lawn boy duraforce questions?

[ajc894]

I have a go kart running a R-tek as it's crankshaft is a keyed 3/4 in (Sorry I was wrong when checking this weekend it is 1/2). I have one more laying around as well as a duraforce.
The difference seams to be piston ported vs reed ported

• Is one better then the other?
• would the Toro R-tek crankshaft work in a duraforce?

here a spec sheet
www.biodsl.com/fsm/Duraforce_Service_Manual.pdf
from this it looks as it might. just looking for thoughts

Andrew

 

[OzFab]

 

[rushking19]

It probably won't fit in the duraforce, but the duraforce should make more power, when built
And where's Russ when you need him?

 

[ajc894]

So reed ported is the better power maker? I we tear the two down this weekend.

 

[Russ2251]

Pics not needed and would not help in any case.
Crankshafts are NOT interchangeable.
First time I'm hearing of ¾" PTO. Typically, they are 63/64 ths.
Piston ported snow engines are junk. I'd use a clone or Predator first....that's how bad they are.
As with most 2 cycle snow engines (especially Tecumseh) they are very poor performers. I purchased 2 R-TEK's and used one of them just long enough to make a video.
Both collecting dust (along with an old clone) in my basement.
On the other hand, I have at least eight DURAFORCES. All runners with various modifications. Clone killers all.
There's a couple of guys selling brand new DURAFORCE short blocks on EBAY right now.
I just received 2 of them in factory sealed boxes.

 

[rushking19]

just Use The Duraforce It's A better Choice Russ Have pushed it to around 8-10hp ,it's best to use a tillotson carburetor because it can be used in any position so it will bolt right up or you can install a mikuni with slide throttle and get a clamp type intake manifold .

 

[Rear engine 86]

Not to butt in or hijack this thread, but I'm currently in the middle of this said Duraforce Lawnboy conversion myself.

It sure is alot of work but that's the fun. Mount is being tig welded as I type and I will upload some pics asap.

I'm going the machined crank route as I want to use a Comet Tav on this when done.
After seeing youtube vids and reading about others success with this Im really excited to see the end result.

 

[rushking19]

Not to butt in or hijack this thread, but I'm currently in the middle of this said Duraforce Lawnboy conversion myself.

It sure is alot of work but that's the fun. Mount is being tig welded as I type and I will upload some pics asap.

I'm going the machined crank route as I want to use a Comet Tav on this when done.
After seeing youtube vids and reading about others success with this Im really excited to see the end result.

Good Luck With Your Project I Love To See Lawnboy Duraforce Engines On Go Karts, But I Never Actually Seen One With A Torque Converter Before So It Should Be Awesome When It's Complete

 

[ajc894]

That sounds cool. Got a build thread started?

 

[rushking19]

That sounds cool. Got a build thread started?

Yes but it's for A Go Kart With Snowmobile Engine Build, I Call It Project Rocket Kart

 

[rocketkart]

Yes but it's for A Go Kart With Snowmobile Engine Build, I Call It Project Rocket Kart

what!!! what!!!!!!! im going to have to charge you for the name.

 

[rushking19]

what!!! what!!!!!!! im going to have to charge you for the name.

LMAO I didn't know that you're name was rocket Kart, I Named it Project Rocket Kart Because It's going to be fast as a rocket

 

[Rear engine 86]

Good Luck With Your Project I Love To See Lawnboy Duraforce Engines On Go Karts, But I Never Actually Seen One With A Torque Converter Before So It Should Be Awesome When It's Complete

Hey thanks for the kind words. I am going to start a build thread asap and I would like this to be a hot topic so I will post lots of pics and be on here as much as I can.
I have only seen one of these converted engines use a cent clutch myself and after reading about how Fast Eddie machined his cranks, I just had to include a Tav in my build. Here are some pics.

 

[rushking19]

Hey thanks for the kind words. I am going to start a build thread asap and I would like this to be a hot topic so I will post lots of pics and be on here as much as I can.
I have only seen one of these converted engines use a cent clutch myself and after reading about how Fast Eddie machined his cranks, I just had to include a Tav in my build. Here are some pics.

That Thing Looks Insane, What Type Of Exhaust Pipe Are You Going To Use, Straight Piped,Straight Pipe With Dirt Bike Muffler, Or Expansion Chamber With Muffler?

 

[Russ2251]

When completed, come on over, we'll have a race.

 

[Desertduler]

Oh come on Russ, Two against one is no fair!

 

[Rear engine 86]

That Thing Looks Insane, What Type Of Exhaust Pipe Are You Going To Use, Straight Piped,Straight Pipe With Dirt Bike Muffler, Or Expansion Chamber With Muffler?

I have been thinking alot about this. The metal shop that tig welded my mount and machined my crank said they can build me pretty much any type of exhaust system I want but obviously $$ is a factor here. I dont have a welder so fabing this myself is pretty much out of the question.

I was thinking a straight 1.25 id pipe with smooth bends comming over top the cylinder and then pointing back with a 3/4 pipe thread at the end so I can screw a large sausage type muffler as I dont want to run a pure straight pipe, way to loud!
This has been my main idea but Im open to other suggestions.

 

[Rear engine 86]

When completed, come on over, we'll have a race.

Lol if they ever invent teleporters, Im in! Oh and soon as I get my second motor built

Have you ever been able to fully top out your dual engine kart?
That thing must pull hard!!
How are the vibrations on these Duraforces compaired to lets say a flathead briggs or clone?

In the dirtbike world, 2 strokes sure like to buzz ya lol.

 

[Desertduler]

I have been thinking alot about this. The metal shop that tig welded my mount and machined my crank said they can build me pretty much any type of exhaust system I want but obviously $$ is a factor here. I dont have a welder so fabing this myself is pretty much out of the question.

I was thinking a straight 1.25 id pipe with smooth bends comming over top the cylinder and then pointing back with a 3/4 pipe thread at the end so I can screw a large sausage type muffler as I dont want to run a pure straight pipe, way to loud!
This has been my main idea but Im open to other suggestions.

The single biggest performance enhancement for a two stroke is an expansion chamber bar none, but it needs to be designed for the particular engines port timing and the RPM level of the engine to where the peak power curve is. If you do not have the resources and tools to build one then you will have to settle for something with less effect.

 

[Rear engine 86]

I was at the metal fab shop a fiew hours ago and turns out he is abit behind on the machine work to the crank. He was tig welding my mount as I was walking in. Some more pics. I really hope the crank turns out (lol no pun ) as I expect.