My bro has a HONDA CR250, he has too change the spark plug every time he wants too ride, ANYBODY KNOW WHY.?
Answers:
He's fouling the plug because he doesn't know how to ride it. He's bogging the engine by keeping it at low rpm and in high gear, lugging it, which doesn't allow the unburned hydrocarbons to evacuate the cylinder, resulting in carbon build-up.
Or, his carb could be running rich, but I doubt it unless you changed your elevation from where you bought it at.
if its black then carb is jetted to rich drop the main jet down a couple of sizes
if its covered in oil then either 2 stroke mixture to high or if its 4 stroke the rings have gone.
if its wet with fuel carb problem.
The piston rings or the valve seals could be worn out,allowing excessive oil into the combustion chamber and fouling the plug..A tell tale sign is lots of blue smoke.
Unless it's a two stroke engine that is.
What condition is the plug in when he removes it?
The colour of the plug electrodes can tell you a lot about how the engine is behaving.
I don't know the bike but if it's a 2 stroke then the plug might be getting oiled up. In which case try turning the fuel switch off when it's not in use.
Is he using 2 cycle oil.if not that could be your problem. also does he have the correct plug..might be the wrong heat range.
fouled out plug, due to excess oil in cumbustion chamber. plug could be running to hot, burning it out
Something is fouling the plugs. From your information it's impossible to say what but both the kid from Mask and the guy who mentioned bad rings are on the right track. Only 2 things foul plugs; too much unburned gas or oil getting in the combustion chamber.
Piston & rings
Dirty air cleaner
Leaking R crank seal
oil mixture is too rich try changing the oil mixture.
Is he using the correct type of plug? Japanese bikes only run properly on NGKs.Make sure it's the correct plug for the bike and make sure it's an NGK.
depends on colour of plug when it's removed
black mixture too rich or choke stuck
grey to white mixture too weak
wrong grade of plug, wrong type of plug, long or short reach.
sounds like carb float not working and leaking fuel ,if it runs ok with new plug all thetime ,check float height and airfilter is clean
incorrect firing order
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