Considering a LB powered kart

[redsox985]

Considering a LB powered minibike

So, I was interested in making a minibike this summer, probably a speed bike, so I was thinking about using a 2 stroke motor, a LB specifically. So I looked on my local CL and got TONS TONS TONS of hits.

http://pittsburgh.craigslist.org/search/sss?query=lawnboy&srchType=A&minAsk=&maxAsk=

I especially these.
http://pittsburgh.craigslist.org/grd/2278121927.html
http://pittsburgh.craigslist.org/grd/2238416888.html
http://pittsburgh.craigslist.org/grd/2307291093.html

 

[Bluethunder3320]

wow. if i was you id grab 4 or 5 to mess with.

 

[Doc Sprocket]

Lucky you! I tried for YEARS to scoop one at a decent price! I'm hoping to make a deal on one in a few weeks when the owner decides which of two he wants to keep.

Anyway, good luck!

 

[Russ2251]

Be careful...there is only a limited number of L-B engines that will work for gokart/mini bike related stuff.
Anything labeled Duraforce would be optimum and should be immediately grabbed up.

I tried for YEARS to scoop one at a decent price!

I have paid as much as $130 (delivered) for a Duraforce in unknown condition...that's how confident I am in their performance...Klone Killers.

 

[karl]

My grandpa has 6 older lawn boy push mowers :toetap05:
I HAFT TO GET ONE

 

[redsox985]

So, Russ, I should look for a Duraforce series LB? What all must be done for them to run horizontal? Reorient carb, move gas tank, file keyway, and make a mount. Is that it?

 

[Russ2251]

So, Russ, I should look for a Duraforce series LB? What all must be done for them to run horizontal? Reorient carb, move gas tank, file keyway, and make a mount. Is that it?

Very basically, yes. It is a lot of work.
Keep in mind that a usable clutch is over $120.
To use a less expensive clutch would mean that shaft would have to be ground down to ¾".
One very important thing is that kart should be kept as light as possible.
My single engine kart only weighs 130 lbs. complete.

 

[Bluethunder3320]

russ, couldnt you run a 1" ID sprocket on the engine onto a 3/4 jackshaft, and have the clutch on the other side?

a jackshaft, sprockets, and chain would probably end up not saving a huge amount though.

 

[Doc Sprocket]

More cost, weight, complexity, inertia load, and maintenance.

 

[Russ2251]

I will not entertain the thought of "jerk" shafts.
They are too heavy, complicated, cumbersome, expensive...not to mention the power losses that are attributed to such constructions.
I am an old school kart builder and have no time for bolt on's.
I prefer the simplicity of 1 chain and 2 sprockets (clutch/axle).

 

[redsox985]

So the usable portions of the shafts are 1"? Could it be turned down to 3/4" with a lathe? If I could get one before school ends, I could easily bring it into school and use a lathe to turn it down and then mill a keyway into it saving myself lots of time and effort.

 

[Bluethunder3320]

you would probably be safe with a 3/4 shaft since they dont make huge amounts of power to need a 1"

 

[Russ2251]

Duraforce shaft is 63/64ths inch. Engine models prior to Duraforce are 7/8ths inch.

 

[Bluethunder3320]

i have heard of 7/8" bore clutches before. a 63/64 would take a 1" just fine though right?

 

[Russ2251]

a 63/64 would take a 1" just fine though right?

Nope, needs .007" stainless shim to make up the difference.

 

[redsox985]

In that case, I may look pretty hard so that I can go into school with the PTO and lathe it down to .748 or whatever the clutch fits snugly over. What are the tolerances on a decent (3/4" bore probably in the sub $100 range) cent. clutch's bore? And if nothing pans out on CL, I have a friend whose dad owns a landscaping business so he said I could probably pick one up from him for about $50.

EDIT: Just made an attempt to contact those 3 links I posted yesterday asking about DuraForces. We'll see how it goes.

No --> http://pittsburgh.craigslist.org/grd/2238416888.html

New leads:
http://pittsburgh.craigslist.org/grd/2319842713.html
http://pittsburgh.craigslist.org/grd/2249240736.html

 

[Doc Sprocket]

Keep us in the loop on this one!

 

[redsox985]

Well, my friend said they can probably just give me one for free that they have that doesn't run so it looks like I may be doing some work first. But I'll sacrifice time and a few split knuckles trying to get a free motor working. Especially a 2 stroke, they're so much simpler (is that a word). Although I may have a few leads on running DuraForces.

 

[redsox985]

Well, I got another answer from the second link from an hour or so ago. It's a DuraForce for $30 but it leaks oil. Russ, how tough of a fix would you estimate this to be?

 

[Russ2251]

....can probably just give me one for free that they have that doesn't run...

Sometimes they quit for the dumbest reasons and can be restored to running condition by the easiest of means...at no cost.