Athena 144 YZ Big Bore Installation PART 3.wmv

Installation of an Athena 144 Big Bore kit on a YZ 125 2 stroke

Category:

Autos & Vehicles

Tags:

• 144
• Athena
• motocross
• big
• bore
• 125
• top
• end
• rebuild
• mx
• YZ
• works
• Pro
• circuit

[dirtbikedog125848]

Hey mate! Great Vids! Ive got an 05 YZ125 with the Athena 144 kit. What jetting are you running? Currently im running a 470 main, needle on the second clip from the top and standard pilot. What does it take to push 40hp out of these motors? 45hp power even for a 144 seems a hell of alot for such a small engine!

[banfordg]

Running 430 main, 27.5 Pilot and 6BEG9-69 needle 2nd rung from the bottom in a Mikuni flat sided 38 carb with a boyesen Rad cage and a works Pro Circuit pipe. The 96-98 YZ engine was a funny wee engine, it put out 38 bhp (Brake HorsePower) at the flywheel (don't confuse this with hp (HorsePower) as this is measured at the rear wheel and is always a lower figure). Yamaha dropped the compression ratio in the later engines, polished the exhaust port and lengthened the header to protect the top end.

[banfordg]

Dropping the compression ratio and lengthening the header made the later engines more predictable and last longer, but they produced less Bhp as a consequence. For raw power then the 96-98 engine's the one to go for as yamaha 'tamed' them back a just little after that. However, this bike has already thrown me breaking three of my ribs in five different places (ouch!!). My other bikes an XR650R (the CRF450's big brother) but the 144 genuinely scares me. The power to weight ratio is plain nuts.

[rustyATV]

Why a YZ in a Husky? Were you going for a cheaper to maintain engine on a more stable handling frame?

[banfordg]

@rustyATV Yeh, pretty much. The husky's a good, rigid, predictable bike with great running gear and suspension. The original Husky engines were powerfull but the top end and cranks were fairly soft. On the other hand the YZ engine is bullet proof and easy to sqeeze power from. You're quite right, they're also much easier and cheaper to get parts for.

[buzzender]

sounds tidy. i'd be interested to know what the power delivery is like with the 144 kit, i assume its slightly softer tuned than the original 125 setup? to provide a more broad powerband? i really enjoy watching your videos and i've subcribed, hope to see more! also, could i ask, what was the benefit (if you did the transfer yourself) of putting the yamaha engine into the husky frame? thanks.

[banfordg]

@buzzender Power delivery is fairly similar to a 125 with increased bottom end torque and a vicious hit as you get on the pipe. it's like a 125.. just seriously angry. Jetting's richer on the main with the same pilot. Benefits of the hybrid? You can squeeze 40hp out of the 96-98 YZ125 engine, with the big bore 144 and some tuning it will push out over 45 hp. The Husky frame's light, rigid, and comes with Ohlin shocks, Brembo brakes, and Excel rims as standard. It's like a 45hp BMX.. scary..!

[Hood259]

Hey man very cool! I will say one thing though take off your kick lever and move it bake a few splines. That way you can save your F ing sweet pipe from it scraching it. Just food for thought, but hey check out my kx125 on my vids. And I gave you a thombs up.

[buzzender]

@banfordg nice one, i do love that hard hit of a 125 2 stroke's powerband! ah, i see, never ridden a husky, though my first mx bike was a '99 yz 125, and i loved it to pieces! have fun riding that beast, thanks!