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Exhaust/crossover crapola


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Guest Brian Robson
Posted

Basically my exhaust system is falling apart, being replaced throughout by a series of welds; both of the headers, one tailpipe and now the crossover has given up the ghost, with both tail extensions cracking again, the "teabag" inside coming off its spot welds and leaving 6 pin holes. :(:(

A big thanks to Helicopter Jim for selling me his old stock crossover, :thumbsup::thumbsup: and managing to get it to me for tomorrow, hence saving my job, allowing to keep paying for the bike, and so the point of this, is what I plan to do with the old crossover.

I have asked a welder that I use to cut out the entire crossover section so that from the outside it appears as if it looks the same and where the square section has been removed welding some flat SS plate. This would leave basically two separate pipes, and we will put two braces connecting the pipes near the sump and in front of the wheel.

I know that this has been discussed before, but are there any drawbacks to having 2 pipes without a crossover. Obviously the sound will change, but will it have adverse effects upon either rideability or performance?

Because this is a basically a spare "crossover", I will try it anyway and try to put a sound file on the site. It will be completed in a couple of days. :bike::bike:

Posted

For your information! Mamacita will have the crossover at Dakota's restaurant at about 0930 pacific time. I hope that all wil be OK and if you ever want to eat at Dakota's I will get you a great deal ( she owns it)!!

Let me know if all works out and we should meet at Dakota's some day!

Posted

Great. Now I have to give directions to a place I go every week ( and more).

 

Dakota's restaurant is close to downtown Chilliwack. Behinnd the Dairy Queen as I say! I wish I could reccomend it to every one but that would be crossing the lines of business. (meaning come all!!)

Ciao everybody!

Posted
but are there any drawbacks to having 2 pipes without a crossover

I think you loose power. But you have the pipe in front of the alternator, so the engine has something.

Posted

Brian,

 

No science but I always felt Guzzis needed crossover. Tried separate pipes on my Tonti - lost power, gained nothing - but could have been that specific set up. Couldn't you join the two pipes where they meet? I think Raceco did it that way?

 

I think stainless cracks if you introduce stress into the system when mountings don't line up perfect. My old Tonti used to regularly crack at the H piece until I made up some rubber mounts for the back fixing. Not sure that bracing/ more rigid mounting would help...

 

KB :sun:

Posted
I know that this has been discussed before, but are there any drawbacks to having 2 pipes without a crossover. Obviously the sound will change, but will it have adverse effects upon either rideability or performance?

 

The crossover exists to balance the exhaust flow between the two mufflers. By isolating the exhausts the way you intend, you'll double your backpressure [same flow thru 1/2 the muffler volume per cylinder] and lose power. BUT, w/ the increased back pressure your torque curve will shift and you may fill in the "hole" at 4500rpm...

 

Best of luck!

 

PS: there's a specific set of instrux out there on the web on "how to bolt up your new exhaust to your Hog." The key being you only bolt up your pipes loosely until you fasten them at the head and work your way back to the muffler. This supposedly keeps them from cracking; did you follow the same procedure when mounting your exhaust? Just wondering...

Posted
The key being you only bolt up your pipes loosely until you fasten them at the head and work your way back to the muffler. This supposedly keeps them from cracking

 

Mine started to crack at 3000 miles (6 months old) , about a month after I fitted the techno rack so had undone the muffler hanger bolt. The muffler moved during fitment but ended back in original position. I wouldn't have thought it to be a contributary factor, but who knows for sure.

Guest Brian Robson
Posted

Everything was fitted the way you describe starting at the head and moving backwards. I will try the indivdual pipes as soon as they are made, but I will be saving for a Stucchi crossover; thicker SS and much nicer welding.

Guest Brian Robson
Posted

British Italian have asked MG to cover the parts under warranty. I'm still waiting for a set of Mistrals from eBayUK to arrive (brother in law sent them by surface mail 8 weeks ago :(:( ; I'm hoping they arrive before Christmas!), and hope that their light weight will end these exhaust issues. :)

Guest dkgross
Posted

fwiw..I've got a set of Stock Mufflers and a Stock XOver if anyone needs them..

Posted

After having a stock system for some time I replaced a crossover with Stucchi unit just installing it without paying any attention to relieving stress or any other esoteric manouvers.

 

Nothing cracked. Then approximately a year later i added FBF end cans just slapping them in on the back. They were not very even on both sides so i had to push a little on one side and pull on the other. One triangular hanger ended up on outside and the other inside the factory muffler/pass. footpeg bracket.

 

Obviously the tension was/is there but for a long time now and after many miles of hard riding nothing breaks or cracks and the welds hold like before, fast and strong.

 

The point of all this is that it looks to me like you had some inferior hardware and no matter how careful installation would've not make any difference.

Guest davidb
Posted

After spending 1100$ on a exhaust for my BMW r1100s, I decided to build the guzzi exhaust. I am very happy with the performance and I will work on the noise level next. I had Tomsp from this forum test ride it for his opinion, If anyone here is interested on a Very noticable gain in speed and hard response, you can ride mine or ask (pm) tom about it.

Guest Brian Robson
Posted

I agree with you Janusz, I simply think that the welds were not up to snuff and hopefully the problems will end.

I think it was you I saw riding up in the Shuswap (black V11, FBF cans and soft panniers?) and I can testify to the fact that you ride pretty hard!

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