Lawn Boy Duraforce 2 cycle

Sprocket86

Sprocket86

Active Member
#1
#1
I had no idea there was a 2 cycle engine section now, Awesome:thumbsup:

Looks like this would be a good place to post my Lawn Boy project questions and pics.

I'd be nice if 2 strokes were more popular in the mini bike world but I don't mind being the odd man so to speak lol.

Here is some pics from my build.
 

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Sprocket86

Sprocket86

Active Member
#3
#3
Very nice and excellent attention to detail. I've always loved those West Bend 2 cycle engines. I bet it just screams with that open header pipe.

I was out riding my creation today but after some testing and trial runs, I'm pretty sure I still need another Tilly carb. Both I've tried thus far have to large of venturi and won't allow the engine to reach higher rpms.

HL-239b is the one I think will work best baised off other members test conclusions.
 
H

Havasu Dave

Moderator
#4
#4
Sprocket86 said:
I'd be nice if 2 strokes were more popular in the mini bike world but I don't mind being the odd man so to speak lol.
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A few of us use two strokes in our mini bikes. A lot of members who are now gone used them. Since that time, this site has swung more towards overhead valve, out of the box engines.

I have an A400 in a Stellar that runs pretty good. Any 4 or more HP flat head will beat it. But my gawd, it sure sounds good. A tiny bit of pipe blowing smoke and oil and 140 db right in your face while adjusting the fuel mixture! Can't beat it!

One day, I'll put my 580 on a mini bike frame, but it's currently powering a 1962 go kart.
 
Sprocket86

Sprocket86

Active Member
#5
#5
Havasu Dave said:
A few of us use two strokes in our mini bikes. A lot of members who are now gone used them. Since that time, this site has swung more towards overhead valve, out of the box engines.

I have an A400 in a Stellar that runs pretty good. Any 4 or more HP flat head will beat it. But my gawd, it sure sounds good. A tiny bit of pipe blowing smoke and oil and 140 db right in your face while adjusting the fuel mixture! Can't beat it!

One day, I'll put my 580 on a mini bike frame, but it's currently powering a 1962 go kart.
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Oh really I see, to bad they're not still around on here. Things change.

I've always wanted one of those and yes your right, even though they are not all that fast the cool factor is way up!

I'm also into vintage karts myself and currently have a 1962 Rupp Dart A bone.
 
toomanytoys

toomanytoys

Well-Known Member
#6
#6
I started the same project a few years ago. Never finished it. I had a plate made very similar to yours, flipped the carb around, and I stopped.

I also wanted to grab another and do two of these on a go kart.
 
Sprocket86

Sprocket86

Active Member
#7
#7
toomanytoys said:
I started the same project a few years ago. Never finished it. I had a plate made very similar to yours, flipped the carb around, and I stopped.

I also wanted to grab another and do two of these on a go kart.
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Hi there.

I think I remember following your build (if your the same member) and you started to build a custom pipe from old KX80 expansion chambers if I'm correct? I actually copied another members engine mount design (aka Fast Eddie) and he was restoring a Rupp Dart kart and had two of these Lawn Boy Duraforce engines mounted and ready to go. I'm unsure if he ever completed his awesome creation!
 
toomanytoys

toomanytoys

Well-Known Member
#8
#8
Sprocket86 said:
Hi there.

I think I remember following your build (if your the same member) and you started to build a custom pipe from old KX80 expansion chambers if I'm correct? I actually copied another members engine mount design (aka Fast Eddie) and he was restoring a Rupp Dart kart and had two of these Lawn Boy Duraforce engines mounted and ready to go. I'm unsure if he ever completed his awesome creation!
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That wasn't me. I don't know that I ever posted any pictures of mine. It might of been during one of my many hiatus from this site.

I got the idea from watching a youtube video of a guy running one. I have a ton of lawn boys inherited from my grandfather(from the old butter cups up to the modern stuff) and I had a 6.5 Duraforce just like the guy in the video used. I need to revisit this project and get the crank fixed so I can mount a clutch.
 
Sprocket86

Sprocket86

Active Member
#9
#9
I see. That's pretty cool that you have all the generations of LB mower. I have one from the late 80's and it's the best mower I've used so far.

Ya I'd be pretty sweet if you got a LB Duraforce powered mini going too, it's a great minibike engine :)
 
FirePowerMinis

FirePowerMinis

Active Member
#10
#10
A quick mod of a 180 degree headpipe tube puts this over the engine. Old kart pipes are cheap-ish and a torque-tuned version should be perfect for a 141cc LB. I'll be trying one soon, myself.

s-l1600.jpg
 
Sprocket86

Sprocket86

Active Member
#13
#13
FirePowerMinis

FirePowerMinis

Active Member
#14
#14
Sprocket86 said:
That's a good read there and some great information. I'm still on the fence tho if I'm going to pull the trigger on a expansion chamber.

I feel if I make a much better flowing straight pipe with a large muffler, I'll get much better performance. I eliminated the head gasket a few days ago and that made a difference!
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Yes, there may be room for improvement over the pipe in place :)
I was just refreshing my memory on this article about the box jobs. Pretty easy to make or modify.
THE VESPA BIG BOX EXHAUST TEST – Scootering

But, I love the look of a circuit/snail pipe, and am doing one for the mower.
https://treatlandgraveyard.files.wordpress.com/2010/01/garelli-polini-vip-pipe.jpg
 
Fast Eddie

Fast Eddie

New Member
#15
#15
Sprocket86 said:
Hi there.

I think I remember following your build (if your the same member) and you started to build a custom pipe from old KX80 expansion chambers if I'm correct? I actually copied another members engine mount design (aka Fast Eddie) and he was restoring a Rupp Dart kart and had two of these Lawn Boy Duraforce engines mounted and ready to go. I'm unsure if he ever completed his awesome creation!
Click to expand...
Your crank turned out nice. Still have the twin kart project...in boxes. Got sidetracked on other things like we all do. Made a promise to my best bud that the twin LB's will make some noise this year.

I went with KX60 pipes due to clearance issues behind the seat.

Got lotsa build pics of my motors if anyone needs them for reference.
 
Sprocket86

Sprocket86

Active Member
#17
#17
Fast Eddie said:
Your crank turned out nice. Still have the twin kart project...in boxes. Got sidetracked on other things like we all do. Made a promise to my best bud that the twin LB's will make some noise this year.

I went with KX60 pipes due to clearance issues behind the seat.

Got lotsa build pics of my motors if anyone needs them for reference.
Click to expand...
Hey there! Glad to hear that the duel DF engine Kart is still in the works :)

I'd love to see more pics of your build and a link to another site if you don't mind. I sen't a PM last week with a few questions.

Thanks.
 
Fast Eddie

Fast Eddie

New Member
#18
#18
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