KT100

Mini Bike & Go-Kart Parts

mustangfrank

Well-Known Member
#2
has anyone tried one of these yamaha kt100 kart engines on a minibike?

phil
Google "KT100 mini bike" there's a couple results and at least one video. I wondered about the same thing, keep getting the Horstman version of that engine in my search results reasonably cheap.

You need to DO IT...I want to hear that thing screaming!
 
#4
Google "KT100 mini bike" there's a couple results and at least one video. I wondered about the same thing, keep getting the Horstman version of that engine in my search results reasonably cheap.

You need to DO IT...I want to hear that thing screaming!
Horstman did not have a version of the Yamaha KT100, the Horstman engine package was based on the IAME Komet K71 piston port engine, Horstman called it the HPV engine package.
 

mustangfrank

Well-Known Member
#5
Horstman did not have a version of the Yamaha KT100, the Horstman engine package was based on the IAME Komet K71 piston port engine, Horstman called it the HPV engine package.
Correct, I simply was referring to the fact that they had a similar engine/package they ran on the carts. I considered getting one of either manufacturer for a mini bike build so I chimed in.
 
#6
Ok, it's on the way. I have a Bonanza BC-1000 frame for this motor. Need to do some research but it seems these motors run at 10,000 rpm so gearing is going need a little attention. I can't see a torque converter surviving at that speed.
 
#7
Correct, I simply was referring to the fact that they had a similar engine/package they ran on the carts. I considered getting one of either manufacturer for a mini bike build so I chimed in.
Ah OK, I miss understood your post, it sounded like you were saying Horstman sold a KT100 package. The Horstman HPV package runs a dry clutch, It's PTO is different than the Komet K71. Both these engine use the same bore/stroke as the KT100.
 

mustangfrank

Well-Known Member
#8
Ok, it's on the way. I have a Bonanza BC-1000 frame for this motor. Need to do some research but it seems these motors run at 10,000 rpm so gearing is going need a little attention. I can't see a torque converter surviving at that speed.
Run the clutch they ran on karts? Seems like the kart guys would have that info all sorted, at least as a good starting point.
 

desert rat

Well-Known Member
#11
On mine the starter fits into the end of the crank. Not a good pic but the starter box is at the top of the shot by the flash light. Yes I was taking the cart apart in one of my living rooms and didn't leave a mark:D
 

Attachments

#12
the motor i bought was off an ultralight, the pilot put a long rope on it so he could start it from the cockpit. it has a clutch on it with a belt gear for rpm reduction to drive the prop.
 
#13
the way this particular motor is set up is that when facing the pto the shaft spins CW. the way i want this thing to run is with the exhaust port facing forward, the carb facing the rear, and the pto rotation to be CCW when facing the pto.

i read about flipping the head, piston, and cylinder around to change rotation, but they sell CCW flywheels and other stuff.

kart guys, how does this work???
 

Neck

Growing up is optional
#14
As long as the transfer ports in the block are symmetrical, the engine doesn’t care which way the intake/exhaust ports are pointed, but that has no bearing on the engines rotation. That depends on how the flywheel/crankshaft is keyed so the spark advance is on the correct side for the desired rotation.
 
#16
They ran a KT 100 on a mini bike on the cars and cameras youtube channel. Those guys mostly run 4 strokes like predators and tillotson 225s etc. but that one ran pretty good.
 

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