HS 40 punch out

Mini Bike & Go-Kart Parts

#21
My buddy tells me one of the last 4hp Tecumseh's made (he called them"powersports" ) says I should find one of those. Will my recoil cover fit on this?
No. Not even close. You need to either do all of that machine work, or get a points type engine and swap the parts over if you intend to use that shroud.
 

cfh

Well-Known Member
#23
about 1975 Tecumseh changed to cast iron flywheels. now they had one flywheel for pretty much all the h35, hs40, hs50 models. but the flywheel is bigger. so all the motors got the new square blower housing. Your engine has the older style rounded housing (and alloy flywheel), which is cool, better look. if you want to retain that housing and look, you need to find a 1983 or earlier points/condenser HS40 replacement engine. then you can transfer your original aluminum flywheel to the new motor, and use the old round top blower housing.

i'm not a fan of the powersport motors myself. they are much newer too, 1990s and later. but they cheated on those motor in my eye. i have a HS40 powersport, and it's bored as an h35. they put in a bigger cam to make it 4hp (so it appears to me.) Me thinks maybe environmental issues pushed this decision. i would much rather have an older HS40. Also any Tecumseh motor about 1988 and newer will have the 'cyclone' style pull start. it's a dead giveaway that the motor is newer. personally i don't like that look (over the 4 leg old style pull start housings.)

Another thing you could do is get a 1983 or earlier points/condenser HS50 motor. Again you could transfer your HS40 flywheel and blower housing to this engine. it looks exactly the same as the HS40, but obviously it's 5 horsepower. HS50 motors in that era are actually easier to find than HS40 engines. It would give you the old school look, a fresh motor, and more power. That's what i would do. The carb and exhaust should bolt right on too.
 

bbiggs54

Active Member
#24
about 1975 Tecumseh changed to cast iron flywheels. now they had one flywheel for pretty much all the h35, hs40, hs50 models. but the flywheel is bigger. so all the motors got the new square blower housing. Your engine has the older style rounded housing (and alloy flywheel), which is cool, better look. if you want to retain that housing and look, you need to find a 1983 or earlier points/condenser HS40 replacement engine. then you can transfer your original aluminum flywheel to the new motor, and use the old round top blower housing.

i'm not a fan of the powersport motors myself. they are much newer too, 1990s and later. but they cheated on those motor in my eye. i have a HS40 powersport, and it's bored as an h35. they put in a bigger cam to make it 4hp (so it appears to me.) Me thinks maybe environmental issues pushed this decision. i would much rather have an older HS40. Also any Tecumseh motor about 1988 and newer will have the 'cyclone' style pull start. it's a dead giveaway that the motor is newer. personally i don't like that look (over the 4 leg old style pull start housings.)

Another thing you could do is get a 1983 or earlier points/condenser HS50 motor. Again you could transfer your HS40 flywheel and blower housing to this engine. it looks exactly the same as the HS40, but obviously it's 5 horsepower. HS50 motors in that era are actually easier to find than HS40 engines. It would give you the old school look, a fresh motor, and more power. That's what i would do. The carb and exhaust should bolt right on too.
Wow thanks! This is information that only can come for those who know! Valuable, thanks everyone, we'll see where this goes. Tyler rides a high performance Honda dirt bike, so the interest lies in riding around on a Cat with his grandpa, not in going fast so the governor will stay on. His bike deserves a decent restoration, it was a very nice roller, just hope I can find the parts that were sold off of it.
 

markus

Well-Known Member
#25
about 1975 Tecumseh changed to cast iron flywheels. now they had one flywheel for pretty much all the h35, hs40, hs50 models. but the flywheel is bigger. so all the motors got the new square blower housing. Your engine has the older style rounded housing (and alloy flywheel), which is cool, better look. if you want to retain that housing and look, you need to find a 1983 or earlier points/condenser HS40 replacement engine. then you can transfer your original aluminum flywheel to the new motor, and use the old round top blower housing.

i'm not a fan of the powersport motors myself. they are much newer too, 1990s and later. but they cheated on those motor in my eye. i have a HS40 powersport, and it's bored as an h35. they put in a bigger cam to make it 4hp (so it appears to me.) Me thinks maybe environmental issues pushed this decision. i would much rather have an older HS40. Also any Tecumseh motor about 1988 and newer will have the 'cyclone' style pull start. it's a dead giveaway that the motor is newer. personally i don't like that look (over the 4 leg old style pull start housings.)

Another thing you could do is get a 1983 or earlier points/condenser HS50 motor. Again you could transfer your HS40 flywheel and blower housing to this engine. it looks exactly the same as the HS40, but obviously it's 5 horsepower. HS50 motors in that era are actually easier to find than HS40 engines. It would give you the old school look, a fresh motor, and more power. That's what i would do. The carb and exhaust should bolt right on too.

The only info that is correct in all of that was they went to the different recoil style in 1988!

