2007-05-06 02:30:58 · 8 answers · asked by Anonymous in Cars & Transportation ➔ Motorcycles
only 1 of them got it right since my first bike was a virago. the carb boots is cracking and leaking air. if the bike goes into a very high idle when warm, and the only way to slow it down is with the choke, it's the intake boots. been there, done that. they're little rubber gaskets in front of the carbs. if they're all cracked, they're junk.
2007-05-06 03:42:21 · answer #1 · answered by Anonymous · 0⤊ 0⤋
When any engine that runs off of gasoline gets hot several factors play major roles in the performance of that engine as long as there is , Fuel, Fire,and Compression,.
One major factor about an engine that gets warmed up is that metal expands when it is hot. This is why you can take a heating torch to a solid tightened bolt and heat it up and then it will unscrew loose.
Now in an engine you have intake valves and exhaust valves on a four stroke engine.
Carbon deposits will form and these carbons get red hot when an egnine is exploding during the closed position of the vales keeping compression over 100 psi....now if the compression drops below this margin when the engine is hot several things will happen as a result of carbons, heat and expanded metal.
Common sense tells us that most likely the intake valve has carbon around the seat and setm of the valve causing the valve to get hotter than normal and when it exceeds this range of heat the metal valve will expands just slightly enough to lose compression through the seat.
Now when the valve is at the closed postion and the piston comes up and it fires the valve is not completely closed on the seat because it expanded. The will result in poor performance of your engine and it also makes a lawnmower engine not crank after you start it cold run it hot and then it won't start again.
The solution to this problem, is to take the heads off and remove the valves and clean them and grind a little bit off the stem perhaps from .001 - .002 and then it will seat again.
All valves on a push lawnmower is set at .020
Give or take you can adjust as needed based on the cylinder and ring wear, but on a motorcyle engine four stroke,,,valves will be the most common parts that go bad and make it run poor after you crank it cold and run it hot.
A cold engine what happens? Answer The valves are shrinking back to normal size that results in good compression until it gets hot.
Check the compression when the engine is cold.
Then crank it up and let it run hot and check it again.
This way you can see both suides of this story when your dealing with valves.
Have a nice day
2007-05-06 02:48:11 · answer #2 · answered by Anonymous · 1⤊ 1⤋
Try a Good Tune up and use Hot Plugs. This workes for Me with My Honda 750.
2007-05-06 02:33:46 · answer #3 · answered by thornrez1 5 · 1⤊ 1⤋
Maybe it's not because it's hot, but because the bowls are getting low. Check the filters on the petcocks in the tank. You might be getting gas starved after a few miles.
2007-05-06 11:34:19 · answer #4 · answered by Nomadd 7 · 0⤊ 0⤋
I don't know your motorcycle in particular but if it has an automatic choke it may be sticking or the mixture may just be to rich (gas>oxygen) at the carburetor. If your exhaust smoke is a little dark when it is warmed up it is likely one of these 2 problems.
2007-05-06 02:38:36 · answer #5 · answered by Noah T. Hall 3 · 1⤊ 1⤋
air leak[s] at the carb insulator plate [rubber flex mount that bolts to cyl head and carbs bolt to it . [rubber cracks]
2007-05-06 02:41:27 · answer #6 · answered by hobbabob 6 · 2⤊ 0⤋
Engine overheat.
2007-05-06 02:33:56 · answer #7 · answered by |Soldier| 3 · 0⤊ 1⤋
fuel/air mix.
2007-05-06 02:57:08 · answer #8 · answered by Anonymous · 0⤊ 2⤋