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wwbragg

Please help fabricate exhaust

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wwbragg

I'm repowering a Simplicity 725 with the Harbor Freight 420 13 HP engine (see "flywheel adaptor" in Show and Tell).   To get the hood to fit I have to remove the muffler.  I cut a 2"x2" piece of 3/16 flat stock and, using the original muffler gasket as a template, marked and drilled all the requisite holes.  I was going to weld in a piece of 1-1/4 conduit as the exhaust pipe and then fix a muffler of some kind onto that.  But the walls of the conduit are pretty thin and so I'm wondering if I should use a piece of 1" pipe instead.  The opening on the manifold is 1-1/16 and the opening on the conduit is 1-3/16 so it opens up a little.  The opening on the pipe is 1" and will slightly increase the back pressure but would handle the heat better.  What do the experts think?

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Edited by wwbragg
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GregB

Maybe source some 1 1/4 ID Pipe if you are worried about changing flow?

 

What ever you do make sure to remove a good bit of the galvanized coating before you weld.  Not good to breath those fumes.

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lugnard

Might just go to a muffler shop or someplace that does muffler fab. work and use a chunk of exhaust pipe. They probably have some cut-offs they would give you. Would probably weld better and hold up over time.

Harry

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wwbragg

The muffler shop charged me $80 for a custom exhaust on my 707.  Not a bad price, I guess, but it took forever 'cause he only worked on it between other jobs.  I didn't know there was 1-1/4 pipe.  I thought the next size was 1-1/2.  But I checked at the local hardware store and there it was.  Since I have to grind off the galvanized coating anyway,  I'll just grind off the threads.  Should fit right in the existing hole.  Thanks for the help, guys.

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MikeES

I have gone to the muffler shop and had them use a piece of scrap a couple of feet long and put a 90* bend in it.   Only cost a few bucks.  At home I cut to length and welding as needed.

Edited by MikeES

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wwbragg

599f6d32be66b_2013-10-3123_05_34.thumb.jpg.31176820d6b7c0c563ef693824fb1e98.jpgI wanted to make a dual exhaust and use VW exhaust tips for muffling but my welding skills are sorely lacking and my son couldn't do much better.  So I bough a Harbor Freight pipe bender, put a wiggle in a length of conduit, and had the guy at the machine shop weld it onto the flange I showed previously.  Then I went to the cycle shop where the guy sold me a used Harley Davidson muffler.  When I fired it up, it throbs so I need to adjust the govenor.  I think it is too much muffler so now I'm thinking maybe a single VW exhaust tip but that would reduce the exhaust passage from 1-3/8 down to 3/4 inch.  Will that choke it up too much?????

Anyway, here is the "finished" item.  Keep in mind that tractors are like combat foxholes, they are never really done.

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2013-11-09 00.47.59-1.jpg

Edited by wwbragg
choke/ govenor
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MARK (LI)

Now that looks sharp!  That is one cool looking tractor....how is that predator engine?

Despite your claim that your welding is not super, you show some real talent and stick to it attitude

Edited by MARK (LI)
thought of more to say

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wwbragg

Thanks for the kudos, but the guy at the machine shop did the final welding.  Never the less, I will  "never give up; never surrender."  (from Galaxy Quest).   As for the engine, it ran fine until I put the muffler on.  I was afraid of increasing back pressure but I think maybe I don't have enough.

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wwbragg

I took this muffler from one of my old Landlords.  It runs (and sounds) better so I'll order a new one so it looks better.  But I still have to keep the choke at half open. Will the high altitude jet fix this?

2013-11-09 18.16.13.jpg

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