Need simple 2 stroke ideas

We currently have a kt100 stock appearing.
Can keep up with the sudams.

We need 2 cycle ideas that wont cost a fortune. Dirt bike engines or kart engines. Looking for 30+ HP.

Just a fun class at our local track. No rules. Just has to be a 2 stroke. Small track, so 100hp isn't needed, but 20 HP doesnt keep up.
 
I’d go with a 116. Get a nice weight break if you’re using UAS weight rules and if you’re on the lighter side. In the ballpark of a hearty 29-34 HP. I’ve been led to believe there’s many 116 rotaries, reedjets and TT75’s sitting on shelves because I’ve managed to pick up two 116cc motors in the past two months for relatively cheap.
 
You could run dual Yamaha's. Setup properly they produce smooth strong power for a smaller track.Have Birky build you a dual clutch and hook them together through that and you can set them up 180*off or straight up depending on your driving preferences.
 
Great info guys. I don't wanna go 2) engines, and I like the idea of water cooled.... I have a younger driver who isn't good at carb adjusting on the fly......
 

Yakattack

Member
I am running a yz125/EG 144, ported mid to top...
I run with a lot of big bore/stroked Animals on Alky...
At 50lbs overweight...No problem getting the job done...
But, I converted mine to a Jackshaft 2-1 gear reduction...through the cases...
Bully 3 disc comes in at 4000rpm...electric water pump on speed controller...

Fun little engine... easy to get parts...
I was running a Yz250f bored and stroked... but for my home track it was too much...
 

Hoppy

Member
You could run dual Yamaha's. Setup properly they produce smooth strong power for a smaller track.Have Birky build you a dual clutch and hook them together through that and you can set them up 180*off or straight up depending on your driving preferences.
I think he mentioned "that won't cost a fortune". Dual Yami's with a Birkey isn't a cheap set up. But they are cool! Hard to beat a 116. Lots of them around and speedy for the price.
 
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RDub3

Member
If you could pick up a tag engine for cheap that would do the trick. Especially if you put it on methanol, but even on gas you're looking 28-32hp depending on the engine.
 
tag engines make good opens, built a bunch of them. the leopards have the same port shape as a tt75.. Sudam piston, dual ally carbs, ported/head work.. I can build the ones I have for sale....
 
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I think he mentioned "that won't cost a fortune". Dual Yami's with a Birkey isn't a cheap set up. But they are cool! Hard to beat a 116. Lots of them around and speedy for the price.
Actually, my twin stock Yammi setup was the cheapest around and very much fun! Just ask the guys here in the OVUAS, especially Justin. Ran 2nd to him on a small bull ring. Got the video to prove it! Now, a big, long track would be a different story.

The Birky clutch would be a few $$$. I ran a 3 & 4 disc Bully with no issues.

Brian #89
 

racer223

Member
I agree with Mike. The Leopard cylinder is great, however the X30 cylinder very much resembles the Parilla Sudam of old. They make a tremendous amount of HP even on gas. I had Al Eshman build me two. Leopard bottom ends and X30 cylinders, I haven't had a chance to run them yet, but I believe it will be a potent combination once I have it sorted out. And it did not cost and arm and a leg to put together. I found broken X30 cylinders and heads from builders with customers running SKUSA type stuff. And there are some good finds as far as lepard bottom ends out there. Good luck and if you have any questions I would be more than happy to answer them.
 

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sleeve

Member
I have lying around a Bergfelt FR125 Rotax water cooled kart engine on alcohol that was converted to a jackshaft for UAS. It was a stout little guy, just gave up too much weight on the 125. There’s about a million and 1 Rotax kart engines floating around - pretty reasonable. Parts are pretty decent too, a lot of times cylinders and other engine parts get swapped out by money teams with little wear on them.
 

alvin l nunley

Premium User
Compression is the Holy Grail, what's your compression ratio? What octane fuel do you race with? I think I heard somewhere that factory stocks are limited to 93 octane. More octane won't help, in fact, it most likely will hurt! What about an EGT gauge? Running at maximum EGT is always better than less! Don't brush the idea off!
 
when we build the leopards, we machine starter mount pad off, (starter delete), rule of thumb, you can safely go 10% of total cc's (125cc = 12.5cc )., on alky, with higher compression the onboard starter will not turn engine over.. plus you don't need battery, etc.. head shape, port timing, port shape, dependent on builder.,
 

flattop1

Dawg 89
Great info guys. I don't wanna go 2) engines, and I like the idea of water cooled.... I have a younger driver who isn't good at carb adjusting on the fly......
Are you sticking the kt 100's? Two in one season is problematic .
Bigger higher tuned engine might exaggerate the problem .
 

Atomik

New member
tag engines make good opens, built a bunch of them. the leopards have the same port shape as a tt75.. Sudam piston, dual ally carbs, ported/head work.. I can build the ones I have for sale....
Hey Mike what do you have for sale? Please text to (865) 208-7478
 
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