1971 MTD HS-50 exhaust

Sprocket86

Sprocket86

Active Member
#1
#1
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I rebuilt my 1971 MTD 520 minibike and I'm having trouble with the factory style exhaust pipe for the Tecumseh HS50 engine.

I purchased a Taylor PN#33224 exhaust pipe thinking it would fit. Although it fits the engine and carb/air cleaner, the end can was to far to the right and it hit the frame.

How many different Taylor or Tecumseh HS50 slant exhaust pipes did they make?

Anyone know what part number mine is for or what is the correct one is for my MTD?

Thanks for your help.
 
1

1971_MB1A

Well-Known Member
#2
#2
Well for one thing I see is that for starters it looks to me like you may be using the wrong style engine that would be period correct for that bike and are you sure it even originally came with a 5 hp Tecumseh ? I have several MTD's like/similar to yours and most of them just have 3-4 hp Tecumsehs on them and the few I have with 5 hp Tecumsehs have the larger spoke wheels with the earls style front end. Just putting that out there.
 
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Sprocket86

Sprocket86

Active Member
#4
#4
1971_MB1A said:
Well for one thing I see is that for starters it looks to me like you may be using the wrong style engine that would be period correct for that bike and are you sure it even originally came with a 5 hp Tecumseh ? I have several MTD's like/similar to yours and most of them just have 3-4 hp Tecumsehs on them and the few I have with 5 hp Tecumsehs have the larger spoke wheels with the earls style front end. Just putting that out there.
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Your correct in saying that I'm using the wrong engine on this mini as I'm not sure if the HS50 was available on these bikes.

From my understanding, the Tecumseh HS40 and HS50 both use the same reverse intake and exhaust ports and were always slant mounted on these bikes.

Do you collect this make and model of mini bike?
 
1

1971_MB1A

Well-Known Member
#5
#5
I'm fairly certain the HS50 slanted intake is unique to only that application but not totally certain as to the exhaust port part of it so I would probably just ask one of the experts on here about that part of it such as SimpleTom or markus as I'm sure they would know. I'm just mainly going by what I have seen on a few of my original survivor MTD's. If for some reason you don't get it all worked out I could probably hook you up with a vintage application complete HS40 MTD correct engine,exaust etc and if so just PM me and we can go from there. I don't collect just MTD's. I have somewhat of a variety of several different bikes.
 
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Sprocket86

Sprocket86

Active Member
#6
#6
1971_MB1A said:
I'm fairly certain the HS50 slanted intake is unique to only that application but not totally certain as to the exhaust port part of it so I would probably just ask one of the experts on here about that part of it such as SimpleTom or markus as I'm sure they would know. I'm just mainly going by what I have seen on a few of my original survivor MTD's. If for some reason you don't get it all worked out I could probably hook you up with a vintage application complete HS40 MTD correct engine,exaust etc and if so just PM me and we can go from there. I don't collect just MTD's. I have somewhat of a variety of several different bikes.
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You'd be correct in saying that the HS50 slanted intake is unique to this application but I've sent a PM to one of the members you mentioned above. I'll see what I hear back.

I'll keep my eye open on the Ebay and on here. Thanks a lot and I really appreciate that.

Right on and I'm starting to build up quite a bit of vintage mini bike parts myself. I'll PM you
 
markus

markus

Well-Known Member
#7
#7
The old tecumseh book lists #33346 as being a slanted spark arrestor taylor muffler with MTD listed as the only customer name, Its for an HS40. Does not give listings of bikes they were used on, just a customer name. It looks like MTD used a couple different styles (one at least was thier own) possibly depending on model or year made. I dont know if the part number would be stamped on it or not so that part number may not help it lists the muffler position a 5 degrees, where the 33224 is listed at 90, so that should put it up and more centered not off to the side.

None of the HS50 specific slanted headers listed in my parts book show MTD as a manufacturer that used/ordered them

remember HS40 and HS50 engines have different port configurations on the exhaust (intakes as well of course), they will cross fit, but not very well as the inlet size is different, the ports dont line up, and sealing surface gets lost.

Left HS50, center HS40, Right H25-30-35

 
Sprocket86

Sprocket86

Active Member
#8
#8
Thanks for this great write up markus.

I had a feeling the HS40 and HS50 exhaust ports were different and your Tecumseh manual data verifies that these MTD mini bikes didn't come with HS50 power.

So what I'm trying to accomplish here will technically never be correct. Maybe I should just stick with my modified 33224 pipe and call it quits lol. I really like the factory exhaust set up on these bikes with the chrome large diameter extension pipe center mounted over the back fender.
 
