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The modern day four-stroke race engine uses the lightest fastest moving piston pos- sible. Note the lack of piston skirting on this unit. Ted says its best to get a replace- ment piston with a bit more skirting than this, to increase engine live and durability. generation of Japanese four- strokes. If you are the facto- ry, its no problem to change out the Ti valves every ride. But if you’re not, then your best bet is to change them out and go with a new steel valve system. Not so much on the new KTMs, as they are doing some things differ- ent, but as far as the Japa- nese motors are concerned, you will need to change out the Ti-valves, which stretch out quickly,and will take the top end with them when they finally go out. Replace with a good high quality stainless steel valves. Dirt: What else? Teddy: Then go to a piston with a longer piston skirt for more lifespan and reliability. The stock one is exception- ally lightweight and trick, but virtually no piston skirts to speak of. There are pistons on the market (L.A. Sleeve Pro-X for example) that have longer skirts than the OEM ones and they will offer more surface area, which means a cooler running piston. Then get yourself an owners man- ual, and read it. And change the oil religiously. Dirt: How will these mods af- fect the speed on the motor? Teddy: You’re not going to change the speed of the mo- tor significantly by doing these changes. You’re going to increase the lifespan and get more riding time out of DIRT ILLustrated \\\\\\ Vol. 1 + Issue 2 + Page 30 Teddy Boyko, of Boyko Racing has over 35 years experience making dirt bike, ATV, UTV and even watercraft motors work better. He not only wants your vehicle to run better, but run longer be- tween tear downs. the engine. More ride time equals more fun. Contact Info: To send Teddy an engine tech question on your dirt bike, ATV, or UTV, send it to: teddy@dirtillustrated.com. Be sure and include your name, city and state on the bottom. For more on Teddy Boyko Racing go to: http://www.boykoracing.com or “Like” on Facebook: Or you can contact them old school style at (949)-939-5330