Whats a "hot start swith" and will it help my KLX?

kx80rider

Member
Mar 29, 2002
21
0
Hey, what the heck is a hot start switch? i herd alot about it, but what is it? and would it help my KLX 300? well thanks for any help
 

gooby

Member
Nov 8, 2001
497
0
this is from www.planetklx.com check it out The air in a hot cylinder of an improperly killed motor is usually very rich with fuel. Kick the motor over and open the throttle and you get even more fuel. Kick it with no throttle and you get no air and the rich condition still exists...only now your leg is tired. There is a technically simple solution available to solve this problem. A hot start button, or more appropriately, hot start valve, can be configured to inject cooler air into the cylinder, which makes starting a hot engine much easier. The process involves taking cooler air from the filtered side of the air box and delivering it through the valve, into the intake manifold between the carburetor and the cylinder. Slowly kick the bike to get to the intake stroke. Then, open the valve and kick to start the engine. The cooler air will be sucked into the cylinder and the engine will fire right up. to answer ur other question i cheated and put a bicycle comp/odo on mine
 

techman

Member
Feb 18, 2000
95
0
The simple version of a home brew hot start is to drill a hole into the intake tract between the carb and cylinder and plumb in a hose up to a valve somewhere, and have a foam filter aka like a normal air filter but smaller inline. Open the valve = let more air in to lean out the mixture for the hot condition starting. After it runs for a few seconds (4-10) close the hot start and away you go. If you do it on the cheap you can put a small valve right on the intake tract, which will always be closed when you're riding, and then will only get opened when you're stopped, the dust has settled (ie don't need a filter) and is closed again before you ride away. If you routinely slop the bike in goop or coat it in serious dust (that ultra fine almost static-like stuff) you'll want the valve's air intake filtered. The handlebar has been a convenient spot for a remote valve w/filter for some people. Other stock and mod setups are just down on the intake tract.

More pertinently, I saw a KLX that was supposedly jetted spot-on via exhaust gas analysis, ie toward the lean side, and it needed the benefit of a hot start on lots of occasions (it had a home made one). Ironically the YZ426 started better than the KLX ;) :yeehaw:

Good luck, you should add one. IMHO all 4 strokes should have one, especially bigger bores.
 
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