Will not idle KTM 50

SOURCE: 2005 yamaha yzf 250-unstable idle

I had the same problem, Turns out that my shims were finished, replace the chims and check clearences.

Posted on Mar 12, 2009

SOURCE: wont run...

Any water in the gas? Remove the water trap bowl at the bottom of the petcock, (gas valve). Any water or trash in the bowl? Drain a cup of gas from the tank. Any water or trash in the cup? Dump it, clean it and re-mount it, ( not all bikes have a water trap bowl ).

Get a fresh set of stock NGK spark plugs. Clean or replace the air filter. You seem to be pretty thorough in what you have done, but since plugs and filter weren't mentioned I had to ask.

Assuming you are getting air, gas and spark, and the timing is correct then it should run. Right? Not necessarily. Can the bike breathe? If pressure cant get out of the tailpipe the bike won't run. Mufflers can sometimes collapse internally. This restricts the flow of burned gasses. causing backpressure. If nothing goes out of the cylinder then nothing goes in.

Try removing the exhaust pipes. Now see if it will run. Get back to me because I would like to know what you find.

Posted on Mar 29, 2009

SOURCE: dead pw 50 and sad boy.

Many things could cause the problem. Let me see if I can help out.
You have spark, but is it enough spark? A weak battery can rob power from the coil so only a weak spark is present. Get a new stock NGK spark plug to eliminate the possibility of a problem plug.

It is good that you cleaned the carb because that would be my second target. Reset the air and idle screws. IMPORTANT > do not tighten these two screws down. Only screw these in until they LIGHTLY seat. Now turn each screw one and one half turns outward. Clean or replace the air filter and be sure the bolts are tight on the carb manifold. INSTALL AN IN-LINE FUEL FILTER. Let the float bowl fill then start the engine. Set the idle speed with the idle screw.

Remove the cylinder head. run the piston down to the bottom of the cylinder. look inside the cylinder. On th carb side (intake) you will see an intake port > a large hole that lets gas into the cylinder. Now look at the exhaust port. It is possible the exhaust port is pretty plugged up with carbon. The intake and exhaust ports should be approximately the same size. Are they? If not then remove the muffler and take a screw driver and plastic hammer and knock the carbon into the cylinder, thus enlarging the exhaust port to its' proper size and allowing the exhaust gases to escape. Vacuum the carbon out of the cylinder. De-carbon the piston top and the cylinder head.

Get back to me and tell me what you find. If more is needed we will go further.

Posted on Apr 12, 2009

SOURCE: 1981 gl1100 has 4 keihin carbs bike sat 7 years

When removing the pilot jet screw, count the number of turns to remove. Put the screw back the same number of turns then unscrew 1/4 turn.
A “very helpful” rating on this answer? Thanks!

Posted on Jul 02, 2009

SOURCE: i have a 1974 dt 250 same as an dt 360 the bike

Compression is too low!

Replace the piston rings.

Also check continuity from engine to frame till high-tension coil...
Check if breaker points aren't dirty ( clean out with fine sandpaper )
Check breakerpoint settings

Posted on Nov 01, 2009