2012 Magnum Exhaust Design -- Grrrr! By ellpee (Read 968 times)

[ellpee]

Am currently very annoyed with the dual exhausts on my Magnum. The header is of course bolted to the engine, while the mufflers are bolted to the rear frame. Consequently, the pipe joining the two has to be able to flex, and Ice Bear's solution is a hybrid of steel pipe that inserts into the muffler and woven steel mesh "pipe" that inserts into the header. The solid steel pipe is supposed to be held in position by a really big clamp on the inlet end of the muffler, but it has proven impossible to tighten that clamp enough to actually keep it in place. Because of that, the entire intermediate pipe is able to move forward and backward, and the exhaust seal is virtually non-existent -- the outside of the pipe and muffler continuously show soot deposits. Worse, the leaky exhaust appears to have some negative effect on how the engine runs, as back pressure fluctuates with the movements of the intermediate pipe.

My most current attempt at a fix involves a section of flexible metal "pipe" that I bought at a plumbing supply store. I already see that exhaust is still escaping at the inlet (engine) end of that pipe, so I plan to apply some high-temperature Permatex to that connection and see if it provides a better (and more lasting) seal.

Anyhow, I write this (1) for the general eddjicashun of the trike public and (2) to see if anyone else has had similar problems and found a better fix. The local scooter shop gave me a pitch about replacing the header pipe with a single exhaust design, saying all the curves and bends in the header pipe serve no purpose and a single, straight outlet would be better. I'm leery of that, though, because I'm sure it would considerably change the back pressure specs and therefore might require additional "upstream" adjustments to valves, carburetor, etc.

[cyborg]

Maybe a couple of flanges welded on there will cure the problem,,,,perhaps a redesign is in order ,,go down to one pipe,,,less parts less problems less weight,,,less headache,,,post some pics if you get a chance

[ellpee]

Well, the "one pipe" solution might cause me grief with valves and carb due to different exhaust pressure, que no? I'd be fine with it except for that. Anyhow, trying to attach some pictures; if I succeed, will write more to explain.

i982.photobucket.com/albums/ae308/paholskila/DSCN0742_zpszvbqnnyy.jpg

i982.photobucket.com/albums/ae308/paholskila/DSCN0740_zpshdqtvjps.jpg

i982.photobucket.com/albums/ae308/paholskila/DSCN0741%20-%20Copy_zpsbonnnvnw.jpg

Assuming these links work, the first is the factory connecting pipe, in one case intact, in the other case the steel mesh flex part has separated from the solid steel part. In any event, the design intent was for the solid steel pipe to fit into the muffler and the mesh part to fit into the header pipe. They do, but are by no means sealed.

The other two pix are the current state of my dual exhausts: a piece of plumber-grade flex pipe, with high temperature silicone "gasket maker" providing a seal at both ends. No idea yet how that's going to hold up, although I ran it for a few minutes this morning and it didn't immediately blow out, so I'm hopeful it will stand up to whatever exhaust pressures this li'l ol' engine generates when it's climbing a hill or hauling butt down the highway.

You can probably see on the latter two pix the big clamp that is supposed to hold the pipe in place at the muffler end. NOT!!! You can crank on that until the cows come home, it does not compress the muffler inlet enough to grab the pipe and hold it in the proper position.

LATER: took it out for a two-hour, maybe 20 mile, many-enroute-stops run. Exhaust noise enroute was moderate, back at home, one side seems to have held 100%, the other is loose but it appears more of the silicone goop might fix it. Will post more.

[cyborg]

I think you're on to the fix,,,I like the flex pipe way better than the mesh setup,,,cut another slot in the muffler collar,,so it will be four petals instead of 2 half pipe sections,,,I think it will " clamp" better and the other end four "set " sheet metal screws will do the trick,,with a generous add of the hi temp sealer,,,then maybe motorcycle pipe wrap to top it off and you got it licked

[ellpee]

My mufflers already have four "petals," and I discovered in the course of all this that the inlet on the muffler also has a tubular gasket-like insert. On the right side I ditched the big clamp and put a couple screws on one muffler per your suggestion; left the other one (left side) as is until see how it works out on the right side.

I also noticed that there's a lot more pressure on the left side than on the right, as the left muffler is the first one in the sequence off the header pipe. The header then loops back on itself to connect to the right muffler, so less pressure on that side.

[jopo1668]

I have same system on my 2012 but it kept breaking mounting brackets so welded brackets back together a little stronger though but between the two brackets muffler an frame brackets I put about 1/2 in of rubber tighten well it has not cracked or moved in over 1000 mi . rubber used was a robber stair tread from homdepot

[ellpee]

As it happens, I talked to a local muffler specialty shop a couple days ago. Although he doesn't have the appropriate size of pipe -- it's only about 1" -- he agreed that the design is stupid, all kinds of 90-degree turns, needless routing of exhaust back and forth from right to left, etc. If I can find the right pipe somewhere, he says he can rework it for much more direct exhaust flow to the two mufflers, or, if I prefer, eliminate one muffler altogether and just go with one or the other (right would be a more direct routing from the exhaust port). He didn't think it would affect back pressure appreciably, but if anyone here thinks otherwise, please sound off.

BTW, there is a sort of "canister" thing in the exhaust path, first in line off the cylinder before either of the mufflers, and neither I nor the exhaust guy had any idea what it's for. On a car, it's more or less where the catalytic converter would be, but that's surely not the case on a Chinese scooter ... ?? Anybody here know? Could it be eliminated, or is it something important?

[crwford]

My 2015 hasn't one on it but the stupid flex pipe fell off I found my rv generator uses the same size pipe cut to 8 inch Pisces and welded both sides slid them into mufflers works great.

[ellpee]

The Magnum's in hibernation for the winter up in Ruidoso, but this battle will resume next spring.

[cyborg]

i think the rv parts fix sounded like a viable solution,,,,bummer you have to put it away for the season,,,i'd be draggin it to tuscon if it was me,,,,gotta have my rides at my fingertips at all times or i get weirder than i normally am

[crwford]

Here in east TN weather in winter is you can ride most of the time only get really ruff for about 3 to 4 weeks. Will still be riding unless it's a raining season time will tell?

[cyborg]

hey how are you healing up from your lay down?

[ellpee]

Not bad, good bill of health from Dr this past Monday but still looking at wearing the back brace for another month or so. Ribs were the most painful part, and they are evidently healing well, can do a lot of things now that hurt like the devil the first few days. Bummer when you feel a sneeze coming on and know how much it's gonna hurt!

I may well bring the Magnum back to Tucson eventually, either to ride or to sell -- have to see if the Boss will tolerate me riding again, even on a trike. Bad part about the crash is not remembering anything about the circumstances. If I knew it was a patch of loose gravel I could be more careful about that in future; ditto if it was wet pavement, etc., etc. But if I had some sort of vertigo episode any riding at all would be a big gamble, and I just don't know what caused me to wipe out. Makes getting back in the saddle somewhat scary.

[crwford]

here is my fix so far so good time will tell

[ellpee]

Interesting, no flex at all in that connection. Since the engine and the mufflers are attached to two entirely different frame structures, will be interested to see how that works out.