Quote:
Originally Posted by timcosby
item no. 1 greasing the front axle???? seems like it doesnt make sense since the bearing are what needs the grease but maybe im missing something.
item no. 2 enlarging the air box holes. seems there is more sqaure inches of opening on the airbox than the sq inches of the carb throat so i cant see where that would help if it aint restricted?
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I'm only going to speak to the airbox issue. An air box can perform several functions on an off-road motorcycle. Originally they were to prevent water and mud from being ingested into the engine, and keeping the air filter dry. I built one for my AJS scrambler in the late fifties when I switched to a dry paper element air cleaner from the stock brillo pad type air cleaner that came with the bike. The original air cleaner was only good for preventing gravel and small, low flying birds from being injested into the engine. I had read about air boxes, and seen pictures of them in English motor cycle press articles. Motor Cycle, and Motor Cycling. Anyway, first race, went bombing down and across a pitiful excuse for a creek, got a hat full of water on to that paper element air filter, and I was done for the day. So I went home and made an air box out of a kid's school lunch box, put the air filter in there, latched the box shut, and taped the door seams. Air filter to the front, air inlet to the rear, and a drain hole at the bottom rear. Worked. Eventually, air boxes came with the bike from the factory. Over time the air boxes became more and more restrictive. The one on the Hawk is pretty restrictive, as it comes. An attempt to silence the air intake noise. Unfortunatly, it also restricts the air flow to the cylinder, and the faster you go, the more it restricts it. That is why people modify their air boxes - to get more air flow per nano-second. As Pete says, that vacuum created by the piston descending in the cylinder is only available for a very short period of time, so you got to get all of the air to the carburetor possible.