myself, ie, loosely install, shake, then I tighten the rear of the muffler, then the front, then go up to the headers alternating between the top, bottom, front and rear studs and then tighten the header/muffler clamp last. I still have problems. I check the system after I get the bike from the dealer, too, which I did the week before the Deals Gap trip when I picked it up from the dealer after they replaced the alternator after it failed on the way to VIR for the Superbike race in August. That quote at the beginning of this topic tells me is that the problems are inherent to the "rubber mounted" exhaust design on the tube frame bikes, even if you mount it right and use the stock muffler. The "rigid" system used on the XB looks to be an improvement, but the XB shakes less, and as Sparky mentioned earlier, I would say that this is a greater contributor to the new exhaust system's improved durability than the mounting system is. On "smoother" bikes this is not an issue: you can install the system not quite right and it won't break, because it doesn't have to withstand the added stress of the vibrating engine. This reminds me of the S3T's right lower fairing, same issue, really (Vibration). Aaron didn't that extra tab help to curb your M2's appetite for exhaust parts? | ||
| Aaron |
Damn, I hate it when I agree with José  You're exactly right though, when you say that it's an inherent design issue. Although not all bikes are troublesome, there are MANY bikes that will consume exhaust parts no matter how perfectly installed the exhaust systems are. That's a fact. I own several Buells. One and only one of them eats exhaust parts, and it matters little how perfectly the system is installed. IMO, addressing the issue on these troublesome bikes requires a design change. Like I said, the Y bracket stiffens up the mounting. It helps. But I solved the problem by retrofitting a 96-98 style collector mounting tab. I can't guarantee that'll fix all troublesome bikes, only that it fixed mine. But the fix is consistent with the message posted above; stiffen it up and it's more reliable. Personally I think it's a bad plan to focus on keeping the nuts on. That's hiding the real issue. Once the problem is solved, the nuts stay on. | ||
| Mikep |
Jose and Aaron, Re: Three Mass, Rigid mounting, Stock XB muffler mount. I used the stock mounting for my 4.1 lb alumimum muffler and one of the things I noticed is that MORE vibration is transmitted through the footpegs. I figure that the response of the system changed because I am now hanging 4 lbs in the same spot that used to carry 14 lbs. Less damping.  mikeyp | ||
| Vindigni714 |
I have a 96'S1,and have broken muffler clamps,(stock)for the seconed time in 18 months. Could anyone point me to a light clamp, that could be dampened at the bolt,like they do with rear fenders(huggers). I have a Borla Carbon muffler. Thanks, Johnny Vindigni,Sr |
