430 Puma Kit

This is Donny Steele's TRX 250R with a 76 mm stroke crank shaft. It is using a 85mm LED ported Puma cylinder. The reed valve is a CR 500 V-Force reed valve. The air box is replaced with a LED sheet metal intake tract with K&N filter. The exhaust is the LED big bore pipe and silencer model TRX 465G. It is using a PVL ignition. The carburetor is a 41.5 mm Kehein PWK.

Yamaha 350 Banshee Port Modifications

An important step we do when porting Banshee cylinders is to cut boost ports into the cylinders. These ports are also called Boyesen Ports, named after Ivan Boyesen who first patented this design . The ports improve intake area and improve performance by increasing crankcase filling. Adding the boost ports increases midrange and top end hp.

As shown we machine these ports on a milling machine to insure size angle and placement.

Porting the cylinder

Because acceleration is so important We concentrate on improving efficiency and improving scavenging in the cylinder. While it is true that long duration port timing can make a lot of horsepower, that type of engine is hard to ride and has a very narrow power band. We have found that controlling the fuel charge with proper transfer port design allows us to make the big horse power, but give the advantage of a much wider power band.  Of course we improve the shapes of the exhaust and intake ports as well. Each cylinder is ported to meet the needs of the individual rider. LED porting is much more than a big tall exhaust port!

An important part of banshee porting is matching the center case transfer passages  to the transfer duct entries on the bottom of the cylinders. Stock the cases a badly mismatched to the cylinders. The photo below on the left shows the scribe marks we have laid out to grind to the correct this mismatch. As you can see a lot of material will need to be removed. The photo below on the right show the cases after being port matched to the cylinders.

 Because we often double the horse power on a 350 Banshee build the crank shaft needs attention also. We true the crank shaft so it runs true in the case. To much run out in the crank means that the shaft wobbles . This causes vibration friction and will eventually cause a failure of both e cases and the crankshaft. We then wield the crankpins to prevent the flywheels from moving on the crank pins. This helps keep the crank true and prevents twisting or spreading under hard use. 

Photos

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430 Puma Kit

Currently LED is working on a 430 Puma kit. This 430 Puma kit is for a Honda TRX 250R with an 85mm bore and 76mm stroke crank shaft. All though the Puma will make great power with out porting, on this cylinder we are doing  port work to improve transfer and exhaust port shapes. We are improving the scavenging to improve acceleration and increasing exhaust port area to increase peak horsepower. On this built we are using the oversize exhaust manifold. This engine will use on of our large volume drag pipes. The cases have also been machined to accommodate the Puma cylinder.

KTM 450XC Project

This bike is running a LED Performance KTM 530 kit.

When it first rolled into our shop it had a 530 kit with a 97mm 12.5 - 1 compression ratio, CP piston. The carburetor was bored to 43mm. It had a Motoworks slip on exhaust and a KTM 807 camshaft.

We modified stock header and built a megaphone exhaust system and muffler. We installed 31mm exhaust valves, 37mm intake valves and to accommodate the larger intake valves we installed oversized intake valve seats. We then ported the cylinder head to improve air flow and optimize velocity. To control the valve train we installed Kibblewhite valve springs and set valve seat pressures. We replaced the KTM cam shaft with a Web cam shaft and we continued to run the CP piston. We also built a sheet metal intake track with a K&N air filter attached.

The dyno chart shows the power gains of our kit by showing the power before and after.

Click on dyno charts to enlarge them.

BP MR9 fuel test, this test shows how important fuel is in the chart below. 

Here are some photos of the bike and the pipe. 

KTM Over Sized Valves

Yesterday at LED Performance we worked on a KTM 450XC 530 kit. We are installing over sized valves in this head and we are also replacing the intake valve seats.