Robin duel exhaust

/ Robin duel exhaust #1  

elderlyphart

Member
Joined
Jul 27, 2015
Messages
29
Location
yacolt wa
Tractor
power trac pt425
Interest was expressed in my exhaust system so give I'll it a go...
I pulled the stock boat anchor off and observed the square pipe welded to the flange at the exhaust port was way SMALLER than the ex port on the head. My way of thinking is that just ain't right so decided to build the mess you see in the pictures.
I'm one of those guys that builds everything I can from whatever old junk I have around and this setup could have looked way different depending on whats in the junk pile.
Laid out my "origin unknown" shorty mufflers and figured where the pipes had to go. Couldn't come up with any u-bends tight enough. So made my own out of 90 degree pipe. Don't remember the size but it is the SAME diameter as the port in the head. I could go out and measure it if anyone cares. If I was to do it again I would get some pipes and maybe some mufflers also from a motorcycle wrecking yard. Some old dirt "scrambler" bikes had high pipes with a tight bend. Plus CHROME plating!!! That would be really cool!
Finding a muffler short enough to stay out of harms way might be a problem. I gas welded it all into one solid unit. Mounted the rear of the muffler with some of that flexible canvas type stuff they hang tail pipes with so vibration and movement for heat etc didn't break things. Been on there maybe 50 hours and holding just fine.
The rear bumper was really just a way to mount the mufflers and protect them. Just happened to have a hunk of steel the right length. Could have done it some other way just as well. Whatever works.

The round chrome thing on the engine shroud is an inspection cover. Had those little snap in things laying around so used a hole saw and presto I can see if there is any grass building up in the cylinder fins. Or at least I hope I can see where the grass builds up. Not 100% confident I can but I think so.

Behind that little triangle white paint is my gas shutoff. I use a tube with slots in the end to reach in there so I don't have to lift the eng cover. Man I'm lazy in my old age.

kermit2.jpgkermit3.jpgkermit4.jpgkermit5.jpgkermit6.jpgkermit7.jpg
 
/ Robin duel exhaust #2  
Looks really sweet! :cool2: Thanks for showing the pop off inspection covers; it gives me ideas!

I'm really impressed with the free hand gas welding.

I don't think of it as being "lazy in my old age". I like to think of it as wisdom and cunning. :thumbsup: Those engine covers don't get lighter with each passing year.

Thanks for sharing!

All the best,

Peter
 
/ Robin duel exhaust #3  
Like your mods! I hope to get mine running soon so I can begin mods myself.
 
/ Robin duel exhaust
  • Thread Starter
#4  
Well now dang it I done got caught lying. The weld in the middle of the head pipe is not mine. (but the weld to the mufflers and engine head flange is.) I need better memory pills.
Check out the horrible weld on the u shaped thingie for the pipe to come through the engine cover. Used a cutting torch and grinder to make that.
Hang my head in shame...

Something else in those pictures. Can anybody identify it?
 
/ Robin duel exhaust #6  
Nice job.

The mesh on your engine cover looks a lot more open than mine (2005), which has gotta help the under hood temp a bit.
 
/ Robin duel exhaust #7  
The broadsword sheath on the engine cover?

All the best,

Peter

Well now dang it I done got caught lying. The weld in the middle of the head pipe is not mine. (but the weld to the mufflers and engine head flange is.) I need better memory pills.
Check out the horrible weld on the u shaped thingie for the pipe to come through the engine cover. Used a cutting torch and grinder to make that.
Hang my head in shame...

Something else in those pictures. Can anybody identify it?
 
/ Robin duel exhaust #8  
So question about the 425 crowd. Could you put the muffler on the top of the engine? Keeping it in the compartment? Or is there a reason not to? Seems like there is some serious headspace in the engine cage.
 
/ Robin duel exhaust
  • Thread Starter
#9  
Heat! Robin in a tub gets hot. You diesel guys get to point and laugh at us poor Robin guys.
Speaking of laugh, I LOL'ed out loud at Peter's post. Turned the tables on me. Just what the heck is a "broadsword sheath" ?
Had to google it. Mama made it for me. It holds a jagged tooth sharp saw to deal with them pesky limbs one encounters cruising the forest. Put a u shaped plastic pcv channel in there to keep from sawing through mamas hard work. Also got a length of plastic sewer pipe on there to hold shovels rakes and so forth. Plus a rubber strap across the roll over thing to hold things.
I look like a hardware store on wheels when I get it loaded up. Not to mention the cool beer can holder.
Anyway still nobody sees the mystery item in the pictures.
Big hint- my Dad used to scowl and say a lot of bad things about them clear back 70 years ago.
 
/ Robin duel exhaust #10  
Did you cut off your seatbelt to use in another project? ;)
 
/ Robin duel exhaust
  • Thread Starter
#11  
Naw, that seat belt is still there. Tucked in the crack between the sections. Only time I dig it out is on the somewhat steeper slope out front. The thing that worry's me is getting in the seat with the engine running. That might smart to run over myself. I be VERY careful.

To add to woodlandfarms answer - the reasons for going to duel pipes: (1)- get rid of the crossover pipe radiating heat between the 2 cylinders. Get the heat out of the engine compartment as fast as possible. And
(2)- Duel pipes are way cool.
Big bonus - a noticeable increase in power. More power is also way cool.
Also it sounds more like an engine should sound. That is also way cool.
Uh huh... Way cool. :)
 
/ Robin duel exhaust
  • Thread Starter
#12  
Another unexpected thing.
Figured the way bigger volume of exhaust tubing and mufflers would provide a more "lazy" exhaust pulse out the rear of the mufflers.
Was rather surprised that the pulse is very strong and you can see it bend the grass out a few feet at times. Even with the exhaust pointed straight back. That tells me the stock setup is way restrictive and the duel setup is not overkill like I thought it might be.
 
/ Robin duel exhaust #13  
I want that old car/truck in the background. What i can see looks like a sweet ride.
 
/ Robin duel exhaust
  • Thread Starter
#14  
Ding Ding we have a winner! Ya spotted the mystery item!
That's "old enema orange" my 34 Ford hot rod. It's got lotza horsies.
I wash it maybe once a year. And drive it like I stole it.
Ton of fun.

Kermit the robin powered frog is also a lot of fun. Between the two of them it keeps me from vegetating in the recliner.
 
/ Robin duel exhaust #15  
I bet it does. My mini cooper convertible and my faux John Deere power-trac keep me happy as well. My PT always gets looks from people driving by. I really love driving them both.
 
/ Robin duel exhaust
  • Thread Starter
#17  
PM sent
Receiving it is another matter. PM's are new fangled technology to me.
 

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