@bbiggs54 A donor engine would probably be your best bet. you have a Clapped out block+clapped out rod journal, and I would imagine you will find the crank and maybe even the cam journals and case bores in the same condition when all is said and done.

to keep it as simple (and in the long run the most affordable) should you decide to buy a donor engine to rebuild with you want a late 1969-mid 1980 HS40 with a 3/4" output crankshaft with a keyway cut into it.

If you were going to build a hybrid out of an HS50 it would need to be 1972-mid 1980


(1976 or earlier on both HS40 and 50 to obtain the most parts that best match what you already have)

the above you will be able to transfer your current Flywheel over to, which means you can also transfer the shrouding etc.. giving you the smae looks as your currently have

Anything 1981 (and even some late 1980) will most likely have a larger taper crankshaft that is not interchangeable with your version engine. by 1982 the taper was fully swapped on production built engines, even though they used points ignitions systems.

The engine case however can be used right up to the end of HS40 production around 1996/97 The last few years of production will have a smaller Exhaust valve which was a change to all the small frame engines at that time (for emissions standards), thats why when you were able to order a new HS40 engine block still a few years back, the parts list would show that the exhaust valve is included since you got the latest made engine case.


There was never a "powersport" HS40, or HS50 for that matter. Nothing in the Powersport line will apply to your application so don't let that confuse you.

An important note if piecing together an HS is an HS40 and HS50 are not the same engine. For example you should not use an HS40 crank with an HS50 block, or vise versa. the crank is weighted to best match piston each engine uses. Porting does not match, even though you can bolt intake and exhausts up, its like a square peg in a round hole. So you get exhaust leaks, mismatched sizes and ports that have walled area's and flatspots going from a round to more square port disturbing the flow if you were using your existing HS40 parts, and the only thing keeping it from sucking air at the joint.....a little splooch of JB weld and a wider gasket:D You can do it, but it just isn't smart, not only are you creating a weak link, your performance, even in stock forum suffers. So you want to use the right parts for the right short block you choose!

On one of the Hybrids I built in the past (I call them "HS40+10's") Using a 1977 Sears HS50 snowblower engine as a donor with 1970 HS40 parts, I didn't have a spare standard application HS50 intake at the time. So I rolled with the cold application/snowblower one that came with the engine. They stick out like a sore thumb if you are running a Taylor style muffler or header system, but not too terribly bad if using the Box muff covering over top of it. Oh yea, I had to totally re fabricate that muffler too, It was a long gone NOS HS40 muffler from the the early 70's (no extra stamping on the face and no rear supports bracket etc.) so it had a small port that only worked on an HS40 and would have had a huge leak at the bottom since the port is smaller. so I grafted an HS50's backside/flange onto it of another muffler so there would be no leaks or blockages at the port like I had explained about above, I wanted to keep the certain 1970 style that predated the Taylor mufflers and that was the muffler that was used that year.

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#26
I agree with markus, get an other HS40 engine & just put the original side shroud onto the new engine. I used a 1986 Tecumseh - HS40 Engine for my 1971-1972 Steens Taco - Super Trail 100 Mini Bike instead of using a 1971 or 1972 year engine to avoid Points & Condenser like the plague. I did not want to have to deal with timing the engine just to have the exact year engine for my mini bike. But my 1986 model HS40 engine is modified to look like an early 1970's model HS40 engine & most people would not even know the difference (I gave away the secrect dang it, lol). The only time I would not have done this is if I was doing a full complete restore & needed to use all original time period correct parts. But what matters most to me in my opinion is the engine being reliable & getting to have fun riding the mini bike. Its up to you what route you want to take.
 

Attachments

#29
Need some help, the motor on the grandsons Cat needs some work. The piston needs to be replaced with a 20 or 30 over size and the connecting rod as well. I know where and can get the machine work done in Ann Arbor, just need to know if these parts are available. Also help with the decode of this motor plate. I believe this is the original motor to this Cat eliminator, any help would be appreciated. Thank you View attachment 267715
Need some help, the motor on the grandsons Cat needs some work. The piston needs to be replaced with a 20 or 30 over size and the connecting rod as well. I know where and can get the machine work done in Ann Arbor, just need to know if these parts are available. Also help with the decode of this motor plate. I believe this is the original motor to this Cat eliminator, any help would be appreciated. Thank you View attachment 267715
do you have the name and number of the shop in Ann arbor Thanks
 
#31
I got an HS40 Points block that very has little use, the factory cylinder honing marks are still evident. Off a tiller or something, Block,
valve train piston rod would be usable for your redo, but crank is like one inch. Just a hobbyist, so I hope others chime in. Been saving it,
for a rainy day, but that ain't happening. HS40 55513E Ser 8 1818.
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#32
I got an HS40 Points block that very has little use, the factory cylinder honing marks are still evident. Off a tiller or something, Block,
valve train piston rod would be usable for your redo, but crank is like one inch. Just a hobbyist, so I hope others chime in. Been saving it,
for a rainy day, but that ain't happening. HS40 55513E Ser 8 1818.
View attachment 268885
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View attachment 268887
Thanks for the offer see the following post....Bob
 

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