Tecumseh HS40 crank shaft wanted

Loren65GS

Loren65GS

Member
#1
#1
I'm still searching for a crank shaft for my HS40 to go in my Fox Street Scamp. I need the crank shaft with the 3" PTO. Many years ago Marcus gave me the numbers of the crank shafts. The following is Marcus's quote from that post.

The actual engine Fox used was an HS40-55266B the part number for that crankshaft is 33012 and works with the bushing sidecover engines.
Rupp engines were HS40-55388C the part number for those cranks are 33080 BUT they are Ball Bearing supported and the fox engines were not so you also will need the sidceover 30756B (correct original number, late model version/updated part number is 30756C), and of course the bearing, and C clip etc. in order to use one of those.

Thanks for looking,
Loren
 
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cfh

Well-Known Member
#4
#4
Your message is a bit confusing... do you want a ball bearing rupp style crank? even though your Fox hs40 is bushing style? you want to convert to ball bearing? why do you want to do that? the ball bearing thing is cute, but frankly, the juice is not worth the squeeze unless you're spinning high RPMs (slide carb/big cam/open exhaust, etc.) Because like Mark said, you'll need to find a hard-to-get crank, hard-to-get side cover too. And why do you want to do this? Especially since the Fox never had these things.

Also why do you need a 3" long Pto? yes i know rupp did that, but again, why? a 2 1/4" Pto (drilled/tapped) works find with any torque converter. are you racing this bike? it seems doubtful, or you would be using an HS50...

i build high rpm HS50 engines all the time for my bikes. i rarely ever use a ball bearing side cover/crank. haven't had a single problem yet. and i almost always have a 2.25" pto also, with a style 20 or 30 torque converter. just saying you may be going over kill, unless you have some special application going on here.
 
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markus

markus

Well-Known Member
#5
#5
cfh said:
Your message is a bit confusing... do you want a ball bearing rupp style crank? even though your Fox hs40 is bushing style? you want to convert to ball bearing? why do you want to do that? the ball bearing thing is cute, but frankly, the juice is not worth the squeeze unless you're spinning high RPMs (slide carb/big cam/open exhaust, etc.) Because like Mark said, you'll need to find a hard-to-get crank, hard-to-get side cover too. And why do you want to do this? Especially since the Fox never had these things.

Also why do you need a 3" long Pto? yes i know rupp did that, but again, why? a 2 1/4" Pto (drilled/tapped) works find with any torque converter. are you racing this bike? it seems doubtful, or you would be using an HS50...

i build high rpm HS50 engines all the time for my bikes. i rarely ever use a ball bearing side cover/crank. haven't had a single problem yet. and i almost always have a 2.25" pto also, with a style 20 or 30 torque converter. just saying you may be going over kill, unless you have some special application going on here.
Click to expand...

The extended PTO was used/needed on the Fox street scamp/trail tramps due to the extra wide 2 speed clutch assembly. Even with 3" PTO, they still had to use a spacer in order to fit them.
 
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cfh

Well-Known Member
#6
#6
ok makes sense thank you!
there may be another idea. it's not as clean, but it would get the situation a resolution, without spending too much money. Get a late model Tecumseh LH195 engine with the 7/8" pto off a snowblower. it's a little bit of work, but i have done this.... take out the crankshaft and turn it down to 3/4" on a lathe, and re-cut the 3/16" keyway. You will end up with a 3.25" pto. I've done this a bunch of times and it works well. You will also have essentially an HS50 engine. You can change the new style cyclone blower housing to an older 4-leg pull start style housing. This will roughly keep the old school look (though you won't have the fully rounded pre-1973 blower housing, but it's still a pretty close "look".) Anyhow, that could all be done for minimal money.

another approach is to just get an LH195 crankshaft (pto cut to 3/4") and install it in any CDI tecumseh hs50 like model E or F, or later. that would probably work too.

it's not the perfect solution, but it will get you riding the bike with a 5hp motor, and approximately the same look/feel as the original HS40 engine (assuming you paint the motor white.) that way you can still have a fun bike until you find that unicorn #33012 hs40 crankshaft.
 
Ginz61

Ginz61

#7
#7
I don’t know if 1” diameter 3” long pto hs40 cranks exist or not but I recently had 2 1/4” 1” diameter hs40 crank turned down to 3/4” and a keyway cut for use on 1 of my minis and it worked out great. The machinist I used said he’s done this and similar jobs(like CFH) many times and did a beautiful job. That’s where we’re at now with hs40’s since the parts are so scarce. Luckily guys like the man that did it for me and CFH exist.
 
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cfh

Well-Known Member
#8
#8
i got a bunch of $30 tecumseh LH195 engines in the past off snowblowers. they have 7/8" diameter PTOs and they were 3 1/4" long! turned them down to 3/4" diameter and cut the keyway. Then had to cut them shorter because there were longer then the torque converters i was using! and you end up with a 5hp motor that looks just like an HS40. win-win for me.
 
Ginz61

Ginz61

#9
#9
cfh said:
i got a bunch of $30 tecumseh LH195 engines in the past off snowblowers. they have 7/8" diameter PTOs and they were 3 1/4" long! turned them down to 3/4" diameter and cut the keyway. Then had to cut them shorter because there were longer then the torque converters i was using! and you end up with a 5hp motor that looks just like an HS40. win-win for me.
Click to expand...
First off CFH I have massive respect for you and your knowledge. I’ve read and re read most all of your stuff on your site. I seem to remember reading that you said not to use a hs50 crank in an hs40 because they’re different. Since the lh195 crank is basically a hs50 crank I’m just wondering what’s changed. Again I’m not doubting you at all, just an attempt at learning for the future. Also I really like the idea of a 5hp in a 4hp clothing.
 
Loren65GS

Loren65GS

Member
#12
#12
Definitely some good ideas have been suggested but I already have the HS40.
A member has messaged me that he has a ball bearing style crank. Anyone have the ball bearing cover for this crank? Buying his crank and the correct cover would solve my issue.

Loren
 
Loren65GS

Loren65GS

Member
#19
#19
Loren65GS said:
LOL.
You would think someone would have the cover.
Ok, question, is the cover HS40 specific or interchangeable with another size engine like HS50?
Thank you guys,
Loren@65GS.com
Click to expand...
After a bit of research and reading I have my answer to my question. Many thanks to the members here. The covers interchange ! Also came across very excellent information in the HS40 cyl cover thread started by copyman. With some very good references from cfh and Ginz61.
Many thanks to all contributors.

Loren@65GS.com
 
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cfh

Well-Known Member
#20
#20
part of the problem is you can take a regular bushing crank and easily turn it on a lathe to become a ball bearing crank. but the side cover, that you can't convert or make. so it will always be harder to find a ball bearing side cover, because for all practical purposes, there is a huge potential amount of ball bearing cranks. but again, i still don't understand the need for ball bearing cranks. i mean at this point (we're all 40 years old and older), do we really need a ball bearing crank? we're not 10 year olds spending the entire day trying to throw a rod on our favorite mini bike! ha!
 
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