Lawn Boy motor on a kart threads here

[jr dragster T]

Yeah I knew I had like a 5 hp low revving 2 stroke mower. BTW I had to tow that thing home over 5 kilometer's behind my bicycle!

 

[kibble]

BTW I had to tow that thing home over 5 kilometer's behind my bicycle!

Ha ha ha!!! I've done that with printers and computers before when I was your age! I would sometimes find them in dumpsters and I would take them home to take apart.

 

[Russ2251]

BTW I had to tow that thing home over 5 kilometer's behind my bicycle!

:nopity:
I love that story.

 

[jr dragster T]

Dont beleive me Russ? I'm 14 and how else do I get stuff home? "Daddy come home from work so we can go pick up a lawnmower" Yeah right, I like to be independant a little bit. BTW I put 580 km's on my bike just last summer. I have to do axle and bearing overhauls every half summer. have snapped steel bike axle's from shear use. Wana see?

 

[Russ2251]

Dont beleive me Russ?

Did not say that nor did I infer it.

 

[jr dragster T]

I love that story.

Sorry but all the yawning and sleeping face's make's it sound like you didnt beleive me.

 

[Russ2251]

Just reminds how when school was closed for snow, parents would say how they walked to school for 20 miles with 5 foot deep snow.

 

[kibble]

 

[Spule 4]

How many people can claim that their day to day mowers date from 1975 and 1979 respectively?

What is really funny is to zip past the line at a mower repair shop near me, the only mowers out front WITHOUT the sissy bar are generally Lawn Boys with the occasional ancient Snapper.

 

[Spule 4]

....anyhow back to the topic at hand.

I have a mower I think would be best to use for this, a 7231 push mower. It has a blade clutch and brake assembly (yuck) and needs a muffler. It runs great and has good compression, just loud with no muffler.

I also chose this as looking at the drawing, I figure this will give me a non threaded shaft end and a key. Drawings here:

http://partsandservice.com/html/Lawnboy/Lawnmower/7231.html

With the shaft, not sure what will need to be done to fit a clutch?

As far as the Tillotson carb, I checked the archives and see that the HL239 carb is the one to go for. Is this a direct bolt on to the LB crank case, or will some effort be required?

Digging for the AL locally now, may have a couple sources for some scrap.

More to come for sure!

 

[Russ2251]

I routinely see L-B's on Ebay dating to '50's and '60's.
An example from mid '60's follows.
Surprising it has no bids with only 2 + hrs left as of this post.
This tells me that it has no collector value as there are so many still in existence.

 

[jr dragster T]

Russ, The LB crank's use rod bolt's? So it's not like a pressed together dirtbike crankshaft?

 

[Russ2251]

Engine you chose may be a problem.
Utilizes BBC system which is a short shaft. May also be an oddball diameter, but I don't really remember.
Clutch I used takes up most of the length of the long shaft models. If it were any shorter, it is doubtful it would work at all.
Remember that upright mounting plate thickness (my design uses 5/16") will take up some of the usable pto length.

 

[Russ2251]

Russ, The LB crank's use rod bolt's? So it's not like a pressed together dirtbike crankshaft?

Only the model M's were pressed together and are useless to me as far as kartability goes. L-B only made them for a couple years and was their only oil injected engine. They were generally more expensive than the other more popular L-B models.
DuraForce (model 'E') crankcase internals:

 

[Spule 4]

Engine you chose may be a problem.
Utilizes BBC system which is a short shaft. May also be an oddball diameter, but I don't really remember.
Clutch I used takes up most of the length of the long shaft models. If it were any shorter, it is doubtful it would work at all.
Remember that upright mounting plate thickness (my design uses 5/16") will take up some of the usable pto length.

Thanks, I will then dig through all my long blocks and build something.

The shaft diamter was JUST under 1", but that may have been me trying to use the calipers outside in the ice and 28 dg weather!

 

[Spule 4]

OK

I dug through the longblock stack.

The problem I see with this is the lack of a key for the shaft for the clutch mounting. How does one get around that?

 

[jr dragster T]

You carefully cut one with your trusty dremel tool

 

[Russ2251]

What model mower is engine from?
I cut my own keyways (with a tip of the hat to Mr. Kibble).
Takes time and a lot of patience with a dremel and small files.
An abrasive stone with oil helps to finish it off.
In this pic, threaded end and short taper were cut off.

 

[Spule 4]

Thanks for the replies. This does make sense.

The long block is an F. Also your mention of cutting off the end answered my next question.

 

[Spule 4]

Anyone ever try a D series motor? They are sweet little motors, if a little low in the HP department.