Sprocket86

Sprocket86

Active Member
#9
#9
That's a beauty collection of Tecumseh exhaust pipes you've got there.

How many different ones did the make? It seems like I'm always seeing a slightly different one.
 
markus

markus

Well-Known Member
#11
#11
Might want to check this out, not sure if the part number would be visible anymore for the seller to see but it is a true HS50 version though. not sure if you can get anything from the pictures to see angles, etc..stated is off an MTD so maybe he can tell you how it fit or what version mtd it was at least. The engine he has for sale is NOT a match for it, its a standard mount (but is true mini bike). I grabbed the slanted HS50 intake he had listed, its black in color originally like the head thats on the engine, so it may be worth asking for the numbers off it as maybe that block was used as a replacement. If they are the slanted style numbers it will have a allen type drain plug listed for the rear, single fill sidecover, and of course the 33669 intake


https://www.ebay.com/itm/tecumseh-m...ash=item25f3db6e53:g:Rq0AAOSwkRha1ttx&vxp=mtr
 
Sprocket86

Sprocket86

Active Member
#12
#12
Hey thanks for the Ebay link.

It's hard to tell from the pics what angle or offset the pipe is compared to my 33224 Taylor exhaust pipe.

Is the 33224 Taylor pipe listed for an HS-40 or HS-50?

I'm at work currently and I'll message the seller asap. Hopefully he can provide some more details.

That's sweet you snagged the ultra rare 33669 HS-50 slant intake manifold. Another into the collection lol.

It's funny you mention the mini bike specific block oil drain and refill. The engine that's on my MTD has those exact features but I know it came from a late 70's or early 80's snow blower.

Up here in Canada we've got a great selection of potential donor flathead Tecumseh engines from snow blowers for mini bike use. Most have fairly low hours and never sucked dirt haha.

I'll post my fan shroud numbers on here. Perhaps you could break it down for me?
 
Sprocket86

Sprocket86

Active Member
#14
#14
markus said:
33224 is an HS40 exhaust.
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Kinda thought so.

I messaged the seller and the pipe is from an MTD trailflite mini bike with the springer front end and spoke wheels.

I have a feeling it's the exact same 33224 pipe that I already have. I can't seem to get a answer if this is a true HS-50 pipe.
 
1

1971_MB1A

Well-Known Member
#15
#15
Right that's correct the MTD trailflite with the earls style springer front end and spoke wheels was available with a 5HP Tecumseh but NOT the style like yours. I have a "very rough" but all original spoke wheel/earls style springer front end MTD that still has it's original 5HP Tecumseh lighted engine and the original color is yellow.
 
pomfish

pomfish

Well-Known Member
#16
#16
1971_MB1A said:
Right that's correct the MTD trailflite with the earls style springer front end and spoke wheels was available with a 5HP Tecumseh but NOT the style like yours. I have a "very rough" but all original spoke wheel/earls style springer front end MTD that still has it's original 5HP Tecumseh lighted engine and the original color is yellow.
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Is the front wheel a 12" on your 5hp?
 
Sprocket86

Sprocket86

Active Member
#17
#17
1971_MB1A said:
Right that's correct the MTD trailflite with the earls style springer front end and spoke wheels was available with a 5HP Tecumseh but NOT the style like yours. I have a "very rough" but all original spoke wheel/earls style springer front end MTD that still has it's original 5HP Tecumseh lighted engine and the original color is yellow.
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So I need to find the correct HS-40 slant minimal offset pipe for my bike then. I wonder what the PN# is for that pipe?


Did you ever get my email?
 
1

1971_MB1A

Well-Known Member
#18
#18
Yes I did get your email but been very busy so I never got around to digging that stuff out to do the pics yet but I will If you still want them. Sand N Snow bike,HS40 Trailflite exaust and 5HP Tecumseh MTD exaust correct ?
 
C

cfh

Well-Known Member
#20
#20
There are at least 6 different Taylor product mini bike exhausts. The options i see are the port (HS50 has an offset bolt pattern, compared to say HS40). and then of course the angle of the dangle on the pipe itself.

Since original Taylor product exhausts are a bit expensive and don't come up for sale often enough, i was thinking of re-making them. Have a web page where you pick your option, to build your exhaust... pick the port style (HS3/4/5), and the the bend degrees, and maybe have an option for overall length too. i thought it was a great idea until i went to the fab shop to get a price. Damn it's not going to be cheap (probably $25 to $30), so i'm not sure it's worth it.
 
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